川西南缘天宫堂构造奥陶系五峰组—志留系龙马溪组页岩气富集主控因素

综合利用地震、钻井、测井及岩心分析化验资料,分析了四川盆地西南缘天宫堂构造奥陶系五峰组—志留系龙马溪组的构造、沉积、储层及可改造性等基本地质特征,探讨了页岩气富集主控因素及成藏模式.研究结果表明:①天宫堂构造优质页岩集中分布在五峰组—龙马溪组龙一1亚段,Ⅰ类储层主要发育于龙一11—龙一13小层,厚度为0.8～17.0 ...

Main controlling factors of Ordovician Wufeng-Silurian Longmaxi shale gas enrichment in Tiangongtang structure,southwestern margin of Sichuan Basin

The data of seismic,drilling,logging and core analysis and test were comprehensively used to study the structure,deposition and basic reservoir geological characteristics of Ordovician Wufeng-Silurian Longmaxi Formation in Tiangongtang structure in southwestern margin of Sichuan Basin,and the main controlling factors of shale gas enrichment and accumulation model were discussed.The results show that:(1)The high-quality shale in Tiangongtang structure is mainly developed in O₃w-S₁l_1-1.TypeⅠreservoir is mainly developed in S₁l_1-1-1-S₁l_1-1-3 layers,with a thickness of 0.8-17.0 m,and characterized by high TOC content,good gas-bearing property and highly brittle minerals.(2)Tiangongtang structure has experienced rapid subsidence,deep burial and a large amount of hydrocarbon expulsion before the Late Cretaceous,forming an early enriched overpressure shale gas reservoir.After the Late Cretaceous,it was uplifted and reformed in two phases,and the early enriched overpressure shale gas reservoir gradually transformed to high pressure-normal pressure shale gas reservoir.(3)The preservation conditions of Tiangongtang structure are affected by stratigraphic dip angle and Gong-1 fault,resulting in differential enrichment of shale gas in different structural zones.(4)Tiangongtang structure is an anticline structure-type accumulation model of“early deep burial promotes enrichment,later uplift adjusts enrichment,and preservation conditions control enrichment”.The southwest tip of the structure is a potential favorable area for next shale gas exploration and development.