川西坳陷中段陆相地层压力演化及其成藏意义  

Evolution of continental formation pressure in the middle part of the Western Sichuan Depression and its significance for hydrocarbon accumulation

作　　者：郭迎春[1,2] 庞雄奇[1,2] 陈冬霞[1,2] 冷济高[3] 田军[3] 

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室 [2]中国石油大学(北京)地球科学学院盆地与油藏中心 [3]中国石化西南油气分公司勘探开发研究院

出　　处：《石油勘探与开发》2012年第4期426-433,共8页Petroleum Exploration and Development

基　　金：国家重点基础研究发展规划(973)项目(2011CB201102);国家自然科学基金项目(41072100)

摘　　要：以川西坳陷中段现今地层压力分布、测井资料分析及超压成因机制探讨为基础,利用盆地模拟技术及其他定量分析方法恢复该地区的地层压力演化史,讨论增压机制的阶段差异性、不同机制增压幅度的差异性以及压力演化对天然气运移聚集成藏的控制作用。研究表明,川西坳陷中段须家河组超压的主要成因机制有欠压实作用(晚三叠世早期—侏罗纪末)、生烃作用(早侏罗世末—新近纪)和构造挤压作用(白垩纪至今),构造挤压和生烃作用是现今须家河组超压的主要成因。侏罗系超压的主要成因是超压传递作用,主要发生在白垩纪以来构造活动强烈时期。超压是天然气运移的主要动力,超压产生的裂缝是天然气运移的主要通道,断裂输导和超压驱动促使了侏罗系"远源次生气藏"的形成。侏罗系压力系数高值区和须家河组中高超压带是该区今后勘探优选目标。Based on the distribution features of present formation pressure, analysis on logging data, and genetic mechanisms of abnormal pressure, the overpressure evolution was reconstructed using numerical basin simulation and other quantitative analysis methods. The phase differences of pressure increasing mechanisms, enhancement differences among different mechanisms, and the control of geopressure evolution on gas migration and accumulation were discussed. The causes of overpressure in the Xujiahe Formation include under-compaction （from early Late Triassic to the end of the Jurassic）, hydrocarbon generation （from end of the Early Jurassic to the Neogene） and tectonic compression （since the Cretaceous）. It is suggested that tectonic compression and hydrocarbon generation are the principal factors of the present overpressure in the Xujiahe Formation. Overpressure transmission is the main cause of overpressure in the Jurassic strata which occurred during the intense tectonic activity periods since the Cretaceous. The overpressure is the main force for hydrocarbon migration and overpressure-related microfractures are the major pathways for gas migration. Fault transport and overpressure driving caused the formation of Jurassic secondary gas reservoirs with distant sources. The areas with high pressure coefficient in the Jurassic and high-overpressure zones in the Xujiahe Formation are optimum targets for exploration.

关 键 词：异常压力 欠压实 生烃增压 构造挤压 超压传递 成藏 川西坳陷 

分 类 号：TE122.1[石油与天然气工程—油气勘探]