苏里格气田苏6井区下石盒子组盒8段沉积相特征

苏6井区是鄂尔多斯盆地苏里格气田主要产气区，主产层为中二叠统下石盒子组第8段，其沉积相类型及特征长期倍受众多研究机构和学者的争议。根据钻井、测井及岩芯分析化验资料,结合前人研究成果，认为苏6井区盒8段属河流沉积体系，其中盒8下段为辫状河，盒8上段为曲流河。在深入细致的微相分析基础上，分别建立了缓坡型辫状河与多河道低弯度曲流河两种沉积模式，认为最有利的储集砂体主要为高能水道心滩和边滩叠置砂体，其次为河床滞留砂体。上述沉积相类型划分和沉积模式的建立为包括苏6井区在内的整个苏里格气田储集相带预测、储层评价以及大规模开发奠定基础。

Sedimentary Facies of the 8th Member of Lower Shihezi Formation in Su6 Area, Sulige Gas Field

Su6 area is the main gas-producing district in Sulige gas field. There is a lot of debate among institutes and scholars on the type and characteristic of sedimentary facies in the 8th member of the Middle Permian Lower Shihezi Formation which is the main gas-producing strata. According to comprehensive studies of well logs, cores and previous study, the authors conclude that the kind of depositional system is river in the 8th member of Lower Shihezi Formation and it could be further classified into two kinds as the braided-river in the lower part and the meandering-river in the upper part. Based on the deliberate analysis of microfacies, the authors set up the gentle-gradient braided river sedimentary model and the multi-channel and low-sinuosity meandering river sedimentary model, and think that the most favorable reservoir is overriding sand bodies of channel bar and point bar and channel bed sand bodies is sub-favorable reservoir. The establishment of the sedimentary facies type and sedimentary model gives a good method to favorable facies belts prediction, reservoir evaluation and exploitation in Sulige gas field including the whole Su6 area.