龙门山北段推覆构造带-山前带构造解析及油气勘探前景  

Structural analysis and exploration prospects of nappe-piedmont structural belt in northern Longmenshan area,Sichuan Basin

作　　者：谢格云 胡欣 王旭丽 杨涛 田云英 辛荣跃 梅杰 李洪林 XIE Geyun;HU Xin;WANG Xuli;YANG Tao;TIAN Yunying;XIN Rongyue;MEI Jie;LI Honglin(Northwestern Sichuan Gas District,PetroChina Southwest Oil&Gasfield Company,Jiangyou,Sichuan 621709,China)

机构地区：[1]中国石油西南油气田公司川西北气矿,四川省江油市621709

出　　处：《天然气勘探与开发》2023年第1期11-18,共8页Natural Gas Exploration and Development

基　　金：中国石油西南油气田公司科研项目“四川盆地二叠系规模增储关键问题攻关研究——川西地区下二叠统气藏特征及成藏条件深化研究”(项目编号:20220301-03-05)。

摘　　要：2014年,四川盆地双鱼石构造中二叠统栖霞组钻获高产工业气流以来,随着勘探开发工作的持续开展,已钻获多口高产工业气井,深入开展龙门山推覆构造带—山前带构造特征研究,是认识该区上古生界气藏特征、进一步向推覆构造带拓展油气勘探领域的重要前提。为此,基于新完钻的红星1井实钻成果、新解释的束线三维地震资料,解剖了龙门山逆冲推覆构造带—山前带的构造特征,进而分析了山前隐伏构造带的天然气成藏条件和勘探前景。结果表明:①龙门山推覆构造带发育一系列向盆内逆冲断裂,形成多套推覆体叠置,表现为多个断层传播褶皱叠加,推覆断裂下盘隐伏构造带,表现为挤压断褶构造;②二叠系推覆体及原地地层油气显示丰富,含气性好,隐伏构造带栖霞组发育台缘滩相白云岩,白云岩储层储集性能好;③隐伏构造带面积大,天然气成藏条件好,具有良好的勘探前景,是川西北部地区深层海相层系勘探拓展寻找规模新突破的重要有利区带。In 2014,commercial gas flow was obtained from the Middle Permian Qixia Formation of Shuangyushi structure in the Sichuan Basin.Several high-yield gas wells have been drilled through continuous exploration and development.The study on properties of the Longmenshan nappe-piedmont structural belt is valued as an essential prerequisite for understanding the characteristics of the Upper Paleozoic gas reservoirs in this area,and further extending the exploration to nappe belts.Therefore,based on the drilled Well Hongxing 1 and newly interpreted beamline 3D seismic data,the structural characteristics of the Longmenshan thrust nappe–piedmont belt were identified so as to analyze the gas accumulation and exploration prospects of the piedmont buried structural belt.The results show that,(1)a series of basinward thrust faults are developed in the nappe structural belt,forming superimposed multiple nappes which appear as multiple fault-propagation folds,and footwall buried structural belt of thrust fault which presents as a compressional fault-fold structure;(2)the Permian nappes and in-situ formations indicate good gas-bearing property with rich oil and gas shows;there develops marginal-platform shoal dolomites in the Qixia Formation of buried structural belt,which exhibit good reservoir performance;and(3)the buried structural belt,with large area and favorable conditions of gas accumulation,suggests promising exploration prospects,indicating a critical target for new exploration breakthroughs of deep marine strata in northwestern Sichuan Basin.

关 键 词：龙门山推覆构造带 隐伏构造带 构造特征 储层特征 天然气成藏条件 勘探前景 

分 类 号：P618.13[天文地球—矿床学]