川西坳陷中段沙溪庙组天然气成藏条件分析

探讨川西坳陷中段沙溪庙组天然气成藏地质条件,为油气勘探提供理论依据。从油气的烃源条件、储集条件、保存条件及成藏组合方面入手,结合构造史以及岩心、地震及钻井等资料进行分析,结果表明川西坳陷中段处于生烃坳陷中心地带,烃源岩丰富,具备生烃能力。晚三叠世中、晚期发育冲积扇—河流沉积相带,储集条件良好,后期构造运动使断层裂缝系统较发育,有利于储集条件改善和油气富集。其上有压力封存箱和巨厚的砂泥岩互层,保存条件良好。川西坳陷中段新场—盐亭地区近EW向古隆起及龙门山前缘扩展变形带中的鸭子河—石板滩地区是油气勘探的有利地带。

Natural gas reservoir-formation condition of Shaximiao Formation in mid-band of Western Sichuan Depression

Natural gas reservoir-formation condition of Shaximiao Formation in mid-band of Western Sichuan Depression was discussed in order to provide evidence to explore oil and gas.Source rocks,reservoir,preservation,and play were analyzed combining with structure history,rock core data,seismic data and drill data,the result indicated that the mid-band of Western Sichuan Depression was located in the center of hydrocarbon producing zone and source rocks developed widely here.In the mid-late of late-Triassic,alluvial fan and fluvial deposition developed and fault breaks developed in the late of late-Triassic which was good for gas accumulation.Preservation is good because pressing boxes and thick sand shale imbedded upon reservoirs.Palaeohigh of EW direction in Xinchang-Yanting area in mid-band of Western Sichuan Depression and Yazi River-Shibantan area in spread deformable zone in front of Longmen Mountain are good belts for oil and natural gas exploration.