华池—南梁油田长8油藏高阻水层解释方法

Interpretation Methods for High-Resistivity Water Layer in Chang 8 Reservoir in Huachi-Nanliang Oilfield

鄂尔多斯盆地华池—南梁油田长8油藏存在高阻水层,油水层对比度低,油层识别难度大。为提高油层判识率,以大量测井、录井资料和岩石物理实验为基础,确定油藏水层高阻的主控因素。根据不同类型高阻水层测井响应特征,利用中子、密度和声波时差测井数据,评价孔隙结构,识别复杂孔隙结构型高阻水层;利用中子—密度曲线交会特征进行电性因子校正,扩大油水流体特征,有效识别复杂润湿型高阻水层。通过对不同主控因素高阻水层测井响应特征研究,采用相应测井技术方法有效识别,提高图版油水特征值的准确度和测井解释符合率。

In the Chang 8 reservoir in Huachi-Nanliang oilfield of the Ordos basin,high-resistivity water layers are present,and the contrast between oil and water layers is low,making it difficult to identify oil layers. In order to accurately identify oil layers,based on logging data and petrophysical experiment results,the controlling factors of the high resistivity of water layers were determined. According to the logging response characteristics of different types of high-resistivity water layers,by using the data of neutron,density and acoustic logging,the pore structure in the reservoir was evaluated to identify high-resistivity water layers with complex pore structures. By using the crossplot of neutron and density logging curves,resistivity was corrected,so as to enlarge the contrast between oil and water layers,and then to effectively identify high-resistivity water layers with complex wettability. Based on the analysis of the logging responses of high-resistivity water layers controlled by different factors,different techniques and methods were adopted to effectively identify these layers,and the accuracy of oil-water characteristic values in identification chart and the coincidence rate of logging interpretation have been improved.