China Petroleum Exploration ›› 2026, Vol. 31 ›› Issue (1): 160-179.DOI: 10.3969/j.issn.1672-7703.2026.01.012

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Dynamic Modeling of Ordovician Petroleum Accumulation and Exploration Prospectivity, South-Central Tarim Basin

Ran Junshuai1,3,Li Bing1,3,Yang Suju4,Sha Xuguang4,Xu Qinqi4   

  1. 1 School of Geosicence and Technology,Southwest Petroleum University;2 State Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering,Southwest Petroleum University;3 PetroChina Tarim Oilfield Company;4 Research Institute of Exploration and Development,Northwest Oilfield Company,Sinopec
  • Online:2026-01-15 Published:2026-01-15

Abstract: To address the challenges of low overall exploration levels and complex hydrocarbon accumulation conditions in the Ordovician carbonate rocks of the central and southern Tarim Basin, which hinders the evaluation of hydrocarbon-bearing zones, a hydrocarbon system with the Lower Cambrian as the source rock was constructed using a hydrocarbon accumulation dynamics method. A dynamic simulation of Ordovician hydrocarbon accumulation was conducted using a mixed-flow algorithm, reconstructing the differential evolution history of “generation, migration, and accumulation” in 12 hydrocarbon-bearing zones. The source rocks of the Lower Cambrian Yuertus Formation underwent an early process of mature oil generation and a late process of high-to-over-mature dry gas generation, mainly exhibiting three phases of oil and gas inflow: the Late Caledonian, Hercynian, and Himalayan periods. Deep hydrocarbons in the central-southern Tarim have been maintained in a dynamic balance between migration/accumulation and leakage, giving rise to five charge–dissipation modes. Three dominant enrichment patterns are: deep-sag sourcing with fault-focused delivery and uplift-centered accumulation, yielding an east-gas/west-oil partitioning; fault-controlled charging with layer-controlled trapping, characterized by gas-prone anticline cores and oil-rich flanks; and “lower-source/upper-reservoir” charging with fault-assisted trapping, producing deep gas and shallow oil. An integrated assessment delineates three favorable Ordovician exploration belts: the Yuzhong-low convex Yubei fault zone-Mazatag fault zone and its surroundings (8500km2); the northern segment of the Qibei–Guman structural belt in the Yecheng Depression (5000km2); and the overlap zone between NW-trending thrusts and NE-trending strike-slip faults on the western Katake Uplift (2900km2). The estimated total accumulations are 2366×104t of oil and 14331×104t of gas.

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