商河油田商三区沙二下亚段沉积微相研究

Research on Sedimentary Microfacies in the Lower Submember of Es_2 in the Third Region of Shanghe Oilfield

针对惠民凹陷商河油田商三区沙河街组二段下亚段(EsL2)储集砂体变化规律认识不清的问题,充分利用岩心、测录井资料,开展精细沉积微相研究,共识别出3种沉积亚相5种沉积微相类型,精细描述了各个小层主要沉积微相砂体特征,阐明了沉积微相的分布规律和时空演化特征。研究区为三角洲前缘、前三角洲、浅湖-半深湖沉积,随着湖平面升降和沉积物供给的变化,三角洲由西北向东南不断推进或收缩,纵向上可划分为3个旋回,即经历了3次由浅湖-半深湖演变为三角洲前缘沉积的湖退过程。由于区内砂体横向尖灭普遍,可形成较大规模的岩性圈闭,是岩性油气藏勘探的有利目标区。

In consideration of the problems of unclear understanding of changing rules of reservoir sand bodies in EsL2 of Shahejie Formation in the 3rd Region of Shanghe Oilfield of Huimin Depression,the data of cores and geologic logs were used to study fine sedimentary microfacies,3kinds of sedimentary subfacies including 5sedimentary microfacies were identified,the characteristics of major sedimentary microfacies of each sublayer were described in detail,the distribution of sedimentary microfacies and features of its spatial evolution were denoted.There existed delta front,front delta and shallow and semi-deep lake deposits developed in research area.With the changes of lake level and sediment supply,the delta has gradually extended or shrunk from the northwest to the southeast.Three cycles were identified vertically,namely it experienced three times of lake regressive processes.Due to the lateral pinchout of sand body,large scales of lithologictraps can be formed and they are the favourable areas of oil and reservoir exploration.