车排子凸起CHE510井区沙湾组沉积特征研究

Study on sedimentary characteristics of Shawan Formation in CHE510 well area in Chepaizi uplift

车排子凸起沙湾组作为春风油田主力层段,存在沉积类型、展布特征不明确等问题,加强其沉积特征的研究其对寻找储层甜点极为重要。采用岩心描述、薄片鉴定、测井解释等手段,对CHE510井区沙一段沉积特征进行了研究。研究得出,研究区沙一段属于辫状河三角洲前缘沉积体系,包括水下分流河道、分流间湾、河口砂坝等微相,物源来自于西南方向的车排子凸起。其中N_(1)s^(1)_(1)层和N_(1)s^(2)_(1)层主要为水下分流河道沉积,局部为河口砂坝沉积,主水流方向均为西南至东北方向。砂体的分布受控于沉积作用:N_(1)s^(1)_(1)层砂体厚度5.0~9.7 m,平均砂体厚度7.4 m,平面上,南、北两侧厚度较大,东、西两侧及中部厚度略薄;N_(1)s^(2)_(1)层砂体厚度3.8~8.1 m,平均砂体厚度5.9 m,平面上,井区中部CHE511井、东部CHE512井、CHE514井附近厚度较厚;N_(1)s^(3)_(1)层砂体厚度3.6~7.4 m,平均砂体厚度5.3 m,平面上中部厚度较薄,东、西两侧相对较厚。通过对CHE510井区沙一段沉积特征研究,可为下一步勘探部署提供地质依据。

As the main interval of Chunfeng Oilfield,the Shawan Formation in Chepaizi uplift has problems such as unclear sedimentary types and distribution characteristics.Therefore,it is very important to strengthen the study of sedimentary characteristics to find reservoir sweet spots.By means of lithological description,thin section identification,logging interpretation and other means,the sedimentary characteristics of the first member of Shahejie Formation in the CHE510 well area were studied,and the following understandings were obtained:the first member of Shahejie Formation in the study area belongs to the sedimentary system of the braided river delta front,including the underwater distributary system.The microfacies such as channel,inter-distributary bay,and estuary sand bar come from the Chepaizi uplift in the southwest.The N_(1)s^(1)_(1) and N_(1)s^(2)_(1) layers are mainly underwater distributary channel deposits,and the N_(1)s^(3)_(1) layer is mainly underwater distributary channel deposits,with local estuary sand bar deposits,and the main water flow direction is from southwest to northeast.The distribution of sand bodies is controlled by sedimentation:the thickness of the N_(1)s^(1)_(1) layer sand bodies is 5.0~9.7 m,and the average sand body thickness is 7.4 m.The sedimentary thickness of the strata on the South and north sides is large,and the thickness on the East and west sides and the middle is slightly thin.The thickness of the sand body in the N_(1)s^(2)_(1) layer is 3.8~8.1 m,and the average sand body thickness is 5.9 m.According to the analysis of the plane distribution characteristics of formation thickness in the well area,the thickness near well CHE511 in the middle,well CHE512 in the East and well CHE514 is relatively thick;the thickness of sand body in N_(1)s^(3)_(1) layer is 3.6~7.4 m,the average sand body thickness is 5.3 m.According to the analysis of the plane thickness characteristics of stratum sedimentary,the thickness in the middle of the well area is relatively thin,and the thickness in the east and west sides is relatively thick.The study on the sedimentary characteristics of the first member of Shahejie Formation in the CHE510 well area has guiding significance for the next exploration and deployment.