基于测井岩石力学参数计算砂泥岩储层含气饱和度的新方法

为提高砂泥岩含气储层测井精细解释的符合率,研究了利用测井岩石力学参数计算其含气饱和度的方法(以下简称新方法)。基于岩石体积物理模型和体积弹性模量,推导了岩石体积压缩系数、孔隙流体体积压缩系数及气体压缩系数的计算式,建立了含气饱和度计算模型。以S气田砂泥岩储层测井数据为基础,对比分析了由新方法、Archie公式和物性分析等3种方法计算得到的含气饱和度,并与试气结论进行了对照评价。研究表明,在气层、差气层,用新方法计算的含气饱和度与Archie公式、物性分析得到的结果的平均误差分别为3.5%、4.0%,三者数值上差别不大;在差油层、干层,用新方法计算的含气饱和度与其他2种方法得到的结果差别较大,但其与试气产量相一致,显示出了新方法的优势。研究认为,利用测井岩石力学参数计算砂泥岩储层含气饱和度的新方法,可作为Archie公式计算含气饱和度的有效补充。 

A New Method to Calculate the Gas Saturation of the Sand and Shale Formations Based on Logging Rock Mechanics Parameters

To improve the precision of interpretation of gas reservoir to correlate with the rate of logging, a study using logging rock mechanics parameters to calculate gas saturation of sand and shale rock formations was carried out(hereinafter referred to as the new method).Based on the physical volume in the rock model and the bulk modulus, the formulas of volume compressibility, the fluid compressibility and gas compressibility factors were deduced, and a gas saturation calculation model was established.Based on the logging data in S gas field, the gas saturation results were calculated by the new method, the Archie formula, the Physical Analysis were contrasted, and a controlled evaluation with gas testing conclusion was conducted.The study revealed that the average error of the gas saturation calculated by the new method with the gas saturation from the Archie formula, and the gas saturation from the Physical Analysis in the gas zone was 3.5%, and the poor gas reservoir was 4.0%, the values of the saturation were quite the same.The values of the saturation calculated by new method were quite different with another two methods in dry layer and poor reservoir, but the same with the gas testing result.This proved the advantages of the new method.Studies suggested that this method of calculating the gas saturation could be used as an effective complement to Archie formula.