川西北下二叠统茅口组古构造演化与控藏作用  

Evolution of the paleostructure and its control on gas reservoir of Lower Permian Maokou Formation in northwest Sichuan

作　　者：李天军 陈聪 张玺华 于童 杨巍[2] 张萌 张照坤 LI Tianjun;CHEN Cong;ZHANG Xihua;YU Tong;YANG Wei;ZHANG Meng;ZHANG Zhaokun(Research Institute of Exploration and Development,Southwest Oil&Gas Field Company,PetroChina,Chengdu 610500,China;Natural Gas Geology Key Laboratory of Sichuan Province,Southeast Petroleum University,Chengdu 610500,China)

机构地区：[1]中国石油西南油气田公司勘探开发研究院,四川成都610500 [2]西南石油大学天然气地质四川省重点实验室,四川成都610500

出　　处：《断块油气田》2024年第3期467-477,共11页Fault-Block Oil & Gas Field

基　　金：中国石油-西南石油大学创新联合体科技合作项目“深层/超深层碳酸盐岩天然气勘探开发基础理论与关键技术研究”(2020CX010000)。

摘　　要：利用钻井、测井、岩心、野外剖面和地震等资料,开展川西北二叠系茅口组成藏期古构造恢复及控藏作用研究。研究表明:川西北茅口组台缘滩和台内滩发育,寒武系和二叠系烃源岩在区内分布较广;晚二叠世茅口组顶古构造整体呈“南高北低”格局,发育NW—SE向的低幅隆起;早中三叠世该古构造转变为“西高东低”格局,剑阁地区形成了面积较大的古构造圈闭;早侏罗世该古构转变为“东高西低”格局,构造高点向东迁移至九龙山地区,后经喜山期调整为盆地边缘高,中部地区凹陷的格局。流体包裹体均一温度的分析表明,茅口组存在4期油气运移。结合区域生烃演化史,研究认为:晚二叠世茅口组台缘带是原油运移的有利区,早中三叠世形成的剑阁地区古圈闭能够较好地捕获油气,晚三叠世天然气主要向NE方向的剑阁、九龙山和元坝地区形成的低幅度背斜圈闭运移,喜山期天然气进一步向高部位聚集并调整形成现今气藏。剑阁—柘坝场的台缘带与烃源岩和古构造的匹配关系好,具有较大的天然气勘探潜力。Using drilling,logging,core,field profile and seismic data,the paleostructure recovery and reservoir control of Permian Maokou Formation in northwest Sichuan during hydrocarbon accumlation period are studied.The research shows that platform margin shoal and intra-platform shoal are developed in Maokou Formation in northwest Sichuan,and Cambrian and Permian hydrocarbon sources are widely distributed in the area.The paleostructure of the top of Late Permian Maokou Formation is generally characterized by the"high in south and low in north"pattern,and a low uplift in NW-SE direction is developed.During the Early and Middle Triassic,the paleostructure was transformed into the"high in west and low in east"pattern,and a large area of paleostructural trap was formed in Jiange area.In the Early Jurassic,the paleostructural pattern was transformed into the"high in east and low in west"pattern,and the tectonic high point migrated eastward to Jiulongshan area.This paleostructural pattern was adjusted into a pattern of high margin and depression in the middle part of the basin after the Himalayan epoch.Fluid inclusion homogenization temperature analysis shows that there are four stages of oil and gas migration in Maokou Formation.Combining with regional hydrocarbon source evolution history,it is considered that the platform margin zone of Late Permian Maokou Formation is a favorable area for oil and gas migration.Paleo-traps in Jiange area formed in the Early and Middle Triassic can better capture oil and gas.In the Late Triassic,natural gas mainly migrated northeastward to the low-amplitude anticline traps formed in Jiange,Jiulongshan and Yuanba area,and further accumulated towards high parts during the Himalayan period,adjusting and forming the present gas reservoir.The platform margin zone of Jiange-Zhabachang has a good matching relationship with the hydrocarbon source and paleostructure,and has great gas reservoir exploration potential.

关 键 词：气藏 古构造 茅口组 下二叠统 川西北 四川盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探]