辽河盆地西部凹陷曙二区大凌河油层湖底扇沉积特征与沉积模式探讨

利用成熟探区翔实的岩芯、录井和测井等资料，研究了辽河盆地西部凹陷曙二区大凌河油层湖底扇沉积特征与沉积模式。研究表明，大凌河油层湖底扇具有较为发育的水道体系（主沟道或辫状沟道），平面上相带展布、扇体的分布面积、砂体延伸方向和分布模式受水道及古地貌变化的控制。水道体系及其控制的沉积体呈顺源、带状展布。主沟道向前延伸逐渐变为规模较大的辫状沟道沉积，两侧发育辫状沟道侧缘，呈条带-舌形展布，向湖方向逐渐演变为多支小型末端辫状沟道沉积。湖底扇内部平面微相序列表现为“主沟道→主沟道堤→深湖泥”或“辫状沟道→辫状沟道侧缘→辫状沟道间（或末梢）→深湖泥”的变化特征。每支辫状沟道控制形成的带状沉积体间均为明显深湖-半深湖泥岩沉积分割，呈带状-舌状沉积体向湖盆中心延伸较远。

Sedimentary Characteristics and Model of Sublacustrine Fan of Dalinghe Oil Layer of Shu2 Area in the West Sag,Liaohe Basin

Based on cores data, geological logging data and logging data in mature exploration area, sedimentary characteristics and models of Dalinghe oil layer in Shu2 area of the West Sag has been analyzed. It shows that the gravity flow channels are widely developed in the sublacustrine fan of Dalinghe oil layer. The plane distribution, sandbody extended direction and distribution pattern of sublacustrine fan is controlled by gravity flow channels and ancient landform. The gravity flow channels and its controls on sedimentary body are banding distribution along the source direction. The main channel is gradually extended to relatively larger scale braided channel. The sides of the braided channel are the edges of the braided channel, which are banding distribution or tongue distribution. The braided channel is gradually becoming multi branched and small braided channel endings to the direction of the lake. Microfacies sequence of sublacustrine fan is the main channel→the embankment of main channel→deep lacustrine mudstone or the braided channel→the edges of the braided channel→endings microfacies→deep lacustrine mudstone. Each banded sedimentary body controlled by the braided channel is separated by deep lacustrine mudstone. And it is banding distribution or tongue distribution extending to the center of the basin far away.