东濮凹陷沙三段盐岩形成机理浅析

东濮凹陷为典型的与盐岩有关的含油气凹陷,沙河街组三段发育有巨厚的盐层,为封闭的陆相湖盆环境沉积,其分布受凹陷基底深大断裂控制。湖盆深部热卤水为沙三段盐岩主要提供物质来源,贯穿凹陷基底的深大断裂主要为热卤水运移通道,强烈蒸发作用及卤水分层作用使盐类矿物及高盐度卤水沿湖底深凹处富集而形成巨型厚的沙三段盐层。

THE GENESIS OF HALITE IN 3rd MEMBER OF SHAHEJIE FORMATION OF DONGPU DEPRESSION

Dongpu depression is a typical petroliferous depression which is related to halite.There is huge thick halite in the 3rd Member of the Shahejie Formation that belongs to terrestrial obturated lacustrine facies.The halite's distribution is dominated by deep and huge faults in the depression.The hot brine in the lacustrine's deep strata is the major material supply to the halite of the 3rd Member of Shahejie Formation;Meanwhile,deep and huge faults involved in the depression's basement rock are the main migration routeways of the hot brine.Thus,saline minerals and high salinity brine are rich in the deep areas of the lacustrine and give rise to tremendous thick halite layers in the 3rd Member of Shahejie Formation,due to the functions of serious evaporation and the brine deliaination.