Development characteristics and controlling factors of dolomite reservoirs of permian Qixi a Formation in central Sichuan Basin

In recent years, with the fine exploration of carbonate reservoirs in Qixia Formation, central Sichuan Basin, researchers have made important oil and gas discoveries dolomite reservoirs. However, characteristics, genesis controlling factors Formation this area are still unclear. paper, petrology, pore structures, physical properties geochemical characteristics Permian Basin been systematically studied based on a large number cores, thin sections, property tests. Furthermore, main clarified. The study shows that dolomites small single-layer thickness multi-layer development, they usually interbeded limestones. reservoir types mainly crystal medium dolomite, spaces include intercrystalline pores dissolution (or caves). Moreover, characterized by porosity to high permeability. Quasi-syngenetic dolomitization is origin target layer, was slightly modified hydrothermal solution at end Maokou period. development affected palaeogeomorphology, sedimentation diagenesis. granular shoal facies developed parts paleogeomorphology provides material basis for formation frequency sequence interface controls highstand systems tract. addition, quasi-syngenetic promots early secondary provids an effective channel migration diagenetic fluids later stage. direction orthogonal horizontal deposition, monolayer thickness, multiple sequences interbedded limestone. shoals distributed as clumps plane, which has great potential hydrocarbon exploration.