The Cambrian platform-margin shoals in the Yudu area, Tarim Basin, are important targets for deep and ultra-deep hydrocarbon exploration, but their development and reservoir-forming mechanisms remain poorly constrained. This study integrates 3D seismic interpretation, drilling and logging data, core observations, thin-section petrography, and reservoir characterization to investigate shoal architecture, reservoir characteristics, and controlling processes. Seismic data reveal that multistage, basinward-prograding carbonate buildups developed along fault-controlled platform-margin slope breaks adjacent to the Yudu rift trough. Core and petrographic observations show that the shoals are dominated by granular, microbial, algal, and oolitic dolomites, with intercrystalline, dissolution, vuggy, and fracture-related pore systems. High-quality reservoirs are preferentially developed within thick, vertically stacked shoal complexes and are characterized by strong heterogeneity and locally enhanced porosity and permeability. Early dolomitization favored the preservation of primary pore frameworks, whereas subsequent faulting and multistage dissolution generated and enhanced fracture–vuggy reservoir space. The spatial association between platform-margin shoals and the Yudu rift trough further provided favorable conditions for near-source hydrocarbon accumulation. These results demonstrate that Cambrian reservoir development was governed by coupled tectono-sedimentary and diagenetic processes and highlight fault-controlled platform margins as favorable targets for deep and ultra-deep carbonate exploration.

This study aims to elucidate the developmental characteristics of strike-slip fault-controlled Ordovician fault-karst reservoirs (FKRs) in the Yuman area of the Tarim Basin. By integrating regional tectonic settings with high-resolution 3D seismic data, we implemented a comprehensive 3D seismic interpretation strategy. Concurrently, a statistical evaluation of 22 strike-slip fault segments was conducted based on their kinematic attributes, connectivity, and seismic “string-of-beads” responses. The results indicate that the Yuman area is dominated by an interlaced network of NE-striking (sinistral transpressional) and NS-striking (dextral transpressional) faults. Three distinct reservoir-controlling patterns were identified among the 22 FKRs: Type I deep-penetrating transpressional (7 segments), Type II deep-penetrating transtensional (4 segments), and Type III weakly penetrating transpressional (11 segments). Based on reservoir scales and structural positioning, seven high-priority exploration targets were successfully delineated. Furthermore, the results reveal that fault structural maturity, vertical penetration, and kinematic regimes are the pivotal factors controlling FKR quality and stratigraphic distribution. Type I patterns exhibit the highest structural maturity and develop cross-stratigraphic, large-volume reservoirs in shallow sections, representing prime targets. Conversely, Type III reservoirs are deeply buried due to constrained fault growth. Ultimately, reservoir evaluation priority ranges from Type I, through Type II, to Type III, with Targets ① to ④ identified as the most promising candidates for localized exploration breakthroughs.