Segmentation characteristics of the strike-slip fault and their controls on the hydrocarbon accumulation and enrichment in the northern Tarim Basin, NW China

The first ultra-deep (>6000 m) X-type conjugate strike-slip fault-controlled oilfield (Halahatang Oilfield) was found in Ordovician carbonates in the northern Tarim Basin. However, the effects of fault segmentation on hydrocarbon accumulation and enrichment are illusive, leading to complicated fluid and oil production along the fault zone. Based on newly reprocessed high-precision 3D seismic data and production data from wells along the NE-SW-striking F(I)7 strike-slip fault zone in the Halahatang Oilfield, this paper investigates the characteristics of fault segmentation and liquid change, and further discusses the influences of fault segmentation on hydrocarbon accumulation and distribution. The strike-slip fault shows distinct segmentation with isolated to linear fault segments and differential deformation that are related to the low maturity of the fault zone. The oil-gas migration-related geochemical data and production data indicate the segment architecture of the strike-slip fault controlled the differential hydrocarbon migration and enrichment. Four types of oil-gas enrichment models in different karst zones are presented to show the coupling of large-scale fault damage zone, karstic fracture-cave reservoir and localised structural height. The low-mature fault zone has led to the preservation of the intact conjugate strike-slip fault system and subsequent segmentation of the fault zone, fractured reservoir, fluid and oil enrichment. This study provides a potential direction for petroleum exploration and exploitation in the complex karst zones of deep carbonate reservoirs.