龙门山山前复杂构造带双鱼石构造栖霞组超深层整装大气田的形成  

Formation of ultra-deep integrated giant gas field in Qixia Formation of Shuangyushi structure in the foothill complex structural belt of Longmen Mountain

作　　者：杨雨[1] 姜鹏飞[1] 张本健[2] 肖笛[3] 汪华[2] 雷程[2] 张亚[2] 陈骁[2] 刘冉[2] 李亚[2] YANG Yu;JIANG Pengfei;ZHANG Benjian;XIAO Di;WANG Hua;LEI Cheng;ZHANG Ya;CHEN Xiao;LIU Ran;LI Ya(PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610051,China;Exploration and Development Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610041,China;The Key Laboratory of Natural Gas,Southwest Petroleum University,Chengdu,Sichuan 610500,China)

机构地区：[1]中国石油西南油气田公司 [2]中国石油西南油气田公司勘探开发研究院 [3]西南石油大学天然气重点实验室

出　　处：《天然气工业》2022年第3期1-11,共11页Natural Gas Industry

摘　　要：以往在四川盆地西北部龙门山山前复杂构造带以冲断推覆带的勘探为主且主要集中在中深层,近期该区中二叠统天然气勘探取得重大突破,发现了双鱼石构造栖霞组超深层整装大气田,并且揭示出一个油气规模成藏的勘探新领域——冲断掩伏带与前缘背冲带原地构造超深层。为了给下一步油气勘探部署提供依据和参考,基于对生储盖组合以及圈闭等油气成藏要素的分析,总结了双鱼石构造栖霞组气藏的形成机制与模式。研究结果表明:(1)该区栖霞组储层受台地边缘滩微相的控制,叠合早成岩期岩溶与白云石化作用改造,形成以溶蚀晶间孔为主要储集空间的孔隙型储层;(2)栖霞组气藏天然气的来源包括下寒武统筇竹寺组泥页岩和中二叠统栖霞组、茅口组泥灰岩,该区规模发育下寒武统与中二叠统优质烃源岩,为气藏形成提供了充足的气源;(3)栖霞组储层与寒武系、二叠系烃源岩组成“下生上储”和“自生自储”的近源高效源储组合,烃源断层有效沟通源岩和储层,其上发育茅口组泥灰岩直接盖层和三叠系膏岩区域盖层,生、储、盖组合良好;(4)受龙门山推覆构造挤压作用以及双滑脱层夹持的影响,双鱼石构造栖霞组以层内原地背冲背斜构造为特征,与晶粒白云岩共同作用并形成了构造—岩性复合圈闭,不同构造高带上的钻井属于同一个压力系统,展现出整装气藏的特征,含气面积合计达到1900 km2。结论认为,较之于冲断推覆带,原地构造超深层构造变形弱,断层在沟通下部烃源岩的同时又未破坏圈闭的封盖性,油气早期成藏后得以稳定保存至今,这是双鱼石构造栖霞组天然气能够规模成藏的关键。Previous exploration in the foothill complex structure belt of Longmen Mountain in the northwestern Sichuan Basin focuses on the thrust nappe belt in the mid-deep strata.And recently,great breakthroughs have been made in the exploration of Middle Permian natural gas in the area,and an ultra-deep integrated giant gas field has been discovered in the Qixia Formation of Shuangyushi structure,which reveals a new exploration area of large-scale hydrocarbon accumulation,i.e.,the ultra-deep autochthonous structure thrust buried belt and front back-thrust.In order to provide the basis and reference for the next oil and gas exploration and deployment,this paper summarizes the formation mechanisms and models of the gas reservoir in Qixia Formation of Shuangyushi structure based on the analysis of hydrocarbon accumulation factors such as source-reservoir-cap assemblages and traps.And the following research results are obtained.First,the Qixia Formation reservoir in this area is controlled by platform edge beach microfacies,which is reworked into a pore-cavity reservoir with dissolved intercrystalline pores and cavity as the main reservoir space by superimposed karst and dolomitization in the early diagenesis stage.Second,the source of natural gas in Qixia Formation gas reservoir includes the shale of Lower Cambrian Qiongzhusi Formation and the marl of Middle Permian Qixia Formation and Maokou Formation.High-quality source rocks of Lower Cambrian and Middle Permian are developed extensively in this area,providing sufficient gas source for the formation of gas reservoirs.Third,the Qixia Formation reservoir and the Cambrian and Permian source rocks constitute the near-source and high-efficiency source-reservoir assemblages of"lower source and upper reservoir"and"self-source and self-reservoir"with source faults communicating source rocks and reservoir effectively,and the direct marl caprock of Maokou Formation and the regional gypsum caprock of Triassic are developed above it so that good source-reservoir-cap assemblages are f

关 键 词：四川盆地西北部 龙门山山前带 中二叠统栖霞组 超深层整装大气田 原地构造 生储盖组合 气藏形成 

分 类 号：P618.13[天文地球—矿床学]