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Wang Haige, Huang Hongchun, Ji Guodong, Chen Changchang, Lv Zehao, Chen Weifeng, Bi Wenxin, Liu Li Progress and challenges of drilling and completion technologies for deep,ultra-deep and horizontal wells of CNPC China Petroleum Exploration    2023, 28 (3): 1-11.   DOI: 10.3969/j.issn.1672-7703.2023.03.001 Abstract （2156）   HTML    PDF （1246KB）（341）    Knowledge map    Save The deep, ultra-deep and unconventional resources have grown to be the major exploration and development fields for increasing reserves and production in China. Since the 13 th Five-Year Plan period, the engineering technology has continuously been researched by focusing on the key exploration and development targets in six basins (including five oil basins and three gas basins) and drilling speed acceleration difficulties, such as high temperature and high pressure formations and narrow fluid density window, and a large number of technical achievements have been obtained. For example, the key drilling and completion technologies for deep, ultra-deep and unconventional horizontal wells have been developed rapidly, forming key technologies with the core of unconventional well structure optimization, safe, highefficiency,optimal and fast drilling, high-temperature resistant drilling fluid, finely pressure-controlling drilling and completion, and expansion pipe, and a number of landmark ultra-deep wells have successfully been drilled; The equipment has been developed such as high-power top drive, integrated geo-steering system, and green economic reservoir reconstruction tool, as well as core additives such as temperature resistance high-performance drilling fluid and high-efficiency leak-proof and plugging materials have been researched, which have accelerated the lowcost,large-scale and cost-effective development of unconventional oil and gas resources. The drilling depth of deep wells exceeds 9000 m, the horizontal section length of horizontal wells is up to 5000 m, and the maximum footage of one trip drilling is 3700 m, with some indicators comparable to those in North America. The research achievements have boosted the discovery and development of large oil and gas fields such as Tarim Fuman, Sichuan Shuangyushi and Daqing Gulong, and provided powerful engineering and technical supports for improving the utilization rate and benefits of resource exploration and development. Associated with the continuous progress of petroleum exploration and development, the engineering geological risks and new challenges faced by drilling operations occur frequently. Therefore, further research is still necessary, including accurate prediction of formation pressure, optimization and expansion of wellbore structure, well trajectory control,high-temperature resistant working fluid system, high-efficiency rock breaking and speed-up tools, as well as integration of geology and engineering, so as to realize the continuous iteration and upgrading of key drilling technologies and equipment, and support the high-efficiency exploration and development of deep, ultra-deep, and unconventional oil and gas resources. Reference | Related Articles | Metrics

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Fu Jinhua, Wang Long, Chen Xiu, Liu Jiangyan, Hui Xiao, Cheng Dangxing Progress and prospects of shale oil exploration and development in the seventh member of Yanchang Formation in Ordos Basin China Petroleum Exploration    2023, 28 (5): 1-14.   DOI: 10.3969/j.issn.1672-7703.2023.05.001 Abstract （2148）   HTML    PDF （8745KB）（40）    Knowledge map    Save As an important replacement resource, shale oil is a major exploration field widely concerned at home and abroad. The long-term exploration and development practice enabled to make significant breakthrough and progress in the exploration, development and research of shale oil in the seventh member of Yanchang Formation (Chang 7 member) in Ordos Basin: (1) On the basis of exploration breakthrough in the interlayered type shale oil and discovery of the first integral one-billion-ton level Qingcheng Oilfield, the large-scale and benefit development has been achieved, and a million-ton level national shale oil development demonstration zone has been constructed. (2) In the exploration of the laminated type shale oil, four types of laminated type have been classified of the fine-grained sedimentary complex for the first time, i.e., sandy lamina, tuffaceous lamina, high TOC argillaceous lamina, and medium-low TOC argillaceous lamina. The combination of sandy lamina and medium-low TOC argillaceous lamina is the optimal “sweet spot” interval of the laminated shale oil by evaluating their development scale, reservoir performance, oil-bearing property, movability, and crude oil properties. For the sweet spot interval, new logging evaluation methods such as M- N cross plot are used to finely interpret the complex lithology, and the directional perforation and cross-layer stereoscopic fracturing technology enable to achieve the spatial communication of sweet spots around the wellbore in horizontal section, forming technologies for the effective identification, prediction of sweet spots and reconstruction of the laminated type shale oil, and achieving a major breakthrough in risk exploration, with the primarily submitted predicted shale oil reserves of 2.05×10 8 t. (3) The laminar type shale oil is subdivided into two categories. The medium-high maturity organic shale can be developed by horizontal well, and relatively high TOC (4%-14%) and high S 1 content are key indicators for screening favorable sweet spots. While the medium-low maturity organic shale is the most favorable target for in-situ transformation research. The strategic breakthrough has been made in the exploration of continental shale oil in Chang 7 member in Ordos Basin, which is a milestone in China’s petroleum exploration and development history, but it still faces great challenges. For example, the large-scale and benefit development has been achieved of the interlayered type shale oil, but further research should be conducted on the prediction of sweet spots, production increase and efficiency improvement, and enhanced oil recovery. The laminated type shale oil is facing more challenges and greater difficulty in benefit utilization due to the completely different sedimentary settings, lithologic combination, reservoir space, and engineering quality from the interlayered type shale oil. Therefore, by focusing on the reserve quality and oil movability, hydrocarbon accumulation law should continuously be studied and the research on supporting technology should be strengthened. While for the laminar type shale oil with relative low level of exploration and understanding, the theoretical research and pilot test should steadily be promoted. Reference | Related Articles | Metrics

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Guo Xusheng, Zhang Yu, Liu Chaoying, Li Meng, Liu Shilin, Shen Baojian Theoretical and technological progress, challenges, and development directions of oil and gas exploration of Sinopec during the 14 th Five-Year Plan period China Petroleum Exploration    2025, 30 (1): 1-14.   DOI: 10.3969/j.issn.1672-7703.2025.01.001 Abstract （2116）   HTML    PDF （6399KB）（14）    Knowledge map    Save Based on a systematic review of the exploration achievements and theoretical technological progress made by China Petroleum&Chemical Corporation (Sinopec) in different fields since the 14 th Five Year Plan, the main challenges, development opportunities,and directions for oil and gas exploration have been proposed. Since the 14 th Five Year Plan, facing challenges such as relatively weak resource foundation and increasingly complex exploration targets, Sinopec has firmly adhered to its main business of oil and gas energy security, focused on expanding resources, increasing reserves, and expanding mining rights, increased efforts to expand and increase oil and gas resources, and achieved multiple strategic breakthroughs and theoretical technological innovations. Developing theoretical understanding of oil and gas accumulation in ultra deep marine fault controlled fractures and caves, and discovered Shunbei Oil Field; Tackle the theoretical and technological system of shale oil exploration in terrestrial fault basins, and promote sustained major breakthroughs in shale oil;Improve the theoretical understanding of “dual enrichment” of marine shale gas, and achieve leapfrog development in multi-layer shale gas exploration in the Sichuan Basin; Tackle the theory of tight detrital rock formation and reservoir formation, and cultivate multiple scale benefit enhanced storage sites; Tackling the mechanism of coalbed methane occurrence and enrichment, achieving strategic breakthroughs in deep coalbed methane; Significant breakthroughs have been achieved in the exploration of new marine areas such as the Beibuwan Basin. In the future, Sinopec will face three major development challenges: the reduction of mining rights, technological innovation in the exploration theory of “two deep and one non”, and the difficulty of efficient exploration. At the same time, it needs to seize four historical development opportunities: national energy security guarantee, China’s shale oil and gas revolution, green and lowcarbon transformation, and digital and intelligent upgrading. Sinopec will focus on five major projects for development, namely, leading the breakthrough in deep and ultra deep exploration in the central and western regions with the “Deep Earth Engineering”, leading the rapid transformation of mature exploration area resources with the “Shale Oil Demonstration Project”, leading the leapfrog development of unconventional natural gas with the “Shale Gas Demonstration Project”, leading the integrated benefit development with the “Tight Oil and Gas Storage Project”, and leading the new discovery of blue ocean strategy with the “Sea Area Breakthrough Project”. Sinopec will make greater contributions to ensuring national energy security and achieving the “dual carbon” goals. Reference | Related Articles | Metrics

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Wu Yugen, Men Xiangyong, Lou Yu New progress and prospect of coalbed methane exploration and development in China during the 14 th Five-Year Plan period China Petroleum Exploration    2024, 29 (1): 1-13.   DOI: 10.3969/j.issn.1672-7703.2024.01.001 Abstract （1980）   HTML    PDF （3914KB）（55）    Knowledge map    Save The development of coalbed methane (CBM) helps to achieve the goal of peak carbon and carbon neutrality as early as possible, and the industrialization of CBM development has basically been achieved in China. However, restricted by theoretical and technological factors, the development scale does not match the abundant resources. Since the 14 th Five-Year Plan period, new progress has been made in CBM exploration and development, including five aspects: (1) The large-scale development of deep CBM has begun in China, and the growth rate of CBM output has significantly accelerated; (2) Major breakthrough has been made the exploration and development of deep CBM, greatly expanding the space for industrial development; (3) Remarkable results have been achieved in reservoir stimulation and reconstruction of difficult to recover resources such as low-efficiency areas and thin coal seams in mature gas fields; (4) Compared with the 13 th Five-Year Plan period, the research focus has shifted from medium-shallow to deep CBM, great innovations have been made in CBM development theory and technology represented by large-scale horizontal well multi-stage fracturing technology in four aspects of geological understanding, drilling and completion, fracturing, and drainage and production, significantly increasing the gas production; (5) The policy environment of CBM industry has continuously been optimized. The preliminary study shows that China has abundant deep CBM resources, and deep CBM resources with a burial depth of greater than 1500 m are more than twice as those with a burial depth of small than 1500 m; The proven CBM reserves in China are dominated by middle-shallow CBM, but the recovery rate is only 7%, indicating considerable remaining resources. In addition, there are abundant CBM resources in thin coal seams in the mature gas fields, which are the realistic replacement resources. Therefore, the major breakthrough of deep CBM and the successful reservoir stimulation and reconstruction in mature gas fields have become the main driving force leading the rapid development of CBM industry, which have shown promising prospects. Based on the research results by several institutions and experts, it is expected that CBM output in China will reach 100×10 8 m 3 in 2025 and 300×10 8 m 3 in 2035. On the other hand, CBM development in China is faced with many challenges. For example, the geological theory and understanding in the new fields of deep CBM and thin coal seams need to be deeply and systematically studied, exploration and development engineering technology for deep CBM is still in the research stage, and the policy support for industrial development still needs improvement. Therefore, it is suggested to strengthen risk CBM exploration and favorable zone selection and evaluation in new fields, strengthen theoretical and technical research on high-efficiency CBM exploration and development, and strengthen policy support and development guidance for CBM industry. Reference | Related Articles | Metrics

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Hu Wenrui, Zhang Shutong, Xu Siyuan, Wang Xue Practice, challenges and prospects of oil and gas field development in China China Petroleum Exploration    2024, 29 (5): 1-11.   DOI: 10.3969/j.issn.1672-7703.2024.05.001 Abstract （1940）   HTML    PDF （640KB）（94）    Knowledge map    Save Oil and gas enterprises face greater risks and challenges in ensuring national energy security associated with the deterioration of domestic oil and gas resources, greater difficulty in increasing reserves and production, continuously higher technical requirements, and constantly increasing development costs. In this context, the development practice of oil and gas fields in China over the past century is systematically reviewed, and the trends and composition of oil and gas reserves and production since the founding of the People’s Republic of China are analyzed in detail, which enable to reclassify the stage of oil and gas field development. Based on resource types of continental, marine, low-permeability, offshore, and shale oil and gas, oil and gas field development theory and technology are deeply summarized. Furthermore, the targeted countermeasures and suggestions are proposed by focusing on the challenges faced by the development of oil and gas industry at present, such as the extremely great difficulty in the innovation of exploration and development theories, demands for further improving the adaptability of unconventional oil and gas exploration and development technologies, high cost of oil and gas development, and the more significant contradiction between resource exploration and development and land lease and environmental protection. Combined with the new development situation, the study proposes that transforming towards intelligence is the fundamental path for the development of oil and gas enterprises, unconventional oil and gas development will occupy a major position in domestic oil and gas development, and green and low-carbon transformation is the inevitable trend for the sustainable development of oil and gas enterprises. Reference | Related Articles | Metrics

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Lei Qun, Weng Dingwei, Cai Bo, He Chunming, Shi Yang, Ma Zeyuan Progress, key challenges and countermeasures of reservoir stimulation technology of PetroChina China Petroleum Exploration    2023, 28 (5): 15-27.   DOI: 10.3969/j.issn.1672-7703.2023.05.002 Abstract （1843）   HTML    PDF （1123KB）（19）    Knowledge map    Save In order to guarantee the policy of national energy resources security and accelerate domestic oil and gas production, confronting growing complex exploration objects, innovation and advance in reservoir stimulation are the most significant drivers for discovering resources and increasing reserves. By comprehensively reviewing the development history of reservoir stimulation and analyzing technical challenges for exploration target characteristics of PetroChina Company Limited (PetroChina), main progress of reservoir stimulation is systematically summarized, including the optimized design of fracture-controlled stimulation to maximize the release of reserves, the increasing operational capability of fracturing equipment, more robust downhole tools, lower cost of fracturing fluid and improved personalization, and the obvious trend of proppant to low-cost and small mesh size. The supporting role of reservoir stimulation for exploration discovery is clarified. A comprehensive analysis of the key problems faced by hydraulic fracturing is conducted in four aspects: i.e., primary elements of fracturing, fracturing design optimization, field operation quality, and technology evolution. Specifically, the countermeasures in four aspects are proposed: (1) igniting innovation of basic research to provide theoretical support for the progress of fracturing technology; (2) promoting the quality of five primary elements to support the high-quality development of reservoir stimulation technology; (3) promoting the precise technical scheme to provide guidance for more efficient exploration and development of oil and gas; (4) increasing the efficiency of technical management to create a new mode of efficient treatment of engineering management. Reference | Related Articles | Metrics

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Hou Yuting, Yang Zhaoyu, Zhang Zhongyi, Cheng Dangxing, Li Jihong, Liu Jiangyan, Zhang Yan Geological understanding and exploration potential of shale oil in the third submember of the seventh member of Yanchang Formation in Ordos Basin China Petroleum Exploration    2024, 29 (6): 17-29.   DOI: 10.3969/j.issn.1672-7703.2024.06.002 Abstract （1746）   HTML    PDF （9398KB）（9）    Knowledge map    Save There are abundant shale oil resources in the seventh member of Yanchang Formation (Chang 7 member) in Ordos Basin. The largescale interlayered type shale oil reserves have been discovered in the first-second sub-member of Chang 7 member (Chang 7 1-2 sub-member), marking a major breakthrough in the exploration and development of continental shale oil. However, there is a low level of systematic study and evaluation of new type shale oil in the third sub-member of Chang 7 member (Chang 7 3 sub-member). By using SEM, 2D NMR, full field fluorescent thin section, and infrared spectroscopy analysis, as well as identification and evaluation techniques such as geophysical exploration and logging, geological understanding and oil enrichment mechanisms are summarized. The analysis shows that: (1) The laminated shale is composed of felsic-rich lamina, organic-rich lamina, tuffaceous-rich lamina, and clay-rich lamina. The pore type is dominated by intergranular pores, dissolution pores, and intercrystal pores, with a porosity of 2%–10% and an oil saturation of 68%–88%. (2) The mud laminar type shale is composed of clayey felsic siltstone, clayey felsic mudstone, and felsic clayey shale. The pore type mainly includes dissolution pores, intercrystal pores, and bedding fractures, with a porosity of 2%–6% and an oil saturation of 65%–75%. (3) The crude oil generated by organicrich shale in Chang 7 3 sub-member was retained and accumulated, and also accumulated in felsic-rich siltstone after micro migration, showing hydrocarbon retention–micro migration and enrichment pattern. The predicted favorable zone of laminated type shale oil in Chang 7 3 submember is 5000 km 2, and that of mud laminar type shale oil is 1600 km 2, with predicted reserves of up to one hundred million tons, showing huge exploration potential. Reference | Related Articles | Metrics

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Zhao Wenzhi, Zhu Rukai, Zhang Jingya, Yang Jingru Classification, exploration and development status and development trend of continental shale oil in China China Petroleum Exploration    2023, 28 (4): 1-13.   DOI: 10.3969/j.issn.1672-7703.2023.04.001 Abstract （1575）   HTML    PDF （970KB）（27）    Knowledge map    Save By comprehensively analyzing the current classification scheme of shale oil at home and abroad, and comparing the exploration and development history, shale oil reserves and output status, and production performance of horizontal wells in China and the United States, the differences in geological conditions, resource quality, recoverability, economy and scale of shale oil between the two countries are analyzed. It is proposed to define the continental shale oil zones in China by using the nomenclature of “geographical location + shale oil” or “geographical location + stratigraphic unit + shale oil”. Furthermore, the shale oil types are classified according to two levels: Firstly, the shale oil is divided into three types based on the sandstone-to-formation ratio (the ratio of source rock to reservoir) or sedimentary facies zones, namely tight oil type shale oil, transitional type shale oil, and pure shale oil; Then the pure shale oil is further subdivided into medium-high mature shale oil and medium-low mature shale oil, or in another way, it is subdivided into light oil, thin oil, heavy oil, and viscous oil zones based on the maturity or oil properties. For the medium-high mature continental shale oil targets, efforts should be focused on the evaluation of enrichment zones/intervals in high-pressure zones, as well as trial production, and research on optimal production technology before 2025, so as to reduce costs to the maximum extent and improve initial single-well production and cumulative output. It is estimated that the annual shale oil output in China will be 600×104t to 1000×10 4t. During the 2025-2035, technology will be further upgraded and optimized to reduce costs, and the annual shale oil output is expected to be 1200×10 4t to 1500×10 4t, growing to be a major supplement to crude oil production with an annual capacity of 2×10 8t/a. As for medium-low mature shale oil, pilot test on the in-situ conversion of shale oil in Chang 7 3 sub-member in Ordos Basin is focused at present; At around 2030, the critical equipment and core technologies will be localized hopefully, and the large-scale and commercial development of shale oil will be achieved, with an annual shale oil output of ten millions of tons. Reference | Related Articles | Metrics

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Wang Qinghua, Yang Haijun, Li Yong, Cai Zhenzhong, Yang Xianzhang, Xie Huiwen, Chen Cai, Sun Chunyan Significant discovery and significance of oil and gas exploration Well Yetan1 of Kekeya peripheral in the Front Mountain of Southwest area of Tarim Basin China Petroleum Exploration    2024, 29 (4): 1-17.   DOI: 10.3969/j.issn.1672-7703.2024.04.001 Abstract （1400）   HTML    PDF （6314KB）（16）    Knowledge map    Save The Yetan1 well in Kedong tectonic belt, west Kunlun thrust belt in the front mountain of southwest area of Tarim Basin, has made a major breakthrough in the Permian Pusige Formation, marking the discovery of an important exploration successor system in southwest area of Tarim Basin. Based on the regional geological data and the field outcrop, drilling and seismic research, the reservoir-forming conditions of the Permian Pusige Formation sandstone around Kekeya are reunderstood. A new round of research holds that the upper member of Permian Pusige Formation has a semi-deep lacustrine facies source rock with an area of 1.0×10 4km 2 and a maximum thickness of 800m. The organic matter abundance is 0.89%~1.5%. The source of organic matter is mainly bacteria and algae, and the type of organic matter is mainly type II. Hydrocarbon generation potential S 1+ S 2 is 1.47-2.78mg/g. Due to the tectonic uplift of the Kunlun Mountains, the lower member of the Permian Pusige Formation in the periphery of Kekeya subdivision entered the continental sedimentary system, and the delta front and shoal shallow lake sand bar high-quality sandstone reservoirs developed in the lower submember II, withsand body thickness of 42.5-63m and sand-land ratio of 27%-47%, which are a set of widely distributed reservoirs. It is a high quality reservoir-cap association with lower submember I of Pusige Formation and upper mudstone member of Pusige Formation. According to the structural pattern analysis after drilling of Yetan 1 well, it is concluded that the Kekeya subperipheral developed two phases of Indosinian and Alpine tectonic deformation, Palaeozoic imbricated thrust, strong overthrust, trap rows and belts, and the further extrusion and uplift in the Alpine period were partially complicated, and the imbricated thrust belt formed is a favorable exploration area. According to the analysis of natural gas dryness coefficient of the Pusige Formation, the R o is 1.31%-1.42%, which is similar to the maturity phase of the source rock, indicating that the oil and gas come from the foote overlying source rock and have undergone the accumulation process of early oil and late gas, and the accumulation has the characteristics of "hydrocarbon supply by the overlying foote, new layers produce and ancient layers storage, lower layers produce and upper layers storage, transport by fault ". Through re-comprehensive analysis, it is believed that the Permian Pusige Formation traps in this area are distributed in rows, and 9 traps are found, covering an area of 307.7km 2, with 286 billion square meters of natural gas resources and 143 million tons of condensate oil. Meanwhile, several favorable exploration targets such as PT1 well, PS1 well and PS2 well are selected and have great exploration prospects. It is expected to become an important replacement field for large-scale natural gas storage and production. Reference | Related Articles | Metrics

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He Xipeng, Zhang Peixian, Gao Yuqiao, Wang Kaiming, He Guisong, Ren Jianhua, Gao Quanfang, Zang Suhua Challenges and countermeasures for beneficial development of unconventional oil and gas resources in China China Petroleum Exploration    2025, 30 (1): 26-41.   DOI: 10.3969/j.issn.1672-7703.2025.01.003 Abstract （1284）   HTML    PDF （565KB）（29）    Knowledge map    Save Based on in-depth investigation on the differences in exploration and development, key technologies and operation modes of unconventional oil and gas at home and abroad, and integrated with the current situation of unconventional oil and gas exploration and development in China, some challenges in unconventional oil and gas industry are put forward, including strategic resource replacement,key development technologies, management system and mechanism, as well as digital intelligence and green construction. By referring to experience and enlightenment of “shale revolution” in North America, and focusing on key factors such as resource, technology, management,cost and benefit, five countermeasures and suggestions are proposed to promote the beneficial development of unconventional oil and gas in China: (1) Strategic planning in all domains. Strengthening the top-level design of development strategy, optimizing domestic resource base,and expanding overseas resource market to further consolidate the resource base for the large-scale development of unconventional oil and gas. (2) Full life cycle evaluation. Conducting long-term trial production test of single well to identify the production law, strengthening the evaluation of key pilot wells, conducting modeling and numerical simulation integrated study, and implementing development technological policies, so as to improve single-well production performance and enhance oil and gas field recovery factor. (3) Full-chain technology iteration. With the aim of addressing problems and achieving goals, researching on key core technologies for beneficial development,efficiently promoting the construction of unconventional oil and gas demonstration zones, and integrating feasible and replicable practices to comprehensively promote the beneficial development of unconventional oil and gas resources. (4) Overall planning of resources. Promoting the operation mode of “four integrations, diversified cooperation and market-orientation” to achieve production and efficiency improvement and mutual benefits, and enhance the vitality of unconventional oil and gas development. (5) Whole-process green and intelligent operation.Constructing a large scientific research system, a large operation system and a large environmental protection system to create a new development pattern of the unconventional oil and gas industry. The five countermeasures aim to promote the large- scale and beneficial development of unconventional oil and gas resources in China, ensure the sustainable and high-quality development of domestic oil and gas industry, and fulfill the major responsibility and mission of securing the energy rice bowl. Reference | Related Articles | Metrics

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Yang Yang, Zheng Xingfan, Xiao Yuxiang, Lei Zhengdong, Xing Housong, Xiong Tie, Liu Mingyang, Liu Shujian, Hou Mingqiu, Zhang Yali Progress in exploration and development of high-mature shale oil of PetroChina China Petroleum Exploration    2023, 28 (3): 23-33.   DOI: 10.3969/j.issn.1672-7703.2023.03.003 Abstract （1269）   HTML    PDF （909KB）（28）    Knowledge map    Save Shale oil is an important strategic resource to ensure the long-term steady oil production and production growth in China.PetroChina has made significant exploration breakthroughs in Ordos, Junggar, and Songliao basins, and has discovered shale oil with various lithofacies association types. In order to ensure the steady oil production of 2×10 8 ton/a and improve the security of national energy supply,PetroChina strengthened its efforts in shale oil exploration and development in 2021 and achieved progress in four aspects: (1) The large-scale shale oil development has been conducted in Longdong area, and an integral shale oil demonstration zone has been established with a capacity of one million tons; (2) The construction of Xinjiang Jimsar and Daqing Gulong National Continental Shale Oil Demonstration Zones has been promoted, obtaining shale oil production capacity of up to one million tons in Jimsar area and opening a new chapter in pure type shale oil development in Gulong area; (3) Great efforts have continuously been made in new areas, and historic exploration breakthroughs have been achieved in several basins; (4) The theory, technology, and management have continuously been innovated, obtaining significant results in quality and efficiency improvement. On the whole, the exploration and development different types of shale oil are still in different stages, but there is still a gap to achieve the large-scale benefit development. Reference | Related Articles | Metrics

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Zhang Yu, Zhao Peirong, Gao Shanlin, Zhang Hua, Shen Baojian, Qian Keran, Wang Pengwei, Li Peng Practice and enlightenment of high-quality shale oil and gas exploration of Sinopec China Petroleum Exploration    2025, 30 (1): 15-25.   DOI: 10.3969/j.issn.1672-7703.2025.01.002 Abstract （1234）   HTML    PDF （678KB）（12）    Knowledge map    Save Progress and achievements of shale oil and gas exploration of Sinopec are systematically reviewed, and major measures for highquality exploration are summarized. In addition, the future research directions of shale oil and gas are proposed. In recent years, Sinopec has implemented a series of measures for the high-quality shale oil and gas exploration, covering the full chain of planning, theoretical technology,engineering and management, which are characterized by “planning guidance promoted by top-level design, technological innovation promoted by basic research, economic benefits promoted by technological iteration, and large-scale reserve increase promoted by collaborative work”. As a result, a number of leading demonstration projects have been constructed, including marine shale gas in new strata and new areas in Sichuan Basin and multi-type continental shale oil in the eastern fault basins, which vigorously promotes the high-quality and collaborative development of shale oil and gas exploration in multiple fields. In the future, Sinopec will solidify the foundation of shale oil and gas resources,strengthen confidence in shale oil and gas exploration, continue to deepen and improve the “dual enrichment” theory, pursue the concept of value leading the overall situation, adhere to the six “integrated” operation modes, promote shale oil and gas strategic breakthroughs and discoveries with high quality, and identify positions for increasing reserves and production on a large scale, so as to make greater contributions to ensuring national energy security. Reference | Related Articles | Metrics

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Lin Yongmao, Lei Wei, Miao Weijie Practice of geology and engineering integration in deep tight gas development: a case study of Xujiahe Formation in western Sichuan Basin China Petroleum Exploration    2024, 29 (3): 21-30.   DOI: 10.3969/j.issn.1672-7703.2024.03.003 Abstract （1218）   HTML    PDF （11794KB）（5）    Knowledge map    Save There are abundant natural gas resources in Xujiahe Formation in Xinchang-Hexingchang in western Sichuan Basin, with proven reserves of 1700×10 8 m 3 in Sinopec exploration blocks. The reservoir is characterized by “one-deep, two-high, and two-low”, including great burial depth of gas reservoir (4500-5500 m), high formation pressure (pressure coefficient of 1.4-1.7), high fracture pressure (110-165 MPa), ultra-low porosity (average of 3.7%), and ultra-low permeability (average of 0.07 mD), which brings multiple challenges to geological theoretical understanding and high-efficiency gas development, and restricts the progress of exploration and development. Based on the research idea of geology and engineering integrated practice, understanding of tight sandstone gas migration and accumulation has been deepened, and gas accumulation mechanism and enrichment and high-yield production laws have been identified. By starting from the detailed analysis of development mode of geological sweet spots, the formation mechanism of gas reservoir sweet spots has been determined, and a sweet spot geological model has been established. By applying fracture and reservoir fine seismic characterization and quantitative prediction technology, and optimizing drilling and reservoir reconstruction technologies, the geology and engineering integrated collaborative research on key technologies such as geology, geophysics, drilling and completion has been conducted, and the practice of technology and economy integration has been implemented. The successful application of technical sequences supports the large-scale production of the gas field, with a cumulative production capacity of over 10×10 8 m 3, and new addition proven geological reserves of 1300×10 8 m 3 in Hexingchang Gas Field, which further confirms that the integration of geology and engineering is a necessary way for the effective development of low-grade gas reservoirs, promotes the beneficial development of Xujiahe gas reservoir in western Sichuan Basin, and provides reference for the exploration and development of tight and difficult to use reserves, especially deep tight gas. Reference | Related Articles | Metrics

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Li Guoxin, He Xinxing, Zhao Qun, Zhang Junfeng, Zhang Guosheng, Zhang Lei, Xu Wanglin, Zhang Bin, Yang Zhi Theory, technology, exploration and development progress and prospects of coal-rock gas in China China Petroleum Exploration    2025, 30 (4): 1-17.   DOI: 10.3969/j.issn.1672-7703.2025.04.001 Abstract （1096）   HTML    PDF （7026KB）（7）    Knowledge map    Save Coal-rock gas is a new type of unconventional natural gas resource. In recent years, strategic breakthrough has been achieved, which has great significance for ensuring energy security in China. The research progress in geological theories, key technologies, and current status of exploration and development of coal-rock gas are systematically discussed, and the development prospects are put forward based on resource potential analysis results. The study results show that: (1) A consensus has basically been reached in the industry on the connotation of coal-rock gas. The coal rock shows a typical dual-pore media reservoir. Coal-rock gas is composed of complex gas components and high content of free gas, which has characteristics of migration and accumulation, and good preservation conditions are required for the formation of effective gas reservoir. (2) The understanding of coal-rock gas accumulation mechanism and the theoretical framework of whole petroleum system of coal measures have primarily been established, forming a “three-field controlling” coal-rock gas accumulation mechanism, and two types of gas accumulation and enrichment models, i.e., “integration of source rock and reservoir, and box-type sealing” and “multi-source supply, and gas enrichment in reservoir at high structural parts”. (3) A series of technologies have initially been developed, such as coa-rock gas resource assessment, geological and engineering sweet spot evaluation, laboratory testing, horizontal well multi-stage fracturing, production capacity evaluation, and production optimization. In addition, technologies such as water-reducing/water-free reservoir reconstruction and stereoscopic development of multi-layer and multi-source gas in coal measures are actively being researched. These technologies have supported the cumulative proven coa-rock gas geological reserves of 5968×10 8 m 3 , and the output reaching 27×10 8 m 3 in 2024. (4) It is preliminarily estimated that the coal-rock gas geological resources exceed 38×10 12 m 3, possessing the resource foundation for achieving an annual output of 300×10 8 m 3 by 2035, which shows a new growth point in the natural gas industry. (5) Three major challenges in coal-rock gas exploration and development are pointed out, and six key theoretical and technological research directions are proposed to promote the high-quality development of coal-rock gas industry in the future. Reference | Related Articles | Metrics

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Zhang Yu, Zhao Peirong, Liu Shilin, Liu Chaoying, Cheng Zhe, Chen Qian, Chen Gang, Zhang Feiyan Main exploration progress and development strategy of Sinopec during the 14 th Five-Year Plan period China Petroleum Exploration    2024, 29 (1): 14-31.   DOI: 10.3969/j.issn.1672-7703.2024.01.002 Abstract （1093）   HTML    PDF （18858KB）（15）    Knowledge map    Save A systematic review is conducted on the high-quality exploration activities, theoretical and technological progress, and exploration achievements of Sinopec during the 14 th Five-Year Plan period, and a development strategy is proposed for the future petroleum exploration. Since the 14 th Five-Year Plan period, Sinopec has strengthened its confidence in resource development and vigorously promoted high-quality exploration practices, which support to make significant exploration achievements in fields such as deep carbonate rocks, continental shale oil, deep shale gas, clastic rocks in western regions, subtle oil and gas reservoirs in mature exploration areas, and deep CBM in Tarim, Sichuan, Bohai Bay, Junggar, and Ordos basins, solidifying reserve basis for stable oil output growth and rapid gas output growth. In addition, significant progress has been made in the development and improvement of deep strike-slip fault-controlled fracture-cavity type hydrocarbon accumulation theory, the innovative shale oil reservoir formation, hydrocarbon accumulation and enrichment theory, and the deep understanding of “dual enrichment” of marine shale gas and differential enrichment mechanisms of oil and gas reservoirs in tight clastic rocks. Furthermore, the key exploration and engineering technologies for targets with complex geological and reservoir structural conditions, represented by seismic exploration, well drilling and completion in deep to ultra-deep formations, wireline logging, mud logging and well testing in ultra-deep formation, and horizontal well fracturing, have been researched and developed. Looking ahead, Sinopec has a solid resource foundation in its exploration areas for achieving steady oil output and rapid increase in gas production. The exploration work will focus on three core responsibilities of securing and expanding mining rights areas, achieving exploration breakthroughs, and increasing reserves and resources on a large scale. Guided by deep earth engineering, shale oil and gas demonstration projects, benefit development of tight clastic rock oil and gas reservoirs, and coordination of conventional and unconventional resources, efforts will be strengthened to accelerate the strategic breakthroughs, and establish large-scale reserve increase bases, so as to further consolidate resource foundation for the sustainable development of the upstream. Reference | Related Articles | Metrics

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Mao Xinjun, Li Yanping, Liang Zeliang, Zhu Ming, Yao Weijiang, Li Shubo, Pan Tuo, Hu Zhengzhou, Wang Yang Hydrocarbon accumulation conditions and exploration potential of the Jurassic coal measure gas in Junggar Basin China Petroleum Exploration    2024, 29 (4): 32-44.   DOI: 10.3969/j.issn.1672-7703.2024.04.003 Abstract （1078）   HTML    PDF （7608KB）（12）    Knowledge map    Save Two sets of coal seams are widely distributed in the Jurassic Xishanyao and Badaowan formations in Junggar Basin, and there are abundant coal measure gas resources. However, as a completely new field of natural gas, the level of basic research is low, and gas accumulation characteristics, enrichment laws and resource scale in the basin are unclear. In 2020, a risk exploration well CT1H was drilled to explore gas bearing property of deep coal rocks, and a maximum daily gas rate of 5.7×10 4 m 3/d was tested, as well as a steady gas rate of 2×10 4 m 3/d in trial production, confirming the high and steady production capacity of coal measure gas. A systematic study on coal rock petrological characteristics, reservoir performance, evolution characteristics and control factors for gas accumulation in coal measure strata has been conducted, which indicates that the thermal evolution degree of coal rocks is low, with a medium-low coal rank, and the coal reservoir in Xishanyao Formation is dominated by meso-macro pores, while that in Badaowan Formation is mainly micro-small pores; By combining with multiple factors controlling gas accumulation in coal measure strata, such as source rock, structure, coal reservoir, and abnormal gas logging shows, the potential fields of coal measure gas in the basin have been classified and evaluated. Two favorable exploration areas including Dinan-Baijiahai and Qigu areas have optimally been selected, and coal measure gas resources are more than 1×10 12 m 3 with a burial depth of 2000-4000 m. Reference | Related Articles | Metrics

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Bai Xuefeng, Yang Yu, Li Junhui, Wang Youzhi Accumulation conditions and exploration prospects of tight gas reservoirs in the fifth member of the Upper Triassic Xujiahe Formation in Yilong–Pingchang area,Sichuan Basin China Petroleum Exploration    2025, 30 (1): 42-55.   DOI: 10.3969/j.issn.1672-7703.2025.01.004 Abstract （1062）   HTML    PDF （4358KB）（10）    Knowledge map    Save An exploration breakthrough has been made in the overpressure tight sandstone gas reservoir in the fifth member of the Upper Triassic Xujiahe Formation (Xu 5 member) in Well LG 163, drilled in Yilong–Pingchang area, Sichuan Basin, marking an important field for increasing reserves of continental facies tight oil and gas with a large scale and benefits. Based on the discovery of tight sandstone gas in Well LG 163 and the previous exploration results in Xujiahe Formation, and combined with the experimental and lab test data, a systematic study of reservoir characteristics and gas accumulation and evolution in Xujiahe Formation in Yilong–Pingchang area has been conducted focusing on the hydrocarbon generation center in Xu 5 member. The study results suggest that thick dark shale was developed in Xu 5 member in Yilong–Pingchang area, with an average TOC of greater than 1%, Type Ⅱ 2-Ⅲ organic matter, and high–over maturity, showing a good source rock as a whole. The meandering river delta front facies sandstone reservoir was developed in the southeastern part, with consistent distribution in lateral, porosity range of 1.5%–7.7% and an average of 4.83%, well-developed microfractures, and good reservoir physical properties. The tight sandstone reservoir in the second sub-member (Xu 5 2 sub-member) was wrapped in source rock in Xu 5 member, forming a high-quality hydrocarbon accumulation combination of “sand wrapped by source rock” in vertical. The formation overpressure is generally observed in Xu 5 member, and the pressure coefficient gradually increases from the slope to the center of the lake basin, resulting in tight gas charging and preservation under overpressure conditions. The comprehensive study of source rock conditions and reservoir physical properties indicates that the high-quality source rock in Xu 5 member has an area of 5600 km 2, the sand enriched zone has an area of 3553 km 2, and the predicted tight gas resources are 5600×10 8 m 3, showing good exploration prospects, which is expected to be a major replacement field for obtaining largescale gas discoveries. Reference | Related Articles | Metrics

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Shi Yujiang, He Yufei, Wan Jinbin, Guo Xiaokai, Yu Hongguo, Yang Renjie Research on logging evaluation methods for geological quality and gas content of deep coal measure gas China Petroleum Exploration    2024, 29 (4): 128-145.   DOI: 10.3969/j.issn.1672-7703.2024.04.010 Abstract （1038）   HTML    PDF （4993KB）（13）    Knowledge map    Save The deep coal measure gas is one of the key exploration and production targets in the field of unconventional oil and gas exploration,which has gradually grown to be a major source of natural gas resources in China. Compared with medium-shallow coalbed methane (CBM)reservoirs, the deep coal measure gas reservoirs are characterized by more complex gas occurrence and geological characteristics. For example,in B block in Ordos Basin, the deep coal measure gas shows higher gas content, better coal structure, poorer reservoir physical properties, and higher reservoir temperature, pressure, and formation water salinity than that in middle-shallow formations. The geological characteristics of deep CBM have systematically been analyzed, which support to summarize the typical logging response characteristics of coal seams, such as low density, low GR, high neutron, high acoustic time difference, and high resistivity, and achieve the identification of coal reservoir; After analyzing the different logging response characteristics of various coal structures, some logging parameters have optimally been selected to establish coal structure factors applicable for the target area and classify coal structure types; Based on experimental results and combined with logging response characteristics of target interval, a porosity logging interpretation model has been established by using variable matrix parameters of coal rocks; Based on the experimental data, the correlation between logging response and macerals has been analyzed, as well as that between macerals, which supports to construct a proximate component logging evaluation model in the target area; After conducting geological quality parameters evaluation such as coal seam identification, maceral calculation, and coal structure classification, the conventional and NMR-isothermal adsorption combined gas content evaluation technology has been developed to calculate both free gas and adsorbed gas in deep coal reservoirs, providing guarantees for the calculation of deep coal measure gas resources and reserves; Furthermore, with the aim of further improving the exploration efficiency and development benefits of deep coal measure gas, logging suggestions and technical research directions for the evaluation of deep coal reservoir have been proposed, so as to meet the goal of high-quality development of the deep coal measure gas industry. Reference | Related Articles | Metrics

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Shi Yujiang, Cai Wenyuan, Liu Guoqiang, Yuan Chao, Zhang Wei, Di Shuhua, Li Si, Wang Shaoqing Full diameter core 2D NMR characteristics of pore fluid in shale oil reservoir and evaluation method China Petroleum Exploration    2023, 28 (3): 132-144.   DOI: 10.3969/j.issn.1672-7703.2023.03.011 Abstract （988）   HTML    PDF （7404KB）（38）    Knowledge map    Save How to objectively evaluate the pore fluid in shale oil reservoir and accurately measure and quantitatively characterize parameters such as oil saturation and mobile oil content in shale oil and tight oil reservoirs are key technical problems that need to be solved urgently.The vehicle-mounted mobile full diameter core NMR measurement instrument is firstly introduced in domestic to conduct on-site core testing analysis and shale oil evaluation, which supports to realize the continuous, high-precision, non-destructive and rapid NMR scanning of drilled core on well site, make up for the shortcomings of NMR logging and indoor core experiments, and fill the blank of on-site measurement technology of full diameter shale oil core in China. Based on field core description, other supporting experimental data and well testing verification, the characteristics of 2D NMR T 1- T 2 spectrum of various fluid components are systematically summarized, the change rule of T 1/ T 2 ratio of oil and water fluid signals in pores with different diameters is identified, and the pore fluid component analysis method and identification standard are established by using 2D NMR spectrum characteristics of full diameter core, which support to realize the accurate identification of pore fluid components and quantitative interpretation of fluid saturation of shale oil, tight oil and complex clastic rock reservoirs. The technology of vehicle-mounted mobile full diameter core NMR measurement has played an important role in the exploration and evaluation of Gulong shale oil in Songliao Basin, Chang 7 3 shale oil in Ordos Basin, as well as in Hetao Basin, and has widely been applied in tight oil and gas oilfields in Daqing, Changqing, Xinan, Huabei, and Xinjiang oilfields, in which good results have been achieved. Reference | Related Articles | Metrics

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Wang Qinghua, Yang Haijun, Cai Zhenzhong, Yang Xianzhang, Zhang Liang, Jiang Jun, Zhou Lu Major breakthrough and significance of petroleum exploration in Well Tuotan 1 on the south slope of Kuqa Depression, Tarim Basin China Petroleum Exploration    2023, 28 (5): 28-42.   DOI: 10.3969/j.issn.1672-7703.2023.05.003 Abstract （971）   HTML    PDF （23060KB）（9）    Knowledge map    Save A major breakthrough has been made in the Cambrian buried hill dolomite reservoir in Well Tuotan 1 in Wensu-Xiqiu area on the south slope of Kuqa Depression in Tarim Basin, which is of great significance to the exploration of multi-target buried hill on the hydrocarbon facing side on the south slope of Kuqa Depression. Due to the complex geological conditions, there is a lack of clear understanding on hydrocarbon enrichment law, and it is difficult to identify geological structures and characterize traps, which restrict the petroleum exploration in the buried hills in the study area. Based on the systematic analysis of structural features, stratigraphic distribution in buried hill, source rock-reservoir-cap rock assemblage, hydrocarbon transport system, and exploration practice, a new pattern of hydrocarbon accumulation in the buried hill has been established. The Paleozoic structure in Wensu-Xiqiu area is a back thrust structure controlled by the front thrust Shajingzi-Xiqiu Fault and recoil thrust Wushinan Fault, which is further complicated by two secondary back thrust faults F1 and F2, forming three rows of Paleozoic buried hill structures, with the stratigraphic age from old to new from the near fault to the far fault area in each row of structures. Among them, the Cambrian buried hill strata have the largest distribution range in a NEE direction. The buried hill reservoirs are mainly composed of dolomite of restricted platform granular beach facies, and the high-quality fractured-vuggy type dolomite reservoirs are contiguously distributed after reconstructed by multi stage tectonic activities and long-term exposure and erosion. The hydrocarbon accumulation assemblage of the buried hill oil and gas reservoirs is composed of dual hydrocarbon supply by mudstone source rocks in the Triassic Huangshanjie Formation and the Jurassic Chakmak Formation, fractured-vuggy type dolomite reservoir, and cap rock of the overlying Paleogene gypsum salt rock; The hydrocarbon accumulation is characterized by “distant hydrocarbon supply from Kuqa Depression, hydrocarbon transport by unconformity surface, and hydrocarbon enrichment in structures on the hydrocarbon facing side”, with the main hydrocarbon accumulation period in the late Himalayan (4-1Ma). The successful drilling of Well Tuotan 1 has confirmed the huge exploration potential of multi-row and multi-type buried hills in Wensu-Xiqiu area, with the re delineated buried hill trap area of 840km 2, and the discovered oil resources of about 2.0×10 8t and natural gas resources of about 590×10 8m 3, which is expected to be a new strategic replacement area for increasing oil and gas reserves and production. Reference | Related Articles | Metrics

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Zhou Lihong, Chen Changwei, Yang Fei, Cui Yu, Song Shunyao, Guan Quansheng, Zhou Fengchun Research and breakthrough of benefit shale oil development in Cangdong Sag, Bohai Bay Basin China Petroleum Exploration    2023, 28 (4): 24-33.   DOI: 10.3969/j.issn.1672-7703.2023.04.003 Abstract （963）   HTML    PDF （1841KB）（18）    Knowledge map    Save The large-scale and benefit development of shale oil in the second member of Kongdian Formation (Kong 2 member) in Cangdong Sag in Huanghua Depression face multiple challenges, such as evaluation and optimal selection of main production layers of medium-low mature shale oil, stereoscopic development and production of multiple vertical sweet spots, optimal and fast drilling and completion of horizontal section with a length of 2000 m in complex fault blocks, high-efficiency volumetric fracturing of laminated shale reservoir and high-efficiency lifting of shale oil with high viscosity and high wax content. Go through four stages of shale oil exploration, i.e., research, breakthrough in horizontal wells and pilot test of production capacity evaluation, 60% of the horizontal wells in production have a single well EUR of less than 2.0×10 4t, and the low single well oil rate has become a bottleneck problem restricting the benefit development of lacustrine shale oil. By comprehensively analyzing wireline logging, mud logging, fracturing parameters and production data of Kong 2 member shale oil in 47 production wells, the systematic research has been conducted on sweet spot evaluation and optimal selection of sealing box, well pattern deployment, geosteering while drilling, fracturing reconstruction, and production regime for the lacustrine shale oil in complex fault blocks, and three sweet spot layers (C1, C3 and C5) have been identified for benefit shale oil development in Guandong area, with an favorable area of 42-53.3 km 2 and the estimated Class Ⅰ resources of 1.54×10 8t. The pilot test of benefit shale oil development has been conducted on two 10 m-level sweet spot layers (C1③ and C3⑧) in Kong 2 member on No.5 platform in Cangdong Sag, in which the drilling difficulty of long horizontal section by water-based drilling fluids in complex fault blocks has been solved, the high-efficiency fracturing technology for laminated shale oil has been innovated, and permeability improvement, swelling energization and viscosity reduction of miscible fluids have been achieved of the laminated shale reservoir, with the tested single well peak oil output of 39.6-122.3t. As of June 22, 2023, the five pilot wells had been put into production for 174-201 days, and the cumulative oil output was 3.34×10 4t. The predicted cumulative oil output in the first year is 6.5×10 4t, and the average EUR of a single well is 4.11×10 4t, which indicate that the large-scale and benefit development mode of lacustrine shale oil has been established in complex fault blocks. Reference | Related Articles | Metrics

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Liu Xiaobing, Dou Lirong Practice and enlightenment of deepwater petroleum exploration of international major oil companies: a case study of Guyana Stabroek block China Petroleum Exploration    2023, 28 (3): 78-89.   DOI: 10.3969/j.issn.1672-7703.2023.03.007 Abstract （961）   HTML    PDF （4964KB）（179）    Knowledge map    Save In recent years, exploration breakthroughs have continuously been obtained in deepwater fields by major international oil companies. Among them, the joint venture company led by ExxonMobil has discovered 31 deepwater oil and gas fields in Stabroek block in Guyana, making it a rising star in the petroleum industry in South America and driving the exploration boom in the peripheral offshore areas. Guyana Basin spans Guyana and Suriname offshore areas. ExxonMobil’s petroleum exploration in Guyana Basin mainly experienced three stages, namely, the advanced layout in Suriname offshore area during the 1957-1982, re-exploration in Guyana Basin and long-term research in Guyana offshore area during the 1999-2015, and a series of discoveries by applying new geological understanding and seismic technologies since 2015. The exploration practice of major international oil companies in Guyana, especially the joint venture company led by ExxonMobil, shows that it is a feasible and typical way to implement risk exploration by conducting comprehensive regional geological study and applying new data to strengthen exploration confidence and introducing partners to share risks and benefits, which provides reference for Chinese oil companies in promoting overseas petroleum exploration business from “going global” to “going better”. Reference | Related Articles | Metrics

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Liu Guoyong, Song Yong, Mao Xinjun, Tang Yong, Guo Xuguang, Wei Yanzhao, Gong Deyu Main strategies and orientations for high-efficiency exploration in Junggar Basin China Petroleum Exploration    2024, 29 (1): 47-64.   DOI: 10.3969/j.issn.1672-7703.2024.01.004 Abstract （961）   HTML    PDF （9200KB）（13）    Knowledge map    Save The petroleum exploration in Junggar Basin has entered a new stage of exploration in hydrocarbon rich sags, which faces new challenges such as increasing burial depth, more scattered and subtle exploration targets, poorer reservoir porosity and permeability, and low upgrade rate and recovery rate of reserves. It is an urgent task to improve exploration effectiveness and achieve benefit development of oil fields. The new round of integrated research and re-understanding of the basin indicates that the spatial distribution of multiple source kitchens in Junggar Basin are complementary, showing “abundant oil and rich gas”, which has broken through the traditional understanding of “abundant oil but less gas” in the basin; There are four types of large-scale effective reservoirs in hydrocarbon rich sags, with orderly distribution in lateral and superposition in vertical direction; Three types of hydrocarbon accumulation systems are identified, such as orderly accumulation of conventional and unconventional oil and gas in source rock, large-scale hydrocarbon accumulation in regressive fan delta facies glutenites above source rock, and stereoscopic hydrocarbon accumulation in medium-shallow fault-sand coupling reservoirs. In combination with the resource characteristics, new geological knowledge, adaptability of exploration and development technologies, and goal of sustainable and benefit development in Junggar Basin, strategies for high-efficiency exploration are proposed, including “simultaneous exploration of oil and gas, emphasis on both conventional and unconventional oil and gas, co-exploration of deep and shallow oil and gas, and reserve increase in multiple fields”, and three major exploration orientations and nine major exploration fields are put forward, so as to support the benefit and sustainable development of the oilfield. Reference | Related Articles | Metrics

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Wang Qinhua, Yang Haijun, Cai Zhenzhong, Li Yong, Yang Xianzhang, Chen Cai, Chen Changchao Exploration breakthrough and significance of Ordovician fault controlled karst hydrocarbon reservoirs of Well Luotan1 in Maigaiti Slope of Tarim Basin China Petroleum Exploration    2024, 29 (2): 1-15.   DOI: 10.3969/j.issn.1672-7703.2024.02.001 Abstract （959）   HTML    PDF （9238KB）（33）    Knowledge map    Save The Luotan1 well in the Maigaiti slope of Tarim Basin has made a new breakthrough in the Ordovician carbonate rocks, marking the first exploration breakthrough of a new type of Ordovician fault controlled karst carbonate reservoirs in the Maigaiti slope and marking the discovery of an important strategic replacement area in the slope area. Based on regional drilling, logging, seismic and other data, a comprehensive analysis of the laboratory data of well Luotan1 is carried out to further understand the reservoir formation conditions of Ordovician carbonate rocks in the Maigaiti slope. The formation of Ordovician carbonate fault controlled karst reservoirs in the Maigaiti slope is mainly related to strike slip fault activity, and is one of the three main reservoir formation models in the Maigaiti slope. At present, it has been discovered that hydrocarbon in the Maigaiti slope comes from the source rocks of the Cambrian Yuertus Formation, and the basement paleostructure controls the sedimentation and distribution of the Lower Cambrian source rocks. The slope area has three stages of hydrocarbon charging and accumulation: the Caledonian, Hercynian-Indosinian, and Himalayan periods. Hydrocarbon source rocks, paleotectonic evolution, and the faults connecting hydrocarbon source rocks control the multi-stage hydrocarbon accumulation. The fault active stages and fault penetrating layers determine the hydrocarbon enrichment layers and reservoir properties. The Maigaiti slope is characterized by well-developed Ordovician strike slip faults, with an extension distance of over 1000km, which control the distribution of fault controlled karst carbonate reservoirs and hydrocarbon reservoirs. It has clear zoning characteristics on the plane, with a large resource scale and strong deployability, demonstrating huge exploration potential. It is an important practical field for large-scale hydrocarbon exploration discovery and strategic succession in the southwestern Tarim Basin. Related Articles | Metrics

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Xie Guiqi, Lin Hai, Liu Shiduo, Liu Yong, Wan Youyu, Zhang Chengjuan, Li Yafeng, Cui Ronglong, Lei Fengyu, Sui Guojie, Deng Liben, Zhang Tao, Liu Huan, Liu Yunyi, Pu Yongxia Innovation and practice of geology and engineering integrated fracturing technology for shale oil in Yingxiongling area in the western Qaidam Basin China Petroleum Exploration    2023, 28 (4): 105-116.   DOI: 10.3969/j.issn.1672-7703.2023.04.010 Abstract （946）   HTML    PDF （2907KB）（7）    Knowledge map    Save The limy dolomite and shale are well developed in Lower Ganchaigou Formation shale series in Yingxiongling area in Qaidam Basin, and the favorable reservoirs of limy-dolomitic flat are superimposed and interbedded with high-quality source rocks, showing huge exploration and development potential of shale oil resources. However, there are some difficulties in reservoir reconstruction, such as high field stress, high stress difference, high-frequency sedimentary cycle, well-developed lamination in vertical direction, and strong reservoir heterogeneity. Therefore, it is urgent to develop a highly applicable and high-efficiency fracturing technology system to support the benefit exploration and high-efficiency development. By conducting geomechanical experiments, the law of shale rupture and fracture propagation is clarified, and the reservoir reconstruction idea of “controlling nearby fractures and propagating long fractures” is formulated; A new algorithm of 1D geomechanics and fracability is researched, and a 3D fine geomechanical model is established; The combination of model simulation optimization and data-driven optimization is applied to form a network fracturing technology template for vertical wells; By benchmarking the mainstream practices and key parameters of volume fracturing of continental shale oil in China, the concept of geology and engineering integration is implemented in cluster setting and fracturing parameters optimization, achieving the upgrade of volume fracturing technology with the core of “high-density cutting, extremely limiting flow perforation, large displacement, large scale, high-intensity and continuous slickwater sand addition, inverse composite ‘controlling nearby fractures and propagating long fractures’, and high quartz sand percentage”. A total of 37 fracturing operations were conducted in vertical wells, with an oil rate of 2.1-44.9 m 3/d, and the wells with commercial oil flows accounted for 97.2%; Another six fracturing operations were conducted in horizontal wells, with the maximum oil rate of 113.5 m 3/d, and the proven shale oil geological reserves of 5×10 8 t in the upper member of Lower Ganchaigou Formation. Reference | Related Articles | Metrics

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Xi Shengli, Liu Xinshe, Ren Junfeng, Liu Gang, Zhang Caili, Hui Xiao, Zhao Weibo, Wang Hongwei, Jing Xianghui, Dong Guodong, Wei Jiayi, Li Han New understanding of hydrocarbon accumulation and exploration potential in risk exploration field in Ordos Basin China Petroleum Exploration    2023, 28 (3): 34-48.   DOI: 10.3969/j.issn.1672-7703.2023.03.004 Abstract （945）   HTML    PDF （1753KB）（12）    Knowledge map    Save In recent years, fruitful achievements have been obtained in petroleum exploration in Ordos Basin by innovating geological understanding,highlighting risk exploration, strengthening large-scale exploration, and focusing on benefit exploration, with annual output exceeding 60 million tons of oil equivalent during the 2020-2022, in which risk exploration has played an important role in the exploration of “four new” fields. Based on the previous research results and the deep analysis of hydrocarbon accumulation conditions of the Ordovician subsalt, limestone in the Permian Taiyuan Formation, and shale oil in the seventh member of the Triassic Yanchang Formation (Chang 7 member), the innovative understanding of hydrocarbon accumulation and technical achievements have been formed, including the “new gas-bearing system in the subsalt dolomite mound beach body within source rock”, “sandwiched hydrocarbon accumulation pattern of Taiyuan Formation limestone”, and “sweet spot evaluation standard and special reservoir reconstruction technology for the laminated shale oil in Chang 7 3 sub member”, which have grown to be the replacement fields during the 15 th Five-Year Plan period and in the medium-long term. Meanwhile, by highlighting the exploration concept of “marching towards source rocks,new fields, and deep formations”, the characteristics of hydrocarbon accumulation and exploration potential in zones with low exploration degree are re-recognized according to two levels of key research orientation and zone preparation, and the prospects and orientation of risk exploration fields in the future are proposed. Among them, the key research orientation refers to the zones that have promising signs and great resource potential, mainly including the Ordovician marine shale gas, lower combination of Yanchang Formation, tight gas in coal measures and the Proterozoic Great Wall System; While the zone preparation aims at zones with basic hydrocarbon accumulation conditions, but low research degree and high exploration difficulty, such as the Cambrian in the peripheral of the central paleo uplift, complex structural areas in the western basin margin, and new series of the third-second members of the subsalt Majiagou Formation (Ma 3-Ma 2 members) in the eastern basin. The new geological understanding, achievement summary, and potential analysis of the risk exploration fields will support to achieve the orderly replacement of exploration zones in the basin and play an important guiding role in accelerating the further strategic development of Changqing Oilfield. Reference | Related Articles | Metrics

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Fang Rui, Jiang Yuqiang, Yang Changcheng, Wang Zhanlei, Sun Shasha, Zhu Xun, Li Shun, Gu Yifan, Zhou Yadong, Liu Dongxi, Luo Yao, Luo Yuzhuo Geological characteristics of shale oil in the Jurassic Lianggaoshan Formation in Sichuan Basin China Petroleum Exploration    2023, 28 (4): 66-78.   DOI: 10.3969/j.issn.1672-7703.2023.04.007 Abstract （921）   HTML    PDF （9399KB）（69）    Knowledge map    Save In recent years, major breakthroughs have been made in the exploration of the Jurassic lacustrine shale oil in Sichuan Basin, showing great exploration potential. In order to support the further deepening exploration, the field outcrop, logging, well drilling, coring and systematic core sample experimental data are combined to analyze the geochemical characteristics, rock brittleness, pore structure and oil and gas bearing properties of shale with various lithologic combinations in the Jurassic Lianggaoshan Formation, and identify the lithologic combination types of the dominant shale. The results indicate that the lithologic combination of shale interval in Lianggaoshan Formation is classified into three categories and five types, i.e., pure shale combination, shell type shale combination, and siltstone type shale combination; Among the five types of lithologic combinations, shale is in the mature stage, but there are differences in organic matter content, type, and brittle mineral content. The shale of pure shale combination has an average TOC of greater than 1%, Type Ⅱ 1 organic matter, and brittle mineral content of higher than 52%; The organic matter characteristics of the shale of the shell type shale combination are similar to those of the pure shale combination, but the content of brittle minerals is greater than 65%; The shale of the siltstone type shale combination has an average TOC of less than 1%, Type Ⅱ 2 organic matter type, and the brittle mineral content of greater than 65%. The main reservoir space of various combinations is composed of microfractures and inorganic pores (pore diameter of 10-500 nm). The siltstone type shale combination has a larger pore throat and better pore connectivity than the pure shale combination and shell type shale combination. The free hydrocarbon content of the pure shale combination is greater than 1 mg/g, showing good oil-bearing property. OSI of the pure shale combination and the siltstone type shale combination is greater than 100 mg/g of some samples, indicating good oil movability. The comprehensive analysis shows that pure shale combination and siltstone type shale combination are favorable lithologic combination for shale oil exploration. Benefiting from the good fracability, the siltstone type shale combination is the main sweet spot for shale oil exploration in Lianggaoshan Formation. Reference | Related Articles | Metrics

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Yang Jinyu, Chen Xiaoping, Li Chao, Zheng Kui, Zhang Baojuan, Chen Chunheng Optimization of infill adjustment parameters of horizontal shale oil wells based on economic benefit evaluation: a case study of shale oil reservoir in the seventh member of Yanchang Formation in XAB Oilfield, Ordos Basin China Petroleum Exploration    2023, 28 (4): 129-138.   DOI: 10.3969/j.issn.1672-7703.2023.04.012 Abstract （919）   HTML    PDF （4434KB）（9）    Knowledge map    Save XAB Oilfield in Ordos Basin is located in Dingbian, Shaanxi Province. The main target layer is the shale interval in the seventh member of the Upper Triassic Yanchang Formation (Chang 7 member), with tight shale reservoir and high-angle fractures widely developed. Since 2011, rolling capacity construction and development by horizontal wells have been applied to produce the shale oil reservoir, which have the problem of low oil recovery degree and low production rate. In recent years, in order to research the high-efficiency shale oil development mode, tests of inter-well infill adjustment in horizontal well development zone have been conducted, and good results have been achieved in increasing oil production. Based on understanding of infill adjustment tests in the early stage, a “matrix-fracture” dual medium numerical model is established by fully considering the natural fracture features in the study area, and the infill adjustment parameters are optimized for horizontal well development zones with various production years, with the main parameters including infill timing, hydraulic fracture layout, horizontal well spacing and half-length of hydraulic fractures. A total of 76 infill adjustment schemes are designed to simulate and calculate the cumulative oil production of various schemed during the evaluation period. Furthermore, the financial net present value ratio is calculated and the economically beneficial schemes are ranked and optimally selected by using the financial cash flow method. The study results show that: (1) The longer the production period of the horizontal well development zone, the poorer results of infill wells. (2) The staggered layout pattern is better than the symmetrical layout pattern of hydraulic fractures. (3) The optimal infill adjustment parameters vary given the different infill timings. When the infill timing is 2-10 years, the optimal infill well spacing is 260 m, and the optimal half-length of the hydraulic fracture ranges in 140-180 m. On this basis, the horizontal infill adjustment design for Chang 7 member shale oil in horizontal well development zone in XBA Oilfield is conducted. After infill adjustment, the oil recovery factor and net present value ratio are expected to increase by 1.05% and 0.013 respectively, which supports to improve the shale oil development results and achieve good economic benefits. Reference | Related Articles | Metrics

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Wang Qinghua, Yang Haijun, Li Yong, Cai Zhenzhong, Yang Xianzhang, Xu Zhenping, Chen Cai, Sun Chunyan Major breakthrough in the Carboniferous-Permian in Well Qiatan 1 and exploration prospect in the piedmont southwestern Tarim Basin China Petroleum Exploration    2023, 28 (4): 34-45.   DOI: 10.3969/j.issn.1672-7703.2023.04.004 Abstract （910）   HTML    PDF （9925KB）（17）    Knowledge map    Save A major breakthrough has been made in the Carboniferous-Permian carbonate rocks in Well Qiatan 1 in Wuqia structural zone in the West Tianshan Thrust Belt, marking the discovery of a major replacement formation in the piedmont southwestern Tarim Basin. Combined with the regional geological data, studies on field outcrops, drilling, and seismic data, as well as the comprehensive analysis of laboratory experimental and test data in wells Qiatan 1 and Kuntan 1, hydrocarbon accumulation conditions in the Carboniferous-Permian in the piedmont southwestern Tarim Basin are re-recognized. The study results show that a “horseshoe-shaped” platform margin zone was developed in the Late Carboniferous-Early Permian in the piedmont southwestern Tarim Basin, and a favorable high-energy beach sedimentary facies zone was formed in belts, in which source rocks of bay lagoon facies were deposited in the Permian Qipan Formation, with a thickness of up to 500 m, type Ⅰ-Ⅱ organic matter, and high organic matter abundance. Jointly controlled by sedimentary facies and karstification, the fractured-vuggy type carbonate reservoirs were developed in the Late Carboniferous-Early Permian, forming a favorable reservoir and cap rock assemblage with the overlying thick mudstone in the Permian Qipan Formation. As a result, a new hydrocarbon accumulation pattern of “lower source rock and upper reservoir, hydrocarbon transport by fault and near-source accumulation” is established. The comprehensive analysis indicates that the fault anticline traps in the Carboniferous-Permian are distributed in rows and belts, which have the advantage of near-source hydrocarbon accumulation, and a number of favorable exploration targets such as wells Yetan 1 and Abei 1JS are optimally selected after evaluation, showing good exploration prospects, which are expected to be the major replacement field for large-scale gas exploration and discovery. Reference | Related Articles | Metrics

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Xu Changgui, Zhu Guanghui, Ji Hongquan, Zhu Yanhe, Sun Qiang Exploration progress and reserve increase strategy of onshore natural gas of CNOOC China Petroleum Exploration    2024, 29 (1): 32-46.   DOI: 10.3969/j.issn.1672-7703.2024.01.003 Abstract （900）   HTML    PDF （3098KB）（13）    Knowledge map    Save In order to achieve the rapid development of natural gas industry and increase gas production, CNOOC has gradually increased exploration investment in mining rights areas in Ordos Basin and Qinshui Basin, in which there are multiple types of natural gas including tight gas, CBM, and conventional gas, with gas resources of up to 3×10 12m 3 in the two basins and proven gas geological reserves of 7500×10 8m 3 in high-abundance and structurally simple zones. Based on a comprehensive analysis of resource potential and quality, gas accumulation conditions, and exploration technology, CNOOC has proposed a development strategy of increasing onshore natural gas reserves with a level of trillion cubic meters. The company has clarified the guiding ideology of simultaneous exploration of tight gas and CBM and stereoscopic exploration of multi type gas resources, and determined the deployment strategy of accelerating the exploration of deep CBM and tight gas in the eastern part of Ordos Basin and rapidly promoting the exploration of middle and shallow CBM in Qinshui Basin. Furthermore, the comprehensive analysis of exploration fields, gas accumulation and enrichment laws, and exploration technology research directions enables to clarify the key exploration orientations in the near future. The eastern Ordos Basin is characterized by orderly co-occurrence of full oil and gas system in coal measure strata. As a result, it is necessary to conduct exploration in the full gas accumulation system in coal measure strata, consolidate the material basis for increasing reserves and production, focus on tight gas and deep coalbed methane, research on CBM in thin cool seams, Ordovician conventional natural gas, and bauxite rock gas, and promote the simultaneous exploration and replacement of multi type gas resources by applying exploration and development integration and geology and engineering integration, so as to achieve the exploration and development of full gas accumulation system. In the northern and southern parts of Qinshui Basin, it is necessary to promote the volume fracturing of horizontal wells and production technology tests for middle and shallow CBM and popularize its application, and form complementary economic and effective development with thin CBM, so as to promote the overall increase in CBM reserves and production in Qinshui Basin. The exploration activities in the above key areas will ensure the reserve increase and healthy and stable development of large onshore gas region of CNOOC with a level of trillion cubic meters. Reference | Related Articles | Metrics

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Gu Yonghong, Zhou Changjing, Ma Zhanguo, Xiao Yuanxiang, He Ping, Cao Yujie, Yang Shangru Research and application of composite fracture network sand fracturing technology for tight limestone in horizontal well China Petroleum Exploration    2024, 29 (3): 159-169.   DOI: 10.3969/j.issn.1672-7703.2024.03.014 Abstract （877）   HTML    PDF （2968KB）（6）    Knowledge map    Save Ordos Basin has abundant natural gas resources in Taiyuan Formation limestone reservoir, which is a major replacement field for gas exploration and development in Changqing Oilfield Company. However, no gas production breakthrough has been made before by using various acid fracturing technologies due to the factors such as tight limestone, thin reservoir thickness, and fast acid-rock reaction rate. As a result, after changing idea of well stimulation technology, study on fracture propagation mechanism, research and development of support technologies of fracturing fluids and key materials, and fine characterization of volume fracturing mode have been strengthened, developing an integrated horizontal well composite fracture network sand fracturing technology with “multiple stages, less clusters, dense fractures, and composite acid-sand fracturing”. Based on the physical simulation experiments on large outcrop, and combined with geological characteristics and rock mechanic properties, the reservoir characteristics of high brittleness, low difference between the two horizontal principal stresses and well-developed natural fractures are determined, and the volume fracturing technology enables to obtain complex fracture network. By applying the double technological advantages of “deep acid fracturing + large-scale sand fracturing”, a high-conductivity fracture flow pathway with “hydraulic fracture network + acid corrosion fracture” has been constructed, which supports to significantly increase fracture volume together with densely cutting fracturing in horizontal well. In view of the limestone characteristics of high Young’s modulus, high fracture pressure, high fracture propagation pressure and low fracture width, the anti-pressure level of casing pipe has been improved and differential design of sand placement for fractures has been conducted, forming a continuous sand adding mode with multi-scale small size proppants, which solves the problem of difficult sand fracturing of reservoir with high Young’s modulus. Based on the three-level damage evaluation of matrix, wall surface and fracture, a low damage variable viscosity slick water system has been developed to propagate fractures, form fracture network and achieve sand carrying in high modulus reservoirs. This fracturing technology has been applied in four wells, obtaining an average gas rate of 59.7×10 4 m 3/d in single well, which is 5-20 times higher than that by acid fracturing in vertical well, indicating a significant increase in production. At present, the horizontal well composite fracture network sand fracturing technology has been used as the main reservoir stimulation technology for Taiyuan Formation limestone in Changqing Oilfield, which provides strong technical support for the exploration breakthrough and effective development of this type of gas reservoirs. Reference | Related Articles | Metrics

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Zhi Dongming, He Wenjun, Xie An, Li Mengyao, Liu Yin, Cao Jian Recognition and enlightenments of new oil and gas exploration fields in deep formations in Junggar Basin China Petroleum Exploration    2025, 30 (3): 1-24.   DOI: 10.3969/j.issn.1672-7703.2025.03.001 Abstract （872）   HTML    PDF （22418KB）（6）    Knowledge map    Save The deep formations in petroliferous basins have become a practical field for petroleum exploration. Junggar Basin is characterized by long tectonic evolution history and complex geological settings. Based on the exploration achievements in recent years, the new exploration fields in deep formation have been predicted, which indicates that there are four new exploration fields in the deep to ultra-deep formations, including prototype marine basin oil and gas reservoirs, intra source rock unconventional oil and gas reservoirs in the Permian Fengcheng Formation in Western Depression, large-scale stratigraphic oil and gas reservoirs in hydrocarbon-rich sags, and Jurassic–Cretaceous structural oil and gas reservoirs in the southern marginal foreland thrust belt. For prototype basin oil and gas reservoirs, controlled by the scattered source rocks in multiple depo-centers in the Carboniferous, relatively independent whole petroleum system can be formed in these source kitchens. Intra source rock oil and gas reservoirs in the Permian Fengcheng Formation in Western Depression showed a hydrocarbon accumulation pattern of orderly distribution of conventional–unconventional resources. The deep formation in Pen 1 Well West–Shawan Sag is a practical field for discovering a large gas zone with resources of trillion cubic meters. In hydrocarbon-rich sags, jointly controlled by paleogeomorphology and lake level, large-scale stratigraphic traps were formed in deep formations, and the clustered oil and gas reservoirs in trough areas are favorable targets. The large-scale structural traps were formed in the Jurassic-Cretaceous in the southern marginal foreland thrust belt, and high-quality reservoirs can still be developed below 8000 m, possessing the geological conditions for forming large-scale gas reservoirs. The study shows that the petroleum exploration in Junggar Basin has entered a new stage focusing on deep formations, generally exhibiting the coexistence of conventional–unconventional oil and gas reservoirs in sequence. The high-quality source rocks and effective hydrocarbon accumulation factors provided a solid material basis and favorable conditions for deep oil and gas reservoirs in the basin. Reference | Related Articles | Metrics

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Yang Yanhui, Wang Yuting, Liu Zhong, Chen Biwu, Wu Chunsheng, Zhang Xueying, Dong Qing Strategy and practice of high-efficiency development of high-rank coalbed methane in the southern Qinshui Basin China Petroleum Exploration    2024, 29 (4): 18-31.   DOI: 10.3969/j.issn.1672-7703.2024.04.002 Abstract （868）   HTML    PDF （6864KB）（9）    Knowledge map    Save There are abundant high-rank coalbed methane resources in China, and the high-efficiency development is of great energy, security,and ecological significances. Taking the development practice of high-rank coalbed methane in southern Qinshui Basin as an example, five main problems and challenges in the early development process are systematically analyzed: (1) A lack of advanced theory for the development of high-rank coalbed methane; (2) Low accuracy of favorable area selection; (3) Insufficient adaptability of reservoir reconstruction technology; (4) Low efficiency and poor benefit of drainage-production control regime; (5) “Three difficulties” and “three highs” of the gathering and transportation system. PetroChina Huabei Oilfield Company has adhered to problem-oriented and target-oriented approach and integrated indoor research and field practice, forming a new concept and key technologies for the high-efficiency development of high-rank coalbed methane, which include a drainage development concept, and a development mode of single-lateral horizontal well casing + multistage fracturing; The technology for optimal selection of high-yield favorable areas has been researched, achieving the transformation from large-area overall production capacity construction to precise construction mode in the favorable area; The fracturing and reservoir stimulation technology for coalbed methane has been improved and updated, which supports to form multi-level effective fracture network; The optimal,fast and high-efficiency drainage-production control technology has been innovated; The low-pressure ring surface gathering and transportation technology has been developed to achieve high benefits. The field practice shows that the success rate of new constructed production capacity has increased from 37% to higher than 84%, the average daily gas production of a single well has increased by 1.6 times, the time reaching target production has decreased by more than 20%, and the cost of surface construction investment for new projects has reduced by 20%. In addition, the coalbed methane production breakthrough has been achieved in all types of reservoirs in Qinshui Basin, with an annual production capacity of 21×10 8 m 3 in coalbed methane field in the southern Qinshui Basin, which is it the largest coalbed methane field in China, greatly boosting the strategic development of coalbed methane. Reference | Related Articles | Metrics

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Lu Zhiyong, Liu Li, Jiang Yuling, Zhang Qian, Zhan Xiaohong, Xiao Jialin Practice of geology and engineering integration in the stereoscopic development of Fuling Gas Field China Petroleum Exploration    2024, 29 (3): 10-20.   DOI: 10.3969/j.issn.1672-7703.2024.03.002 Abstract （860）   HTML    PDF （3555KB）（8）    Knowledge map    Save In view of the insufficient utilization of residual gas reserves by primary well pattern development in Fuling Shale Gas Field, geology and engineering integrated stereoscopic development technology is the core means to improve gas recovery and achieve accurate utilization of residual gas reserves. As a result, a new high-efficiency shale gas development mode with geology and engineering integration has been established, and shale gas modeling and simulation integrated technology has been innovatively developed to conduct fine research and identify the distribution of residual shale gas; The coupling of geological and engineering double sweet spots enables to determine the gold target window of well drilling trajectory, and the classification standard system of “resource + stress + natural fracture” three-in-one layered benefit combination has been established; Based on the differential distribution pattern of residual gas, the drilling and fracturing optimization design process has been established with “geology-drilling-fracturing-surface collaborative optimization”; By using real-time monitoring, the dynamic adjustment of well drilling trajectory and fracturing construction has been conducted, and integrated data sharing platform and real-time decision system have been constructed. The geology and engineering integrated stereoscopic development technology has guided the development of Jiaoshiba block and increased estimated recovery rate from 12.6% to 23.3%, and up to 39.2% in the stereoscopic development zone. The application of this technology supports to reduce shale gas drilling and production investment, and billion square meter production capacity construction investment and development costs year by year, which effectively guides the recovery enhancement and high-efficiency development of Fuling Shale Gas Field. Reference | Related Articles | Metrics

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Zheng Majia, Guo Xingwu, Wu Ya, Zhao Wentao, Deng Qi, Xie Weiyang, Ou Zhipeng Cultivation practice and exploration breakthrough of geology and engineering integrated high-yield wells of ultra-deep shale gas in the Cambrian Qiongzhusi Formation in Deyang-Anyue aulacogen, Sichuan Basin China Petroleum Exploration    2024, 29 (3): 57-67.   DOI: 10.3969/j.issn.1672-7703.2024.03.006 Abstract （852）   HTML    PDF （6115KB）（8）    Knowledge map    Save The ultra-deep shale gas reservoir in the Cambrian Qiongzhusi Formation in Deyang-Anyue aulacogen in Sichuan Basin is characterized by old geologic age, large burial depth and high thermal evolution, leading to great difficulty in shale gas exploration and development. However, there is no direct experience to learn from both at home and abroad. In view of this, the idea of geology and engineering integration is applied to preliminarily establish the key technological system of “well deployment-drilling-fracturing-production” for cultivating high-yield wells of Qiongzhusi Formation shale gas: (1) Integrated well deployment. The understanding of “hydrocarbon accumulation controlled by aulacogen” is deepened, the distribution mode of high-quality reservoir is determined, and the technical limits for operating high-yield wells are clarified, supporting the optimization of well deployment. (2) Integrated drilling, logging, and geosteering. Based on the comprehensive evaluation of geological and engineering parameters, the optimum drilling target is selected, the well trajectory is optimized, and the geology and drilling integrated fine management is strengthened, which effectively guarantee the drilling rate of high-quality reservoir. (3) Integrated fracturing and reservoir stimulation. The integrated fracturing model is used to optimize fracturing design, forming fracturing technology of “promoting fracture complexity + expanding fracturing volume + highly fracture supporting + casing deformation prevention”, which effectively achieves the uniform fracture initiation, high-efficiency fracture propagation, full reservoir support and maximum reservoir stimulation volume. (4) Integrated fine management of flowback. The “four-factor” flowback and reservoir stimulation technology is developed, and the fine flowback and production analysis platform is established, which achieve the “double breakthroughs” of reservoir damage reduction and gas well stimulation. By using the above technology system, high-yield gas flow has been obtained in Well Zi 201 for the first time in China in the Cambrian shale reservoir with a depth of greater than 4500 m, and the replication of high-yield production has successfully been achieved in Well Weiye 1H, which support to initially identify a favorable area of nearly 3000 km 2 with the depth of shallower than 5000 m and gas resources of nearly 2×10 12 m 3. The high-yield well cultivation technology and method lay a solid foundation for solving difficulties in large-scale and high-efficiency development of ultra-deep shale gas in the Cambrian Qiongzhusi Formation. Reference | Related Articles | Metrics

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He Xiao, Liang Feng, Li Hai, Zheng Majia, Zhao Qun, Liu Yong, Liu Wenping Breakthrough and enrichment mode of marine shale gas in the Lower Cambrian Qiongzhusi Formation in high-yield wells in Sichuan Basin China Petroleum Exploration    2024, 29 (1): 142-155.   DOI: 10.3969/j.issn.1672-7703.2024.01.011 Abstract （829）   HTML    PDF （10131KB）（20）    Knowledge map    Save Small progress has been made in the exploration and development of shale gas in the Lower Cambrian Qiongzhusi Formation over the years. The high-yield gas flow in Well Zi 201 has greatly increased confidence in the large-scale and commercial development of shale gas in Qiongzhusi Formation. The different enrichment laws in various areas and layers and the optimal selection of favorable areas are the primary problems to be solved for shale gas development. Based on the analysis of paleontology, sedimentary facies, and reservoirs in 57 wells in Sichuan Basin, the theoretical basis for the deployment of Well Zi 201 and enrichment conditions of shale gas in Qiongzhusi Formation are analyzed in detail, and the exploration and development orientation are pointed out. Firstly, a stratification standard for Qiongzhusi Formation is established. It is clarified that four sets of organic rich shale of deep shelf facies were developed in Qiongzhusi Formation (layers ①, ②, ③, and ④), which were controlled by the development of rift troughs, with the largest shale thickness in the trough. The characteristics of shale reservoirs are analyzed, which indicate that the reservoir pressure, porosity, and gas saturation show an increasing trend from bottom to top, and from the outside to the inside of the rift trough, and reservoir overpressure plays an important role in the preservation of shale pores. On this basis, an overpressure and differential shale gas enrichment mode of “different facies in multiple layers and overpressure pore preservation” in Qiongzhusi Formation has been established, and it is pointed out that the overpressure pore development area (interval) far away from the dispersion pathway is the favorable area (interval) for shale gas enrichment. Finally, the study results indicate that Well Zi 201 and its surrounding areas are the main areas for increasing shale gas reserves and production in the future, with resources of 8.06×10 12m 3. It shows considerable development potential in western Sichuan Basin, with resources of 0.72×10 12m 3. Affected by graphitization and tectonic activities, areas with overpressure pore development far from weathered crust and surface outcrops are favorable for shale gas exploration in Changning in southern Sichuan Basin and northern Guizhou Province. Reference | Related Articles | Metrics

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Yang Yuran, Shi Xuewen, Li Yanyou, He Yifan, Zhu Yiqing, Zhang Ruhua, Xu Liang, Yang Xue, Yang Yiming, Zhang Yichi Paleogeomorphology, sedimentary patterns and exploration of Deyang Anyue Rift Trough in Qiongzhusi Formation, Sichuan Basin China Petroleum Exploration    2024, 29 (6): 68-81.   DOI: 10.3969/j.issn.1672-7703.2024.06.006 Abstract （816）   HTML    PDF （33496KB）（16）    Knowledge map    Save The shale gas within the Deyang-An’gue sag, specifically in the Qiongzhushi Formation, exhibits significant exploration potential. The characterization of the sag’s depositional features during the sedimentary period of the Qiongzhushi Formation has not been systematically understood. By establishing a sequence stratigraphy framework for the deposition of the Qiongzhushi Formation and analyzing sedimentary landforms based on shale thickness and quality, the geological significance of shale gas is elucidated. The results indicate that, considering sedimentary landforms, sedimentary facies, shale thickness, etc., the sedimentary period of the Qiong 1-2 sub-section can be divided into three landform units: intra-sag, slope, and extra-sag. Ancient landforms and source materials jointly control the shale thickness and quality. The intra-sag unit develops a siliceous mud-shale microfacies, with a shale reservoir thickness exceeding 20 m. The slope unit develops (including) sandy mud-shale microfacies, with a shale reservoir thickness of 5 to 20 m. The extra-sag unit develops muddy sandy-shale microfacies, with a shale reservoir thickness less than 5 m. Reference | Related Articles | Metrics

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Chen Xuan, Liu Juntian, Zhang Hua, Lin Tong, Gou Hongguang, Cheng Yi, Guo Sen Accumulation Conditions of Deep tight sandstone Gas in Taipei Sag and Enlightenment and Significance of Exploration and Discovery of Yuetan 1H Well China Petroleum Exploration    2024, 29 (6): 1-16.   DOI: 10.3969/j.issn.1672-7703.2024.06.001 Abstract （816）   HTML    PDF （7576KB）（14）    Knowledge map    Save Well Yuetan 1H in the Taipei Sag of the Tuha Basin made the first exploration discovery in the Badaowan Formation of the Xiaocaohu sub-sag, which achieved a comprehensive breakthrough in the exploration of the secondary sag area of the Taipei Sag and revealed the good exploration prospect of tight sandstone gas in the entire Taipei Sag area. Based on the Taipei Sag, this paper comprehensively analyzes the geological conditions of deep tight sandstone gas formation, and concludes that: (1) the development of three sets of source rocks in the Shuixigou Group provides a sufficient material basis for tight sandstone gas; (2) The development of delta front-scale sand bodies and near-coal seam sandstone dissolution pores are favorable reservoirs for deep tight gas accumulation; (3) The strata located in the lower part of the strike-slip thrust zone have good preservation conditions, which is a favorable area for tight sandstone gas enrichment. At the same time,based on the geological information obtained from the exploration and discovery of Well Yuetan 1H, the dominant accumulation conditions of Xiaocaohu sub-sag were clarified, and then the favorable geological conditions of tight gas in the entire Taipei Sag were re-understood, and it was pointed out that: (1) effective sand bodies were developed in the central area of the sub-sag; (2) The physical properties of the reservoir of the southern source sand body are better; (3) The source rock development zone with higher maturity is a favorable zone for natural gas enrichment. Based on the latest geological information and understanding, the evaluation of tight gas resources in Taipei Sag was re-carried out, and the predicted tight sandstone gas resources were 7070×10 8m 3, which was significantly higher than that in the previous period. Finally, the comprehensive evaluation selects two favorable exploration areas of tight sandstone gas in the northeast of Xiaocaohu sub-sag and north of Shengbei sub-sag. Reference | Related Articles | Metrics

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Xue Yong’an, Yang Haifeng, Huang Zhi, Xu Chunqiang, Xu Peng, Li Long New recognition of hydrocarbon accumulation and enrichment and discovery of large-scale oil and gas fields in Bohai Sea area, Bohai Bay Basin China Petroleum Exploration    2025, 30 (1): 56-67.   DOI: 10.3969/j.issn.1672-7703.2025.01.005 Abstract （811）   HTML    PDF （1605KB）（31）    Knowledge map    Save In response to the challenges of almost all large-sized structural traps being discovered and insufficient resource replacement of production oil fields in Bohai Bay Basin. In the past 20 years, the continuous research has been conducted in exploration fields of the shallow Neogene and deep buried hills by using abundant geological, well drilling, laboratory test and seismic data, forming new geological understanding of hydrocarbon accumulation controlled by “convergence ridge” and “gas generation in lake basin”, respectively. The core of hydrocarbon accumulation controlled by “convergence ridge” includes that: (1) The configuration between “convergence ridge” and fault controlled the differential hydrocarbon enrichment outside source rock; (2) The “dendritic” type large-scale lithologic traps were developed in shallow loose sandstone; (3) The concealed faults controlled by weak tectonic activity enabled to form large-scale “concealed” traps. The main connotation of “gas generation in lake basin” refers to: (1) The late rapid subsidence of Bozhong Sag caused explosive gas generation of Shahejie Formation source rock; (2) The tectonic stress controlled the development of double-layer stereoscopic reservoirs in the Archeozoic granite buried hills; (3) The rapid and high-intensity charging of early oil and late gas and dynamic accumulation occurred under the background of overpressure dynamic sealing. The above understanding has guided the discovery of 18 large and medium-sized high-yield oil and gas fields such as KL10-2 and BZ19-6, which not only facilitates the strategic shift of oil exploration towards hidden oil reservoirs in Bohai Sea area, but also achieves the strategic breakthrough in large gas fields in oil-type basin. Reference | Related Articles | Metrics

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Luo Di, Li Li, Ma Fengyuan, Xie Mingying, Feng Shasha, Weng Heng, Gao Yang, Zhang Shicheng Practice and understanding of geology and engineering integrated reservoir fracturing in offshore low-permeability oilfield: a case study of Lufeng Sag in Pearl River Mouth Basin China Petroleum Exploration    2024, 29 (3): 103-116.   DOI: 10.3969/j.issn.1672-7703.2024.03.010 Abstract （811）   HTML    PDF （13488KB）（10）    Knowledge map    Save Pearl River Mouth Basin is a major area for the accumulation of low-permeability oil and gas reservoirs with huge resources in the offshore China. L44 Oilfield in Lufeng Sag is the first integral low-permeability oilfield that have been fractured and developed in the eastern South China Sea. However, problems such as insufficient scale of reservoir reconstruction and unclear understanding of fracture initiation mechanism occur after fracturing. Based on seismic interpretation, logging and geological data, a geology and engineering integrated modeling method for offshore low-permeability oilfield has been established, which enables to more accurately predict fracture propagation. In addition,3D geomechanical modeling has been conducted and geological/engineering double sweet spots have optimally been selected in the study area.The upper limit of reservoir perforation interval applicable for offshore low-permeability oilfield has been proposed in fracturing design, and the new fracturing scheme design and capacity simulation have been conducted for Well C3, showing a basically consistent production level with the expectation after the secondary fracturing. The study results show that: (1) Given a low displacement, when the length of perforation interval increases from 4 m to 16 m, the fracture length in a stage decreases by 30 m on an average, and the cumulative production capacity of a single well decreases by 88% in the first five years; (2) An increase in the length of perforation interval inhibits the scale of reservoir reconstruction. When the perforation interval is more than 6 m, the scope of reservoir reconstruction greatly decreases; When the perforation interval is less than 6 m, the scope of reservoir reconstruction insignificantly decreases; As a result, the optimal length of perforation interval should be no more than 6 m; (3) Given a perforation interval of less than 6 m, the average reservoir reconstruction volume increases by 10.97% when the construction displacement increases by 1 m 3/min. A higher construction displacement enables to further increase the reservoir reconstruction volume. The geology and engineering integrated modeling method for offshore low-permeability oil fields provides a new idea for the development plan and fracturing scheme design of low-permeability oilfields in the eastern South China Sea, which is beneficial for improving development benefits of oilfields. Reference | Related Articles | Metrics