基于密井网和井间示踪剂资料的浅水三角洲单砂体沉积构型研究——以东营凹陷胜坨油田二区沙二段1-2砂组为例

浅水三角洲分流河道和河口坝砂体平面上常呈连片状，难以准确划分其单砂体，限制了剩余油分布的精准预测，制约了油田采收率的进一步提高。基于岩心和测井等资料，借助密井网和井间示踪剂数据，系统表征东营凹陷胜坨油田二区沙二段1-2砂组浅水三角洲单砂体沉积构型特征。研究结果表明：胜坨油田二区沙二段1-2砂组发育浅水三角洲沉积，包括浅水三角洲平原亚相和浅水三角洲前缘亚相，发育分流河道、溢岸、河口坝、滩坝等微相。浅水三角洲砂体划分为4个构型级次（5～8级），本次研究的单砂体属于8级构型单元。综合利用密井网和井间示踪剂数据，识别了单砂体的6种侧向接触样式：河道-溢岸-河道拼接式、河道-河道切叠式、滩坝-滩坝拼接式、河口坝-河口坝拼接式、坝上河道切割河口坝式和泥岩分隔式。井间示踪剂资料显示，坝上河道切割河口坝式侧向接触样式砂体连通性最好，其次为河道-河道切叠式、河口坝-河口坝拼接式和滩坝-滩坝拼接式，最差为河道-溢岸-河道拼接式。建立了研究区浅水三角洲单砂体沉积构型模式，其中浅水三角洲平原微相类型主要为分流河道和溢岸，单一分流河道砂体间接触样式主要有侧向切叠、侧向与溢岸砂体相连、垂向叠加和斜列叠加4类；浅水...

Study on sedimentary architecture of single sand body in shallowwater deltas based on dense well pattern and interwell tracer data： A case study of Es21 and Es22 in Shenger District of Shengtuo Oilfield，Dongying Sag

Sand bodies in distributary channels and mouth bars of shallow water deltas are often distributed in continuous sheets， mak‐ing it difficult to accurately classify the single sand body， limiting the accurate prediction of remaining oil distribution and restricting the further enhanced oil recovery （EOR）. Based on core， well logging， and other data， the characteristics of the sedimentary architectures of single sand bodies in shallow water deltas in the 1^st Submember of the 2^nd Member of the Eocene Shahejie Formation （E s₂1）and the 2^nd Submember of 2^nd Member of the Eocene Shahejie Formation（E s₂2）in Shenger District of Shengtuo Oilfield，Dongying Sag were systematically analyzed by using dense well pattern and interwell tracer data. The results show that shallow water delta deposits are developed in Es₂21 and Es₂22 in Shenger District of Shengtuo Oilfield，Dongying Sag，including plain subfacies and front subfacies of shallow water deltas. In addition， microfacies such as distributary channels，overbanks，mouth bars，and beach bars are developed.The sand bodies of shallow water deltas were divided into four architecture units （Levels 5-8）， and the single sand bodies in this study belong to the level-8 architecture unit. Six types of lateral contact patterns between single sand bodies were identified by comprehensively using dense well pattern and interwell tracer data：channel-overbank-channel splicing type，channel-channel cutting and stacking type，beach bar-beach bar splicing type， mouth bar-mouth bar splicing type，channel on dam cutting mouth bar type，and mudstone separating type. Interwell tracer data show that the sand body has the best connectivity in the channel on dam cutting mouth bar type，followed by channel-channel cutting and stacking type，mouth bar-mouth bar splicing type，and beach bar-beach bar splicing type. The worst connectivity is from the channel-overbank-channel splicing type. Finally，the sedimentary architecture models of single sand bodies in shallow water deltas in the study area were established. The microfacies type of the shallow water delta plain is mainly a distributary channel. The contact patterns between sand bodies in a single distributary channel mainly include lateral incising and overlapping，lateral contact with sand bodies on an overbank，vertical superposition，and oblique superposition. The microfacies types of sand bodies in the shallow water delta front are distributary channels，mouth bars，and beach bars. The contact patterns between sand bodies in a single mouth bar include vertical superposition，lateral splicing，oblique superposition，and mudstone separation. Two types of lateral splicing and vertical superposition exist between sand bodies in a single beach bar.