惠民凹陷西部老第三系沙河街组三段三角洲体系及砂岩体沉积特征和演化规律

The Evolution of Palaeogene Delta Depositional Systems and Sand Bodies in the Western Huimin Depression, Shandong Province

惠民凹陷是渤海湾地区新生代断陷盆地之一,西部地区老第三系发育完整。三角洲是最重要的沉积体系和油气聚集的有利地带,三角洲型砂岩体是研究区主要的油气储集体。沙河街组三段自下而上发育完整的深湖相—前三角洲亚相(泥页岩或浊积扇)—三角洲前缘亚相(砂岩体)—三角洲平原亚相(砂岩体)巨旋回沉积序列。本文阐述了区内沙河街期发育的若干个三角洲体系的亚、微相构成和沉积特征,重点研究了三角洲型砂岩体以及与其成因相关的浊积岩体的分布、发育样式,揭示了惠民凹陷老第三系沙河街组三段三角洲体系的形成、演化规律以及时空上和其他成因相关沉积体系的共生特征。

The Huimin depression is one of the Cenozoic fault basins around the Bohai Bay. Palaeogene strata are well developed in the western part. Deltas are the important depositional system favourable for petroleum accumulation, and the sand bodies are the major oil -gas potential reservoirs. In the Shahejie-3 Member (the No. 3 Member of the Shahejie Formation) there are developed complete megacyclic depositional successions of deep-lake (shale, clay) facies-prodelta subfacies (shale-clay stone or turbidity fans) -delta front and plain subfa-cies (sandstones). This paper presents the studies of the sedimentary facies, delta systems and their related sandstones, and reveals the depositional history of delta systems in the Palaeogene Shahejie-3 Member in the Huimin depression.