Structural evolution and reservoir-control mechanisms of ultra-deep strike–slip fault zones in the Fuman area,Tarim Basin,ChinaOA

The discovery of ultra-deep strike–slip fault–controlled hydrocarbon reservoirs in the central Tarim Basin has renewed interest in the structural evolution and reservoir-controlling mechanisms of intracratonic strike–slip systems.Based on integrated drilling data,high-resolution 3D seismic reflection interpretation,and structural analog modeling,this study investigates the F_(I)12 and F_(I)17 fault zones in the Fuman area as representative examples.The results show that ultra-deep strike–slip faults exhibit combined lateral segmented growth and vertical stratified propagation,with secondary shear faults overlapping and stepping in both horizontal and vertical directions.To characterize fault activity in a reproducible manner,a semi-quantitative slip intensity framework is established using fault-zone width,structural relief,and segmentation complexity.Comparative analysis demonstrates that slip intensity is the first-order control on the scale and effectiveness of fault-controlled carbonate reservoirs:fault zones with higher slip intensity develop wider damage zones,stronger fracture connectivity,and larger reservoir volumes.Within individual fault zones,slip intensity is preferentially concentrated at lateral step-overs and relay zones of secondary shear faults,where large-scale fracture corridors form and hydrocarbon productivity is significantly enhanced.In addition,for reservoirs characterized by a lower-source–upper-reservoir configuration,hydrocarbon productivity is positively correlated with the proximity of vertical fault step-overs to the target reservoir interval.Shallower vertical overlap facilitates more efficient upward hydrocarbon migration,resulting in higher hydrocarbon abundance.These results establish a three-dimensional structural control model linking slip intensity,fault architecture,and reservoir effectiveness in ultra-deep carbonate strike–slip systems,providing a robust geological basis for reservoir prediction and exploration risk reduction in complex ultra-deep settings.