塔里木盆地哈得逊油田东河砂岩隔夹层特征及其石油地质意义

Interlayer Features and Petroleum Geology Meaning of Donghe Sandstones in the Hadson Oilfield

以石炭系东河砂岩段为主要目的层的塔里木盆地哈得逊油田在勘探开发过程中显现出油藏流体性质差异大、油水关系复杂等现象。研究中注意到东河砂岩段砂岩输导层中存在的隔夹层与相邻正常储层差异明显,遂通过岩心观察及钻井试油资料分析,明确了隔夹层形态、岩石学成分及成岩作用等特征,进而分析了隔夹层对储层中流体流动及物质交换所起的作用。哈得逊油田东河砂岩中钙质隔夹层与其相邻储层岩石骨架颗粒组成基本一致,但正常储层成岩作用复杂,而隔夹层中基本上只发育方解石、白云石及硬石膏等胶结物的胶结作用,往往导致钙质隔夹层物性极差,并造成隔夹层上下的原油及地层水性质的明显差异。综合分析认为,研究区石炭系东河砂岩段砂岩输导层内流体分布不均、流动性复杂的原因是隔夹层对流体流动的非均匀阻隔作用的结果。

The Hadson Oilfield, whose main reservoir is Carboniferous Donghe sandstones, has the problems of strong heterogeneity in reservoir fluid properties and complex oil-water relationships. Aimed to interpret the differences between interlayers and their around normal reservoirs in Donghe sandstones, through detailed core samples observation and analysis of well testing data,this article analyzed the geometry of interlayers, their petrologic elements and diagenesis, and pointed out their influences on fluid flow and materials interchange. This study indicates that elements of rock skeleton in calcareous interlayers and their around reservoirs are basically unanimous. However, because of the differences in diagenesis process, the cements in interlayers are usually calcite, dolomite and anhydrite. The cements can make the physical property of calcareous interlayers very poor, and they can also make significant property differences in crude oil and formation water which located above and below the interlayers. Based on the above analysis, the barrier effects on fluid flow of the interlayers of different degree lead to the properties of uneven distribution of fluid and complex fluid flow in the Donghe sandstone in the Hadson Oilfield.