Strike–Slip Fault and Reservoir Quality Control on Hydrocarbon Accumulation in Tight Sandstone in Lower Kepingtage Formation, Shuntuoguole Low Uplift, Tarim Basin

Exploration of ultra-deep tight sandstones in the Silurian Lower Kepingtage Formation, Tarim Basin, is hindered by low success rates. Here, we integrated 3D seismic, core, and petrographic data to investigate reservoir characteristics and fault controls on hydrocarbon accumulation. The formation was characterized by low porosity (3–9%) and permeability (0.01–1.1 mD), with residual intergranular and dissolution pores as primary storage. Strike–slip faults exhibited distinct Riedel shear segmentation—extensional, translational, and compressional—resulting in variable vertical connectivity. Comparative analysis of Wells W3 and W5 revealed that reservoir physical properties, rather than structural location or fault proximity, dominate accumulation outcomes. Specifically, Well W5 achieved high production on a slope due to superior reservoir quality, whereas structurally high Well W3 failed due to poor physical properties. We propose a paradigm shift from targeting “structural highs” to identifying “high-quality sandy bodies” at the intersection of fault conduits and favorable lithologies. This study provides a robust theoretical basis for ultra-deep tight oil and gas exploration.