塔里木盆地库车坳陷膏盐质盖层特征与天然气保存

ROCK MECHANIC CHARACTERISTICS OF GYPSUM COVER AND CONSERVATION FUNCTION TO GAS IN THE KUCHE DEPRESSION, THE TARIM BASIN

付晓飞 宋岩 吕延防 孙永河

Fu Xiaofei Song Yan Lü Yangfang Sun Yonghe

中国石油天然气股份有限公司, 勘探开发研究院, 实验中心, 北京, 100083 2. 大庆石油学院, 地球科学学院, 黑龙江, 大庆, 163318

Research Institute of Petroleum Exploration and Development, CNPC, Beijing 100083, China 2. School of Earth Sciences, Daqing Petroleum College, Daqing, Heilongjiang 163318, China

根据模拟实验结果分析了塔里木盆地库车坳陷北部第三系膏盐质盖层岩石力学特征。膏岩、盐岩和泥岩为塑性材料,变形过程为典型的塑性形变,蠕变表明第三系膏盐质盖层具有较强的流动性。构造挤压使膏盐质盖层塑性流动,受断裂改造作用往往在构造圈闭上方形成巨厚的膏泥岩层。膏泥岩岩性致密,排替压力高,普遍具有异常高的孔隙流体压力,是一套优质盖层。盖层段内的穿盐断裂和盐内滑脱断裂多为膏泥岩蠕变形成的塑性断层,断裂带内部结构主要为软泥充填的大裂缝组合,伴生裂缝不发育,断裂静止期封闭性好,有效阻止天然气散失。

Rock mechanic characteristics of the Tertiary gypsum cover in the north of Kuche depression is analyzed based on simulation experiment.Plaster rock,salt rock and mudstone are plastic material and have the ability of plastic deformation.Creeping shows that the Tertiary gypsum cover has strong fluidity.Plastic flow appears if the gypsum cover suffers tectonic stress.Under the influence of fault,the gypsum cover usually forms huge gypsum-mud cover tectonic trap,which is compact with high expulsion and pore fluid pressure so as to be good cover.Most of fractures and detachment fractures are formed by gypsum-mud rock creeping.And there are huge fracture groups filled with ooze in fracture zone,which have excellent enclosing function and hold gas back effectively.

国家重大基础研究(973)项目(2001CB20914)

https://doi.org/10.11781/sysydz200601025