Evaluating the Relationship Between Multi‐Parameter Transport Capacity of Oil‐Source Faults and Hydrocarbon Accumulation: A Case Study of the Mesozoic in the Chengdao‐Zhuanghai Area, Bohai Bay Basin

ABSTRACT In fault‐controlled composite hydrocarbon accumulation zones, the transport capacity of oil‐source faults governs hydrocarbon enrichment. This study focuses on the Mesozoic oil‐source faults in the Chengdao‐Zhuanghai area of the Bohai Bay Basin. By integrating data on oil‐source fault characteristics, well logging and hydrocarbon reserve distribution and employing methods such as effective normal fault stress analysis, shale gouge ratio analysis, cross‐plot analysis and analytic hierarchy process, the factors influencing the transport capacity of oil‐source faults were identified. A quantitative evaluation formula for oil‐source fault transport capacity was established and its impact on hydrocarbon accumulation in the Mesozoic strata was analysed. The research shows that among the major controlling faults in the Mesozoic, the Chengbei Fault, Chengbei 30 North Fault, Chengbei 30 South Fault, Zhuanghai 104 South Fault and Chengbei 304 Fault are oil‐source faults, while the Chengbei 20 Fault is a non‐oil‐source fault. The transport capacity of Mesozoic oil‐source faults is primarily determined by three factors: fault activity characteristics during the hydrocarbon accumulation period, fault sealing properties and static fault characteristics. Oil‐source faults with greater extension lengths, higher fault activity rates during the accumulation period and poorer sealing properties exhibit stronger hydrocarbon transport capacity, resulting in larger hydrocarbon distribution areas in the associated Mesozoic blocks. The transport capacity of oil‐source faults correlates with the hydrocarbon reserves in the related Mesozoic blocks, with a correlation coefficient of 88%. The findings of this study provide guidance for further exploration of fault‐block reservoirs in faulted basins.