The X-type strike-slip fault system and weathering crust karst fracture-cave and channel reservoirs were developed in the Halahatang area of the northern Tarim Basin. However, the relationship between the reservoir and the strike-slip fault remains controversial. Based on the core data, and taking an NE-striking strike-slip fault as an example, this paper dissects the karst reservoir from wells along the strike-slip fault damage zone and analyzes the control of scales, properties, and segmentation styles of strike-slip faults on karst reservoirs. The results show that (1) the scale of the strike-slip fault controls the distribution of the reservoir—the wider the fault damage zone, the wider the fracture-cave reservoirs; (2) the transtensional segments of the strike-slip fault are more likely to produce karstification, and the buried-hill area and the interbedded area are controlled by different hydrodynamic conditions to form different types of karst reservoirs; (3) six different parts of the strike-slip fault are conducive to the formation scale of fault fracture zones. This research provides new insight into recognizing karst reservoirs within strike-slip fault damage zones, which can be further applied to predict karst reservoirs controlled by strike-slip faults.

Deeply buried Ordovician carbonate reservoirs in the Tarim Basin face significant exploration risks due to extreme heterogeneity. Focusing on the Lungu area, this study integrates high-resolution 3D seismic, well-log, and core data to unravel the multiscale genesis of epikarst fracture-vug reservoirs. We reconstruct the pre-Carboniferous paleogeomorphology and delineate karst water systems to quantify their control on reservoir development. Results indicate that the Yingshan Formation is dominated by sparry grainstones, with reservoir space governed by secondary dissolution. Seven secondary geomorphic units were identified, revealing a stepwise decrease in epikarst zone thickness from ∼45 m (highlands) to ∼10 m (basins). Crucially, we identify seven secondary karst water systems, demonstrating that their boundaries (watersheds, faults, dense fillings) act as primary controls on reservoir. A “Tectonics-Paleogeomorphology-Hydrodynamics” ternary model is established: highlands favor fracture-type reservoirs via rapid vertical percolation, while gentle slopes develop superior fracture-vuggy reservoirs through diffuse flow and prolonged water-rock interaction. The coupling of NEE-trending master faults and surface drainages creates optimal “sweet spots” with large cave systems. This research shifts the paradigm from static geomorphic mapping to dynamic water-system-constrained evaluation, providing a robust framework for predicting fracture-vug units in deep karst plays.