蜀南地区中二叠统茅口组油气成藏演化与气藏分布规律  

Evolution of oil and gas formation and distribution of gas reservoirs in the Middle Permian Maokou Formation of Shunan area

作　　者：高兆龙 李跃杰 张玺华[1] 袁海锋[2] 彭瀚霖[1] 郝毅 曹华[1] 姚倩颖 朱可丹 GAO Zhaolong;LI Yuejie;ZHANG Xihua;YUAN Haifeng;PENG Hanlin;HAO Yi;CAO Hua;YAO Qianying;ZHU Kedan(PetroChina Southwest Oil and Gasfield Company,Chengdu 610051,China;State Key Laboratory of Oil and Gas Reservoir Geology and Erploitation,Chengdu University of Technology,Chengdu610059,China;PetroChina Hangzhou Geological Research Institute,Hangzhou 310023,China)

机构地区：[1]中国石油天然气股份有限公司西南油气田分公司,四川成都610051 [2]成都理工大学“油气藏地质及开发工程国家重点实验室”,四川成都610059 [3]中国石油杭州地质研究院,浙江杭州310023

出　　处：《天然气地球科学》2025年第2期307-321,共15页Natural Gas Geoscience

基　　金：中国石油天然气股份有限公司重大科技专项(编号:2023ZZ16YJ01)资助。

摘　　要：蜀南地区中二叠统茅口组是目前四川盆地增储上产的主力层系之一,但由于该地区储层类型多样,天然气分布规律复杂,成藏演化特征仍然不明。通过天然气组分与碳同位素特征明确天然气来源,根据流体包裹体特征,结合典型构造与单井埋藏史—热演化史,确定油气充注期次与时间;应用钻井资料及地震资料,恢复油气成藏关键时期茅口组顶面构造形态,从圈闭形成演化与油气充注间的耦合关系剖析研究区油气成藏演化。结果表明:①蜀南地区茅口组天然气主要成分CH_(4)含量均大于95%,H_(2)S含量较低,是典型的干气,为高—过成熟阶段的原油裂解气;主要来源于下志留统龙马溪组烃源岩,同时存在中二叠统茅一段烃源岩混合。②蜀南地区茅口组存在5期烃类充注:第Ⅰ期晚三叠世—早侏罗世古油藏初始形成阶段;第Ⅱ期中侏罗世—晚侏罗世古油藏大量充注阶段;第Ⅲ期晚侏罗世—早白垩世古油气藏形成阶段;第Ⅳ期早白垩世—中白垩世晚期古气藏形成阶段;第Ⅴ期晚白垩世至今古气藏调整与定型阶段。③印支晚期—燕山早期,受泸州古隆起发育控制,位于古隆起核部或翼部构造高点形成早期古油藏聚集,具“印支期古油藏高位聚集”特征;燕山早—中期,随着持续深埋,古隆起继承性发育,得胜、牟家场等构造高部位古油藏持续充注,同时原油开始逐渐裂解,此时为古油气藏演化阶段。到燕山晚期,泸州古隆起逐渐解体,持续深埋,古油气藏转化为古气藏,具“燕山期古油藏裂解成气”特征;喜马拉雅期至今,泸州古隆起完全解体,受喜马拉雅期构造运动与古隆起控制,古气藏发生调整与定型,形成现今气藏,具“喜马拉雅期弱调整富集成藏”特征。The Middle Permian Maokou Formation in Shunan area is one of the main reservoirs in Sichuan Basin,but due to the variety of the reservoir types in the area,the natural gas has a complicated distribution pattern,and the characteristics of the reservoir formation and evolution are still unknown.This study clarifies the source of natural gas through the analysis of natural gas components and carbon isotope characteristics.It also determines the timing of oil and gas charging by examining fluid inclusion characteristics,along with typical tectonic features and single-well burial history-thermal evolution history.By integrating drilling and seismic data,the study reconstructs the tectonic morphology of the Maokou Group during the key period of oil and gas formation,and analyzes the oil and gas formation evolution in the study area in terms of the coupling between the formation evolution of the ring closure and the oil and gas injection.The results show that:(1)The natural gas of Maokou Formation in Shunan area has a CH_(4),content greater than 95%,with low H_(2)S content,which is a typical dry gas,and is the cracking gas of crude oil in the high-over-matured stage;it is mainly originated from the hydrocarbon source rocks of Longmaxi Formation of the Lower Silurian,with a mixture from the hydrocarbon source rocks of the Maoyuan section of the Middle Permian at the same time.(2)There are five stages of hydrocarbon accumulation in Shunan Maokou Formation,i.e.,the initial formation stage of Late Triassic-Early Jurassic paleo-oil reservoirs;the massive filling stage of Middle Jurassic-Late Jurassic paleo-oil reservoirs;the formation stage of Late Jurassic-Early Cretaceous paleo-oil reservoirs in the third stage;the formation stage of Early Cretaceous-Middle Cretaceous paleo-gas reservoirs in the fourth stage;the stage of Late Cretaceous paleo-gas reservoirs adjusting and stabilizing stage since the fifth stage.(3)During the Late Indo-Cretaceous-Early Yanshan period,the development of Luzhou ancient uplift played a crucial

关 键 词：蜀南地区 茅口组 油气成藏演化 成藏模式 气藏分布 

分 类 号：TE122.1[石油与天然气工程—油气勘探]