砾岩储层电成像测井表征方法及应用--以准噶尔盆地玛湖凹陷砾岩油藏为例

Characterization Method and Application of Electrical Imaging Logging in Conglomerate Reservoir:A Case Study in Mahu Sag of Junggar Basin

准噶尔盆地玛湖凹陷砾岩油藏电成像测井资料丰富,为了充分利用高分辨率电成像在岩石组分、非均质性以及储层结构表征方面的优势,开展了砾岩储层电成像测井资料处理方法及深化应用研究。依据砾岩储层电成像上岩石组分电阻率的差异,通过岩心标定确定了电阻率截止值,构建了砾石、砂质和泥质含量的计算方法及伪粒度概率累计曲线的粒度分析方法;通过数理统计,构建了分选系数、孔隙度、裂缝孔隙度、高分辨率电阻率的计算方法。基于对砾岩储层主控因素的认识,提出了利用岩性组分因子、电成像测井孔隙度、非均质性因子、裂缝因子等参数评价砾岩储层储集性能的储能指数,构建了基于电成像视地层水电阻率谱方差与储层指数识别储层流体性质的新方法。研究结果表明,电成像测井资料可以有效评价砾岩储层的物性、含油性,应用于油田勘探评价,能取得较好的效果,为砾岩储层电成像测井资料的深化应用提供了借鉴。

Because the conglomerate reservoir in Mahu Sag of Junggar Basin has rich electrical imaging logging data,the processing method and further applications of electrical imaging logging data for conglomerate reservoirs were studied to make full use of the advantage of high-resolution electrical imaging in rock composition,heterogeneity,and reservoir structure characterization.Considering the resistivity difference of rock compositions in electrical imaging of conglomerate reservoirs,the cut-off value of resistivity was determined through core calibration,and the calculation method for the relative content of gravel,sand,and argillaceous parts as well as the grain size analysis method of cumulative pseudo-grain-size probability curves were constructed.Through mathematical statistics,the methods for calculating the sorting coefficient,porosity,fracture porosity,and high-precision resistivity were established.Based on the understanding of the main controlling factors of conglomerate reservoirs,it was proposed that the energy storage indexes for evaluating the reservoir performance of conglomerate reservoir could be used to develop a new method for identifying reservoir fluid properties by the variance of apparent formation water resistivity spectra and reservoir indexes on the basis of electrical imaging.The energy storage indexes mainly included the rock composition factor,porosity of electrical imaging logging,heterogeneity factor,and fracture factor,etc.The research results show that the electrical imaging logging data can effectively evaluate the physical properties and oil-bearing properties of conglomerate reservoirs,with good application effects in evaluation of field exploration.It has provided a reference for further application of electrical imaging logging data in conglomerate reservoirs.