The development of laminae is one of the typical characteristics of continental shale in faulted lake basins in eastern China. Three sets of shale layers were developed in the second member of the Paleogene Kongdian Formation (Kong 2 member), the third member of Shahejie Formation (Sha 3 member) and the first member of Shahejie Formation (Sha 1 member) in Huanghua Depression, Bohai Bay Basin, which were deposited in different sedimentary environments, thus forming different laminae units. The oil-bearing property, reservoir storage capacity and fracability vary, which restricts the exploration and development achievements of shale oil. Based on core samples, wireline logging and mud logging data of three sets of shale layers in Huanghua Depression, basic geochemical and rock mineral analysis has been conducted, and multi-scale fine characterization on various types of shale laminae has been implemented by comprehensively using technical measures such as AMICSCAN mineral scanning, high resolution scanning electron microscopy, energy spectrum elements, micro-CT scanning, and true triaxial hydraulic fracturing simulation, clarifying the depositional environment, reservoir storage capacity, flow capacity and fracability of different types of laminated shale. The study results show that Kong 2 member shale is mainly composed of felsic shale, as well as mixed shale and a small amount of limy-dolomitic shale; Sha 3 member shale is dominated by mixed shale, with felsic shale; Sha 1 member shale is mainly mixed shale, with a small amount of limy-dolomitic shale and felsic shale. The felsic laminae are mainly observed in Kong 2 member shale, with a small amount of limy-dolomitic laminae and clay laminae. The limy-dolomitic laminae and clay laminae are dominant in Sha 3 member shale, with a small amount of felsic laminae. While the dolomitic laminae are dominant in Sha 1 member shale, with a small amount of felsic laminae and clay laminae. The clay laminae generally have high organic matter content, and are responsible for hydrocarbon generation in the microscopic source rock–reservoir system, which lays a foundation for shale oil enrichment. The felsic laminae and limy-dolomitic laminae usually have high storage capacity, serving as the reservoir part in the microscopic source rock–reservoir system, providing reservoir and storage space for shale oil. Compared with layered and massive shale, shale reservoirs with high-frequency lamination have larger specific surface area, larger area for hydrocarbon charging, better pore connectivity, and an overpressure state due to the constant hydrocarbon generation and pressurization. In addition, the micron-scale dissolution pores of feldspar and dolomitic minerals were formed by organic acids in the process of hydrocarbon generation, which improved physical properties of shale reservoirs. The physical fracturing simulation experiments show that the laminated felsic shale has the best fracturing effect, followed by the laminated mixed shale, while the massive limy-dolomitic shale has the poorest fracturing results.

The newly revised “Mineral Resources Law of the People’s Republic of China” in 2024 (hereinafter referred to as the “New Mineral Resources Law”) has made systematic and reconstructive modifications to the approach of mineral resources management, which has established a whole-chain management system of mineral resources including mining rights, mineral resource exploration and exploitation, ecological restoration of mining areas, mineral resource reserves and emergency, and supervision and administration. Based on a systematic review of the legal provisions related to oil and gas in the New Mineral Resources Law, the content of the provisions has been interpreted from five aspects, i.e., the special protection system for strategic mineral resources, the management model of mining rights transfer registration and administrative licensing, key systems for mining rights management, policy support for exploration and exploitation, and the fulfillment of mining rights holders’ obligations. Meanwhile, the impact of these systems mentioned above on oil and gas mining rights holders has been analyzed. After investigation and data analysis, it is proposed that under the New Mineral Resources Law, oil and gas mining rights holders should implement the special protection system for strategic mineral resources, timely transform the management ideas of oil and gas mining rights transfer, registration, and licensing, properly grasp the key systems of oil and gas management, utilize the supporting policies for oil and gas exploration and exploitation, fulfill the obligations of oil and gas mining rights holders, and promptly offer countermeasures and suggestions for the promulgation of the mineral resources law and regulations.

After over a decade of persistent efforts, preliminary technological iteration and sustained production growth have been obtained in shale gas exploration and development in China. However, it still faces scientific and technological challenges in realizing the large-scale and beneficial development. In order to advance the beneficial shale gas development and achieve “China’s Shale Gas Revolution”,  comparative analysis of shale gas geological characteristics and development methods between Southern Sichuan Basin and the United States has been conducted, and future development direction of shale gas in China has been clarified. The study results indicate: (1) Affected by multi-stage tectonic events, shale gas reservoirs in Southern Sichuan Basin are characterized by complex structure, great stress difference, and high reservoir heterogeneity. Despite its superior organic matter abundance (TOC) and maturity, critical parameters including porosity, permeability, and single-well controlled reserves are poorer than those in typical U.S. shale gas fields, posing inherent constraints to the large-scale and beneficial gas development. (2) Although the U.S. “horizontal drilling + volume fracturing” system offers valuable references, it is infeasible for direct replication. In response to the complex geological conditions in China, oil companies should overcome technical barriers in sweet spot delineation, ultra-long horizontal well drilling, and high-efficiency fracturing technology, and construct a technological system adapted to the native geological and engineering conditions. (3) The core factor for successful shale revolution in the U.S. lies in project-based management and day-rate contracting system, which achieves high-efficiency iteration given the high-risk conditions. In contrast, China’s traditional “relay-style” management mode severely impedes operational efficiency, so it is urgent to promote the flattened project system reform to stimulate management efficiency. Recent field practices in Southern Sichuan Basin show that the “China’s Shale Gas Revolution” is imperative for high-quality development, which demands establishing a tailored management system with operational autonomy, pursuing innovation aligned with China’s geological realities, and prioritizing geological–engineering sweet spot characterization, technological iteration, and stereoscopic development pilots to achieve a second leap in the development of shale gas industry in China.

The tight gas discoveries have been made in Benxi Formation and Taiyuan Formation in Shenfu block, Ordos Basin. A better understanding of reservoir characteristics and the main controlling factors is of great significance for the high-efficiency development of coal measure tight sandstone gas. Based on petrology, cast thin section, scanning electron microscopic imaging and high pressure mercury injection test methods, the rock types, reservoir physical properties and diagenesis of tight sandstone reservoirs in Taiyuan Formation–Benxi Formation in Shenfu block have been analyzed, and the main controlling factors affecting reservoir development have been discussed. The study results show that the reservoir lithology of Benxi Formation and Taiyuan Formation is mainly composed of quartz sandstone, lithic quartz sandstone and feldspar lithic sandstone. The main reservoir space types include intragranular dissolution pores, intergranular dissolution pores, intercrystal pores, matrix dissolution pores and micro-fractures, followed by primary residual pores, and the throats are mostly fine–medium throats. Compaction and partial cementation had destructive effects on sandstone reservoirs, while dissolution, tectonic activities and chlorite film had constructive effects. The development of sandstone reservoirs in Taiyuan Formation–Benxi Formation was significantly controlled by sedimentary microfacies. The delta underwater distributary channel and tidal channel microfacies were conducive to the development of high-quality reservoirs, and the physical properties of tight sandstone reservoirs were further improved by lithic dissolution, micro-fractures generated by tectonic activities and chlorite films. The high-quality reservoir sand bodies are mainly distributed in the southeastern Xiejiapu and the southern Langanpu areas with underwater distributary channels and tidal channels developed.

The deep paleo uplifts in Persian Gulf Basin controlled the development of giant low-amplitude anticlines, which further controlled the formation of world-class large oil and gas fields. It is urgent to delineate the distribution of deep paleo uplifts and faults, and analyze their control over oil and gas distribution. Based on the wavelet analysis of high precision EGM free air gravity data, 36 paleo uplifts have been identified in Central Arabian, Rub’ al-Khali and Zagros sub-basins, which are classified into three stages based on their formation and evolution processes, i.e., Precambrian, Late Devonian–Early Carboniferous, and Miocene–Pliocene. The first and second stages of paleo uplifts controlled the development of the Precambrian–Devonian anticlinal traps, the Devonian truncated unconformity–lithologic traps, and the Periman–Cretaceous anticlinal traps. While the third stage of paleo uplifts controlled the development of the Miocene–Pliocene drape anticlinal traps. By combining with the configuration relationship of hydrocarbon accumulation conditions in Persian Gulf Basin, favorable exploration areas have been predicted, including 16 oil and gas reservoirs in the Paleozoic, 26 oil and gas reservoirs in the Jurassic and 16 oil and gas reservoirs in the Cretaceous. This study provides reference for deep oil and gas exploration in Persian Gulf and similar basins.

Significant progress has been made in the exploration and development of continental shale oil in China, which has become a major field for increasing oil reserves and production. In order to investigate continental shale lithofacies and reservoir pore development characteristics and their influencing factors, two main types of shale have been studied and compared, including the mixed shale in the Lower sub-member of the third member of Shahejie Formation (Lower Sha 3 sub-member) in Bonan subsag in Jiyang Depression and the second member of Funing Formation (Fu 2 member) in Gaoyou Sag in Subei Basin, as well as the matrix shale in Dongyuemiao member and the second member of Lianggaoshan Formation (Liang 2 member) in Fuxing area in Sichuan Basin. Based on core observation and description, multiple experimental and testing techniques such as bulk rock mineral X-ray diffraction, thin section, micro area XRF, high-pressure mercury injection–low-temperature nitrogen adsorption joint measurement, micro CT, argon ion polishing scanning electron microscopy, and overburden porosity have been used to comprehensively characterize and analyze the lithofacies and reservoir pores of continental shale, and identify influencing factors for reservoir pore development. The study results indicate that multi-component and multi-scale sedimentary structures were developed in continental shale. Controlled by the alternating input of terrestrial and endogenous materials, the sedimentary structure combination types and lithofacies types of mixed shale are more abundant and diverse than the matrix shale. In Bonan subsag, the lithofacies is mainly composed of layered carbonate mixed shale, layered felsic mixed shale, laminated carbonate shale, and massive carbonate shale. In Gaoyou Sag, it is mainly composed of laminated felsic mixed shale, laminated carbonate shale, layered felsic shale, and massive clayey mixed shale. In Fuxing area, it is mainly composed of massive clayey shale, laminated shell carbonate shale, or laminated felsic shale. Based on the differences in pore carriers, the pore classification scheme for continental shale oil reservoirs has been established, proposing that pores can be formed in various inorganic minerals and organic matter components in continental shale, with the most favorable pore carriers of carbonate minerals and clay minerals. In Bonan subsag, pores are dominated by carbonate mineral pores. In Gaoyou Sag, they are mainly carbonate mineral pores and felsic mineral pores. In Fuxing area, pores are mainly clay mineral pores and carbonate mineral pores. The high-quality lithofacies was the foundation for pore development, and differences in mineral composition, structure, and sedimentary structures all affected the degree of pore development. The pores were well developed in massive clayey (mixed) shale and laminated carbonate (mixed) shale, fairly developed in laminated (layered) felsic (mixed) shale, but poorly developed in massive carbonate (mixed) shale; The diagenetic type and evolutionary sequence were key factors controlling the formation and preservation of reservoir pores. The rigid mineral particles were stacked in layers or locally mixed to form anti compaction support structures, which were beneficial for pore preservation, while the common pore increasing process included clay mineral transformation and carbonate mineral dissolution. In Bonan subsag and Gaoyou Sag, inorganic pores in mixed shale were mainly controlled by compaction, recrystallization, and dissolution, but there were basically no organic matter pores; In Fuxing area, the inorganic pores of matrix shale were controlled by compaction, clay mineral transformation, and shell calcite dissolution, and organic matter pores were developed in bitumenite.

Qingshankou Formation shale oil in Gulong Sag in the northern part of Songliao Basin (referred to as Gulong shale oil) exhibits distinct microscopic migration and differential accumulation characteristics, which affect the distribution and enrichment of retained movable hydrocarbons. The geochemical characteristics of washing oil products and pore structure of sealed and pressurized core sequences from key wells in deep lake area have been systematically tested to clarify the micro distribution characteristics of hydrocarbons and reveal the migration and accumulation mechanism of Gulong shale oil. The study results suggest that Gulong shale in the deep lake area has a grain size of smaller than 63 μm, and four lithofacies are subdivided, i.e., layered clayey shale, laminated mixed shale, laminated felsic shale, and layered calcareous shale. Based on the ranking of shale retention hydrocarbon content, the layered clayey shale with high TOC (>2%) has a high total hydrocarbon content (2.8–13.7 mg/g), and the movable hydrocarbon (2.8–12.5 mg/g) mainly occurs in intercrystal pores of clay minerals smaller than 32 nm. The laminated mixed and felsic shale with medium–high TOC (>1%) has a total hydrocarbon content of 3.8–7.3 mg/g, and the movable hydrocarbon (2.7–6.4 mg/g) mainly occurs in pores with diameters smaller than 8 nm and larger than 64 nm in the mixed laminae. The laminated felsic shale with low TOC (<1%) contains only a small amount of movable hydrocarbon (3.1–4.6 mg/g), mainly occurring in pores with a diameter greater than 64 nm and only a small amount in pores less than 8 nm. The distribution of organic matter laminae and later diagenesis are the key factors for the differential hydrocarbon distribution and accumulation. The organic matters were enriched in clayey laminae, and the generated hydrocarbon was preferentially retained in situ in organic matter pores and clay intercrystal pores. Part of the movable hydrocarbon migrated to felsic laminae or carbonate mineral laminae within source rocks. In areas with strong dissolution and well-developed pores, the movable hydrocarbon migrated on a large scale. While in areas with strong clay and carbonate rock cementation and undeveloped pores, the migration amount of movable hydrocarbon was small. Based on the movable hydrocarbon distribution and accumulation mechanism of Gulong shale oil, it can be further clarified that the high-TOC layered clayey shale has a high oil content but small pore size, which is a resource sweet spot, but the low-TOC laminated felsic shale has a low movable oil content; The medium-high TOC laminated mixed shale and felsic shale have a high movable oil content, large pore size and good fracability, which is the resource and engineering dual sweet spot.

In the southwestern margin of Ordos Basin, progradation seismic reflection features of Yanchang Formation are extensively observed in 3D seismic profile. By comprehensively using geological data such as well drilling, logging, and core section, well–seismic data has been combined to conduct stratigraphic correlation and division, and analyze the sedimentary evolution of progradation layer, sand body distribution, and oil and gas distribution laws. The following understanding has been obtained: (1) Multi-stage progradation reflection features are observed in the seventh–third members of Yanchang Formation in the southwestern basin margin, which generally reflect the progradation characteristics of water regression and sand progradation. The deposition units are stacked in a tangential oblique pattern towards the lake basin center. After reconstructing a stratigraphic framework of Yanchang Formation, the traditional method of “isopachous” stratigraphic correlation has been changed; (2) The distribution characteristics of the two types of sand bodies in the southwestern basin margin were mainly controlled by the basin bottom shape. The comprehensive study of logging, seismic, and sedimentary facies shows that the upper and lower sections of the progradation layer in Yanchang Formation respectively controlled the distribution of delta front and gravity flow sand bodies, among which the gravity flow sand bodies are favorable reservoir types for large-scale exploration and development; (3) Based on the “two-wide and one-high” seismic information, the distribution of multi-stage deep-water gravity flow sand bodies in the progradation layer has been finely characterized, effectively identifying the distribution range of high-quality reservoirs, and determining that the slope foot sand-rich belt is a favorable area for increasing tight oil reserves on a large scale. The reservoir prediction method based on seismic progradation reflection structure analysis has important guiding significance for the exploration and development of tight oil with similar deep-water sedimentary backgrounds in China.

The Ediacaran represented a key period of paleo ocean and paleoclimate evolution, and the extensively developed fibrous dolomites provided important evidences for reconstructing the oceanic chemical characteristics in this stage. The genetic types and discrimination criteria of fibrous dolomite have been discussed, focusing on the distribution, genetic mechanism, and paleo environmental significance of the Ediacaran fibrous dolomite in China. Multidimensional properties such as petrological characteristics, crystallographic properties, and geochemical composition are important criteria for identifying the dolomite genesis. The primary fibrous dolomites are typically characterized by fibrous structure, and length-slow optical properties, with well-developed growth girdles. While the secondary metasomatic fibrous dolomites commonly show acicular, botryoidal patterns or square terminations, with length-fast optical properties, but underdeveloped growth girdle. In addition, trace element content to some extent provides indicative significance in distinguishing genetic types of dolomites. Multiple types of fibrous dolomites have been identified in the Ediacaran base (first member of Doushantuo Formation) and top (second and fourth members of Dengying Formation) in Yangtze Plate, as well as in the upper Qigebulake Formation in Tarim Basin, including bladed dolomite, fascicular–length-fast dolomite, radial–length-fast dolomite, fascicular–length-slow dolomite and radial–length-slow dolomite. The former three types were mainly generated by secondary metasomatism of aragonite or high magnesium calcite, while fascicular–length-slow dolomite and radial–length-slow dolomite were more likely to be primary dolomites directly precipitated from paleo seawater or marine pore water. In the Ediacaran, seawater was featured by high Mg/Ca ratio, elevated alkalinity and low sulfate concentration, promoting the precipitation of fibrous aragonite and high magnesium calcite precursors. Evaporation further increased the Mg/Ca ratio, while metabolism of sulfate reducing bacteria in hypoxic environments released Mg2+ and increased pH and alkalinity, which effectively overcame precipitation barriers, thereby facilitating the nucleation of primary fibrous dolomites. In summary, the Ediacaran fibrous dolomites in China generally recorded critical geochemical signatures of contemporaneous seawater or marine pore water, and in some cases reflected the involvement of hydrothermal fluids. Their geochemical information effectively reveal the redox state, provenance, and temporal–spatial evolution of the Ediacaran ocean, offering critical geological evidence for reconstructing the Precambrian oceanic chemical system and assessing its environmental constraints on early life evolution.

Oil and gas production forecast is a critical technical approach for optimizing development strategy and enhancing recovery factor of oil and gas fields. The theoretical system of oil and gas production decline has systematically been reviewed, and a comparative evaluation between conventional empirical models and analytical methods has been conducted in terms of their theoretical foundations, applicability, and limitations. In addition, innovative application of machine learning in production forecast of complex reservoirs has been discussed in detail. The analysis results show that: (1) Traditional methods show robustness for conventional reservoirs but exhibit constrained application performance in unconventional oil and gas reservoirs due to strong heterogeneity and nonlinear multiphase flow; (2) The data-driven models demonstrate superior prediction performance for unconventional reservoirs through automated feature extraction and spatiotemporal correlation modeling; (3) The physical-informed hybrid models effectively integrate data-driven advantages with physical mechanisms, delivering enhanced reliability in complex conditions and long-term production forecast. The study concludes that artificial intelligence significantly improves prediction accuracy and reliability in oil and gas production forecast, with machine learning and deep learning offering novel technical support for complex reservoir development. However, challenges persist in engineering applications, particularly in real-time computation and model interpretability, where further interdisciplinary research is needed on artificial intelligence and oil and gas domain to promote intelligent and high-quality development of the oil and gas industry.

There are a series of problems of tight sandstone reservoirs in Ordos Basin, such as poor physical properties, large burial depth, high clay mineral content, and great difficulty in post-fracturing backflow. CO₂ fracturing has advantages such as reducing rock fracture pressure, reducing fluid loss and promoting backflow, which is a targeted measure for reservoirs with poor physical properties, high clay content and low pressure coefficient. Therefore, based on the true triaxial simulation of tight sandstone fracturing reconstruction process with three different injection methods, i.e., CO₂ prepad, CO₂ foam injection, and CO₂ associated injection, the variation law of core fracture pressure and fracture distribution characteristics of tight sandstone reservoirs have been analyzed through similarity criterion, and the difference in core fracturing results has been compared. In addition, Petrel geological–fracturing integrated platform has been applied to conduct numerical simulation of reservoir fracture propagation with different CO₂ injection modes. The quantitative experimental analysis results show that the ranking of fracturing effects is as follows: hydraulic fracturing for rock breaking > CO₂ foam > CO₂ associated injection > CO₂ prepad. Compared with hydraulic fractures, fracture network is the most complex by using CO₂ prepad fracturing, followed by CO₂ foam, and it is the poorest by CO₂ associated injection, which is consistent with numerical simulation results. Furthermore, the variation law of reservoir fracture network parameters with fracturing operation parameters given the different injection methods has been clarified, and a fracturing parameter optimization plate has been prepared. The new understanding provides operational guidance and suggestions for the beneficial development of tight sandstone reservoirs.

The shallow weakly consolidated strata in Bohai Sea area are characterized by new sedimentary age and poor diagenesis, resulting in loose and unformed core samples, and difficulty in conducting conventional rock mechanical tests, which is not conducive to the targeted drilling design in shallow sections. Through comprehensive mineral characterization, physical simulation experiments, and digital core modeling, the mechanical properties and failure mechanisms of shallow strata have systematically been analyzed. By using XRD testing, casting thin section analysis, and nanoindentation technology, the results show that montmorillonite accounts for 48.57% of the clay minerals in the formation, with strong water sensitivity, poor cementation degree, and well developed pores of rock samples. Physical simulation experiments indicate that as the water cut increases from 20% to 30%, the compressive strength of the rock sample decreases from 1.68 MPa to 0.41 MPa, the elastic modulus decreases from 22.1 MPa to 4.81 MPa, the failure mode changes from brittle shear failure to plastic deformation, the number and width of shear zones significantly increase, and the dilatancy effect enhances. The digital core model constructed based on PFC 6.0 is highly consistent with the physical experimental results, which can not only reproduce the dynamic process from elastic deformation to plastic failure of core samples, but also reveal the mechanism of weakening the interparticle bonding force caused by water infiltration through microscopic damage analysis. As a result, a digital core simulation model for shallow weakly consolidated formations in Bohai Sea area has been established for the first time, quantitatively elucidating the degradation law of increasing water cut on rock mechanical properties. The mechanism of water sensitivity induced disasters has been revealed from the dual scale of “macroscopic mechanical response–microscopic damage evolution”, which provides theoretical support for drilling fluid system optimization, wellbore stability control, and sand control process design, as well as new ideas for mechanical study of weakly consolidated formations in sea area.

In Huanjiang–Hongde–Yanwu area in the western margin of Ordos Basin, oil reservoirs were widely developed in the eighth member of the Mesozoic Yanchang Formation (Chang 8 member), with huge reserve amount, which is a favorable replacement resource for further exploration and increasing reserves in the region. However, the electrical resistivity of Chang 8 member oil reservoir generally ranges in 3–15 Ω·m, and the resistivity ratio between oil layer and water layer is lower than 2, showing low contrast ratio, and leading to great difficulty in oil layer identification. The conventional logging interpretation method has a low accuracy, which is unable to meet the needs of high-efficiency reserve increase and capacity construction. Based on a large amount of well drilling, core data, 3D seismic data, and comparative analysis of logging curves, the genesis of Chang 8 member low-resistivity oil reservoir has been studied from the perspectives of structural evolution and mineralization characteristics. The study results indicate that Chang 8 member low-resistivity oil reservoir in the western margin of Ordos Basin was mainly caused by high salinity of formation water and high saturation of bound water. By using an artificial neural network model and variables of six key logging parameters, two sensitive parameters have been introduced, i.e., Q_Rw and PC₁, and a machine learning model has been established to prepare a cross plot between them, obtaining good distinguishment results among oil layer, oil–water layer, and water layer, with an accuracy of reservoir fluid type recognition improved to 88.9%.