浅水湖盆三角洲前缘砂体空间结构及剩余油分布模式

Spatial Structure of Sand Body and Remaining Oil Distribution Model in Delta Front of Shallow Lake Basin

以SP油田葡萄花油层葡I油组为例,研究了基准面的变化以及旋回类型,并分析了对剩余油分布的影响。结果表明:葡I油组可分为一个长期基准面上升半旋回、一个中期基准面上升半旋回和一个中期基准面下降半旋回、5个短期基准面向上变深又变浅的对称旋回以及3个短期基准面变深的非对称旋回;浅水三角洲水下分流河道砂体频繁改道,形成复杂的空间结构。研究区的砂体垂向叠加模式可分为两端厚中间薄下部连通、一端薄中间及一端等厚上部连通、两端薄中间厚上部连通、近似等厚连通等4种;平面上砂体叠加模式可分为连片式、交切条带式及孤立条带式3种。受基准面变化的影响,垂向上剩余油主要富集在砂体较薄及夹层遮挡的部位。平面上剩余油主要分布在背物源方向及分流河道部位。

Taking PI oil group of Putaohua reservoir in SP oilfield as an example,the variation of base level and cycle type are studied,and the influence on remaining oil distribution is analyzed.The results show that the PI oil group can be divided into a long-term baseline rising half-cycle,a medium-term baseline rising half-cycle and a medium-term baseline falling half-cycle,five short-term baseline upward deepening and shallow symmetrical cycles and three short-term baseline deepening asymmetrical cycles.Shallow water delta underwater distributary channel sand bodies frequently divert,forming complex spatial structure.The vertical overlapping modes of sand bodies in the study area can be divided into four types.Two ends are thick with thin middle and connecting bottom,one end is thin as well as middle and the other end are equally thick with connecting top;two ends are thin with thick middle and connecting top;whole connection with approximately equal thickness.The overlapping modes of sand bodies in the plane can be divided into three types,the connection type,the intersection strip type and the isolated strip type.Affected by the change of datum level,the remaining oil in vertical direction is mainly concentrated in the thinner sand body and the sheltered part of interlayer.On the plane,the remaining oil mainly distributes in the direction of back provenance and distributary channel.