蠡县斜坡中北部沙二段—沙一段层序地层研究

通过对研究区岩芯、地震、测井和录井等资料的综合研究，建立了沙二段—沙一段的层序地层格架，将其归为2个三级层序，划分出低位体系域、湖扩展体系域和高位体系域3种类型的6个体系域，并在此基础上进行了详细的沉积演化研究。工区以辫状河三角洲和滨浅湖滩坝沉积为主，沙二段平原亚相广布于斜坡外带，前缘亚相呈北东向沿斜坡中带展布；沙一段为广盆浅水环境，三角洲沉积范围较沙二段明显缩小，中期发育了一套全区最重要的烃源岩，受博野水系强物源的影响，仅在大百尺一带发育辫状河三角洲前缘沉积。斜坡中带毗邻生油洼槽的前缘砂体及雁翎、西柳地区的滩坝体系是成藏的有利区带。

STUDY ON THE SEQUENCE STRATIGRAPHY OF THE MEMBER2-MEMBER1 SHAHEJIE FORMATION IN THE NORTH-CENTRAL PART OF LIXIAN SLOPE

Based on the comprehensive study on core，seismic and logging data，the sequence stratigraphy framework is built up.The strata of the Member 2 and Member 1 of Shahejie Formation can be divided into two third-order sequences，including six system tracts with three different types：low stand system tract，extension system tract and high stand system tract.And the depositional evolution of the system tracts is analyzed.The braided fluvial delta and sand bar and beach of shallow-shore lacustrine are the main facies.The braided fluvial delta plain distributes on the outer belt of the slope，and along the middle belt of the slope the braided fluvial delta-front is widely developed during the Member 2 of Shahejie Formation.While the Member 1 of Shahejie Formation has experienced the largest transgression from the Paleogene，the delta deposit is obviously decreased.Intermediate stage of the Member 1 of Shahejie Formation ，the delta-front is developed only on the belt of Dabaichi，and the rest of the area is covered by source rocks.The braided fluvial delta-front sandbodies which include the sand bar and beach in Yanling and Xiliu，are in direct contact with oil generation depression and are the favorable exploration areas.