考虑流体相渗的线性回归岩心饱和度校正方法——以酒东油田白垩系K1g1砂岩油藏为例

Correction Method of Linear Regression Core Saturation Considering Fluid Phase Permeability——Taking the Cretaceous K 1g 1 Sandstone Reservoir in Jiudong Oilfield as an Example

充分考虑不同流体渗流特性对岩心饱和度测量数据的影响,发现岩心饱和度的误差可分为系统误差和挥发量误差,而传统线性回归校正法将所有误差等同于系统误差,虽然简便但不够严谨。以酒东油田白垩系K1g1砂岩油藏为研究对象,以线性回归校正理论为基础,综合运用取心、相渗资料,结合多相流体渗流理论,计算地面油、水饱和度的挥发比例和挥发量,对传统线性回归校正法进行改进:在挥发量误差线性回归校正前,将地面测量的油、水饱和度拟合线的斜率还原成地下原始状态。结果表明,研究区岩心饱和度的误差主要为油的挥发损失,校正前岩心饱和度之和最大误差为61.8%,校正后满足岩心饱和度之和为100%的归一化条件。综合考虑挥发量误差和系统误差的校正方法,在满足岩心饱和度校正精度的同时,既发挥了线性回归校正法的简便优势,又使得校正结果更符合地层真实情况。

Fully considering the influence of seepage characteristics of different fluids on the measurement data of core saturation,it is found that the errors of core saturation can be divided into system errors and volatility errors.The traditional linear regression correction method equates all errors with system errors,which is simple but not rigorous enough.Taking the Cretaceous K 1g 1 sandstone reservoir in Jiudong Oilfield as the research object,based on the linear regression correction theory,comprehensively using coring and phase permeability data,combined with multiphase fluid percolation theory,the volatilization ratio and volatilization amount of surface oil and water saturation were calculated,and the traditional linear regression correction method was improved.Before linear regression correction,the slope of the fitting line of oil and water saturation measured on the ground was reduced to the original underground state.The results show that the error of the core saturation in the study area is mainly the loss of oil volatilization,the maximum error of the sum of core saturation before correction is 61.8%,and after correction its sum reaches 100%which satisfies the normalization condition.The correction method considering the volatility errors and system errors comprehensively not only satisfies the accuracy of core saturation correction,but also gives full play to the simple advantage of linear regression correction method and makes the correction results more in line with the real situation of formation.