东营凹陷古近系层序地层对成岩规律的控制作用

东营凹陷古近系发育了沙四段底界面(T7)、沙四段与沙三段分界面(T’6)及沙二下亚段顶界面(T’2)等3个二级层序界面。根据对储集层成岩作用的深入研究发现,原有的埋藏成岩作用序列不仅受深度的影响,而且受此层序地层所控制,在层序界面附近和层序体内部存在一定的规律性。据此确定了层序界面附近发育的淋滤、溶解成岩相带和层序体内部发育的黏土矿物转换和化学胶结成岩相带。认识到层序界面通常是流体运移的通道,影响界面上下低水位体系域和高水位体系域内储集层的成岩相展布,对改善储集层储集性能有利;层序体内部储集层成岩差异性明显,储集性往往受到制约。

PALEOGENE SEQUENCE STRATIGRAPHY IN THE DONGYING DEPRESSION AND ITS FUNCTIONS OF CONTROLLING DIAGENESIS

There are three interfaces of 2-order sequence in the Paleogene strata of the Dongying Depression, that are,interface under the Member 4 of Shahejie Formation (T7), the boundary between the Member 4 and the Member 3 of Shahejie Formation (T'6) and the top boundary of the lower Member 2 of Shahejie Formation (T'2). According to intensive study of reservoir diagenesis,it was found that the burial diagnesis sequence is not only influenced by depth but also is controlled by sequence strata. There are some special rules near the sequence interfaces and in the interior of sequence. Here by the diagenetic facies belt was determined as leaching and solvation near sequence interface and clay transform, chemistry cementation in the interior of sequence. It was known that the channels of liquid moving is generally sequence interface, which influences the diagenetic facies spreading of reservoir in high water system tract and low water system tract below or above the interface,advantageous to the improvement of the reservoir. The difference of diagenesis is evident in the reservoir interior and the reservoir permeability is always restricted.