双鱼石超深高温高压气藏偏差因子计算方法及早期储量预测

Calculation Method of Deviation Factor and Early Reserve Prediction of Shuangyushi Ultra-deep Gas Reservoirs with High Temperature and Pressure

为提高超深层高温高压气藏早期动态储量计算的准确程度,以双鱼石栖霞组气藏为研究对象,基于新型DAR方法,采用多元回归建立无因次拟对比温度、压力的自变量函数,通过与实验数据对比分析不断修正方程,进而提出新型超深层高温高压气藏偏差因子计算方程;通过文献调研和实验室测试对全直径样品进行压缩系数分析,给出了高温高压条件下储层综合压缩系数的确定方法。研究结果表明:所建立的气藏偏差因子计算新方法可提高超深层高温高压气藏早期动态储量预测准确度3.0个百分点以上;超深层高温高压气藏岩石具有微可压缩特征,其压缩系数的数量级与地层水相当;实例分析显示高温高压气藏的偏差因子预测和压缩系数的确定是早期准确计算储量的关键。研究成果可为超深层高温高压气藏早期动态储量的准确计算提供参考借鉴。

In order to improve the accuracy of early dynamic reserve calculations for ultra-deep gas reservoirs with high temperature and pressure,a new DAR method was used to establish the independent variable functions of dimensionless pseudoreduced temperature and pressure by multiple regressions based on gas reservoirs in Shuangyushi Qixia Formation which was taken as the study object,the equations were continuously revised by comparing and analyzing with experimental data,and a new calculation equation was proposed for the deviation factor of ultra-deep gas reservoirs with high temperature and pressure;the method of determining the comprehensive compression coefficient of the reservoir at high temperature and pressures was given through comparative studies and laboratory tests on full-diameter samples for compression coefficient analysis.The results of the study showed that the established new calculation method for the deviation factor of gas reservoirs could improve the accuracy of early dynamic reserve prediction of ultra-deep gas reservoirs with high temperature and pressure by more than 3.0 percentage points;the rocks in the ultra-deep gas reservoirs with high temperature and pressure were micro-compressible,and the order of magnitude of their compression coefficients was equivalent to that of formation water;the example analysis showed that the prediction of deviation factor and the determination of compression coefficient of ultra-deep gas reservoirs with high temperature and pressure were the key to early accurate reserve calculation.The results of this study can be used as a reference for the early accurate calculation of dynamic reserves in ultra-deep gas reservoirs with high temperature and pressure.