柴北缘断裂上、下盘油气差异性聚集及成因  

Differential accumulation of oil and gas between hanging and lower walls of fault and its genetic mechanism in the northern edge of Qaidam Basin

作　　者：李宏义[1] 姜振学[1] 庞雄奇[1] 罗群[2] 李玉喜[3] 

机构地区：[1]中国石油大学(北京)盆地与油藏研究中心 [2]中国石油大学(北京)石油天然气成藏机理教育部重点实验室 [3]国土资源部油气资源战略研究中心

出　　处：《石油勘探与开发》2006年第5期586-590,共5页Petroleum Exploration and Development

基　　金：国家"十五"天然气(二期)攻关项目资助(2004BA616A-04)

摘　　要：柴达木盆地南缘昆北地区断裂上盘富集油气,而柴北缘中、浅层油气藏主要赋存于断裂下盘圈闭之中。研究认为,柴北缘滑脱断裂下盘圈闭油气富集的根本原因是:①柴北缘中、浅层滑脱断裂本身不是油源断裂,不能直接向其上盘圈闭提供油气;②柴北缘中、浅层滑脱断裂(带)在垂向上因封闭性不同而具有分带性,即主断裂带封闭性最强,其上、下带封闭能力变差,这是油气沿断裂带下带运移的先决地质条件;③滑脱断裂主断面之下的下带因地质条件的变化,其封闭性由上而下逐渐变好,为滑脱断裂下盘多层油气的聚集提供了遮挡条件。因此,有基底油源断裂沟通的滑脱断裂下盘是柴北缘油气勘探的重要领域,而上盘则存在较大的勘探风险。Oil-gas reservoirs in middle and shallow strata exist in the traps of lower walls of faults in the northern edge of Qaidam Basin, which is opposite to the Kunbei area in the southern edge of the basin. Geological conditions of faults and faulted belts in the middle-shallow strata show that the reasons for the enrichment of oil and gas in the lower walls of detachment faults in the northern edge are as follows： detachment faults in the middle-shallow strata don＇t incise source rocks and cannot provide oil and gas to the hanging wall; faulted belts have zonations because of sealing differences in the direction vertical to fault-plane; the sealing of the zones below the main fault-plane gets better gradually down the slope, providing favorable conditions for the formation of multilayer oil-gas reservoirs in the lower walls of detachment faults. The lower walls of detachment faults connected by faults incising source rocks are important exploration fields in the northern edge of the basin.

关 键 词：柴北缘 滑脱断裂上 下盘 油气差异性聚集 断裂带封闭性 

分 类 号：TE122.3[石油与天然气工程—油气勘探]