特低渗透油层有效厚度确定方法研究

Determination of effective thickness for oil reservoirs with extra-low permeability

利用自然伽马、自然电位、声波时差、密度、中子、微电极等多种测井曲线,结合岩心分析、地质及试油等资料综合对比研究,分析和识别了影响陕北斜坡地带特低渗透储层参数变化的背景值及有效油气成分,并结合目的层段钙质和泥质夹层的定量统计分析,建立了一种确定特低渗透油层有效厚度的物性、电性下限和不同类型夹层的扣除标准。对该区目的层段80多口井特低渗透储层进行了精细评价处理,合理地剔除了钙质夹层、泥质夹层、致密层、干砂层和不够标准的差油层,确定了各井油层的有效厚度,提高了该区目的层段油藏测井解释和有利区预测的精度。

On the basis of core analyses, geological and well testing data, the background value and effective oil and gas component influencing the variety of characteristics of oil reservoirs with extra-low permeability in Shaanbei Slope were analyzed and identified by many kinds of logging curves. The elimination criterion of physical and electrical properties cutoffs and various interlayer for determining the effective thickness of oil layers with extra-low permeability was proposed on the basis of numerical and statistic analyses of calcareous interlayer and muddy interlayer in the studied layers. The fine evaluation and treatment on more than 80 wells in a certain extra low permeability reservoir were made by eliminating the calcareous interlayers, muddy interlayers, tight layers, dry sands and under-standard poor layers. The thickness of oil layers in every well was determined. This method can guarantee the precision of log interpretation and prediction of favorable zones in the layers.