中文摘要：

渤中25-1油田位于渤海湾盆地渤中坳陷南部,其主力油层为古近系沙河街组沙二段。在岩心观察的基础上,结合测井、录井及地震资料综合分析,认为沙二段发育辫状河三角洲和湖泊2种沉积相类型;由于距离物源较远,研究区内主要发育辫状河三角洲前缘亚相和滨浅湖亚相。沙二段沉积时的古地貌北高南低,早期水体较浅,主要发育由西南部低洼处向东北部隆起区超覆的滨浅湖滩坝砂体;随着构造沉降、水体加深,来自西南物源的辫状河三角洲前缘砂体向东北方向不断推进,最终占据了研究区的主体,滩坝砂体则逐渐萎缩至消亡;沙二段沉积末期,研究区西部BZ25-1-1井区发生局部构造抬升遭受剥蚀,导致该井区完全缺失沙二段,周边井区也有不同程度的厚度缺失。

英文摘要：

BZ25-1 Oilfield is located in the south of Bozhong Depression,Bohai Bay Basin and the main pay zone is the Member 2 of Paleogene Shahejie Formation. Based on core observation,as well asdata of well log and seismic,it is suggested that two facies,braided river delta facies and lake facies,were developed in the Member 2 of Shahejie Formation. Due to long distance from the provenance,subfacies of braided river delta front and shallow lake were mainly developed in the study area. During the depositional period of the Member 2 of Shahejie Formation,the palaeogeomorphy in the study area shows that it was higher in the north and lower in the south. During the early stage of the depositional period of the Member 2 of Shahejie Formation,the lake was shallow and there were mainly beach-bar sand bodies overlapping from lowland in the southwest to the uplifted area in the northeast. Along with tectonic subsidence and lake water deepening,the braided river delta front sand bodies prograded from the southwest to the northeast,and finally became dominant in the study area,whereas beach-bar sandbodies faded out gradually. During the late stage,the BZ25-1-1 wellblock located in the west part of the research area uplifted,which resulted in the total lack of the Member 2 of Shahejie Formation in this wellblock,as well as partial erosion in adjacent areas.