松辽盆地新民油田下白垩统泉四段浅水三角洲骨架单砂体空间发育特征

Spatial distribution patterns of single framework sand bodies of a shallow-water delta in the Cretaceous Quantou Formation of Xinmin Oilfield, Songliao Basin

以高分辨率层序地层学和储层构型理论为指导,利用岩芯、测井曲线和生产动态等资料,在沉积相分析的基础上,对松辽盆地新民油田白垩系泉四段浅水三角洲骨架单砂体空间发育特征进行系统研究并建立相关模式。研究表明,研究区泉四段主要发育浅水三角洲平原亚相和前缘亚相,分别以分支河道和水下分支河道为骨架砂体。泉四段整体处于湖平面上升的沉积背景,浅水三角洲不断向陆退积,骨架单砂体的空间发育特征表现出一定的规律性。可容空间与沉积物供应量的比值(A/S)是控制骨架单砂体空间发育特征的主要因素。A/S<<1时,发育浅水三角洲平原沉积环境,分支河道单砂体垂向叠置样式主要为侧向切叠式和垂向切叠式,平面呈连片状展布;单砂体发育规模大,平均宽度为396~463m,平均厚度为5.2~5.8m。A/S≤1时,发育浅水三角洲平原沉积环境,分支河道单砂体垂向叠置样式主要为侧向叠加式和垂向叠加式,平面呈网状展布;单砂体发育规模较大,平均宽度为308~412m,平均厚度为4.2~5.2m。A/S>>1时,发育浅水三角洲前缘沉积环境,水下分支河道单砂体垂向叠置样式主要为孤立式,平面呈枝状展布;单砂体发育规模较小,平均宽度为165~325m,平均厚度为2.4~4.0m。

Guided by the principles of high-resolution sequence stratigraphy and reservoir architecture, the spatial distribution pattern of single framework sand bodies of the 4 th Member of the Cretaceous Quantou Formation(K1q4) in the Min 36 block of Xinmin Oilfield of the Songliao Basin is studied. Some models have been established on the basis of depositional features acquired from cores, logging and production performance data. Shallow-water deltaic plain and front are well developed in the K1q4 of the study area and their framework sand bodies are mainly the deposits of distributary channels and subaqueous distributary channels respectively. Research results suggest that during the deposition of K1q4, the lake level was rising. As the results, the shallow-water delta gradually retrograded toward the land. The A/S value is the main factor controlling the spatial distribution pattern of single sand bodies. When A/S value is far less than 1, there developed shallow water deltaic plain and the vertical stacking of single sand bodies are dominated by lateral and vertical tangency, and in view of plane distribution, sandbodies are contiguous. Individual sand bodies may reach 396 to 463 meters in length and 5.2 to 5.8 meters in width on average. However, when A/S value is less than or equal to 1, the vertical stacking patterns of single sand bodies are dominated by lateral and vertical superposition. In a plane view, sandbodies are distributed in a reticular pattern. Single sand bodies are 308 to 412 meters long and 4.2 to 5.2 meters wide on average. When A/S value is far more than 1, the sand bodies are dominated by a vertical stacking pattern by separated sandbodies, in the plane view, sandbodies are distributed in a dendritic pattern consisting of sand bodies 165 to 325 meters long and 2.4 to 4.0 meters wide on average.