Lacustrine Basin Slope Break — A New Domain of Strata and Lithological Trap Exploration

对准噶尔盆地西北缘地区侏罗系、东营凹陷下第三系、松辽盆地南部西斜坡等目的层系层序地层学的研究,认为断陷及坳陷盆地发育多级坡折带,按成因机制可分为构造坡折带、沉积坡折带和侵蚀坡折带。构造运动是坡折带发育的主控因素,而且其规模与构造运动大小息息相关。研究结果认为多级坡折带对非构造圈闭的控制主要表现为:1)非构造圈闭紧邻多级坡折带发育,沿着坡折带呈串珠状展布;2)非构造圈闭在纵向上发具有继承性的特点;3)非构造圈闭发育的类型随着坡折带和坡折带所处的地理位置的不同而不同;4)同一个坡折带在横向上存在较大的变化,可形成不同类型的非构造圈闭;5)多级坡折带的存在导致了在盆地的不同地理位置发生不同的沉积剥蚀响应,非构造圈闭的生、储、盖组合较好;6)坡折带控制下的非构造圈闭的含油性条件十分有利。

Lacustrine Basin Slope Break - A New Domain of Strata and Lithological Trap Exploration

Based on the studies of the Songliao Basin characterized by Cretaceous down-warping, of the Jurassic compressional flexural Junggar basin and of the Bohai Bay Basin characterized by Paleogene rifting, the multiple-grades slope break has developed in lacustrine basins of different origins. Their genetic types can be divided into tectonic slope break, depositional slope break and erodent slope break. The dominant agent of the slope break is tectogenesis, and the scale of slope breaks relates with the size of tectogenesis. The results of the study show that control of mutual grades slope breaks on atectonic traps mainly represent: 1) Atectonic traps develop close to mutual grades slope breaks, with beads-shaped distribution along the slope breaks. 2) In the longitudinal direction, the development of atectonic traps is characterized by the inheritance. 3) Different slope breaks and their different geographical positions can lead to different development types of atectonic traps. 4) A slope break can form different kinds of atectonic traps because of its great lateral variation. 5) The existence of mutual-grade slope breaks leads to different responses of erosion and deposition at different geographical positions in the basin. The oil source bed, reservoir and cap rock combination of atectonic traps is fine. 6) The oil-bearing condition of atectonic traps controlled by slope breaks is very favorable.