Paleo-Fluid Migration and Conservation Conditions of Shale Gas in Jiaoshiba-Wulong Area

The development of the differential tectonic zones in the Jiaoshiba-Wulong area with complex paleo-fluid activities is crucial to the preservation of shale gas. The fracture veins of two typical anticlines (steep anticlines and box anticlines) are studied. Based on the theory of fractal fracture and carbon, oxygen and strontium isotope geochemistry, it reveals the differences of paleo-fluid activities in different structure and coupling of shale gas preservation conditions. The study suggests fellows:(1) There is coupling between tectonic deformation and paleo-fluid activity. The fluid is more active in the tectonic stress concentration areas (such as box anticlinal hinge, hidden faults) than other parts of the structure. (2) There is coupling between paleo-fluid tracer differences and shale gas preservation conditions. Isotope geochemistry reveals that the internal fluid flow dominates in the Permian-Lower Triassic formation, and the sealing ability is good. The Wufeng-Longmaxi shale gas of the high-steep anticline in the basin and the residual syncline outside the basin has certain exploration prospects. There exists the trace of cross-layer fluid activities in the Middle Cambrian-Lower Ordovician formation, and the sealing ability deteriorates. The risks of shale gas exploration in the Lower Cambrian Qiongzhusi Formation of the box anticline outside the basin increased.