基于贝叶斯理论和HTI介质方位地震振幅差的裂缝弱度参数反演方法  

An Inversion method of fracture weakness parameters based on Bayesian theory and azimuthal seismic amplitude-difference in HTI media

作　　者：许凯 XU Kai(SINOPEC Geophysical Research Institute Co.,Ltd.,Nanjing 211103,China)

机构地区：[1]中石化石油物探技术研究院有限公司,江苏南京211103

出　　处：《石油物探》2023年第3期507-516,共10页Geophysical Prospecting For Petroleum

基　　金：国家自然科学基金企业创新发展联合基金项目(U19B6003);中国石化十条龙课题(P21078-4)共同资助

摘　　要：在各向同性背景地层中发育有垂直裂缝的地层,其可以表征为具有水平对称轴的横向各向同性介质(HTI介质),而裂缝弱度参数可用来表征岩石裂缝密度和识别流体。为了提升基于HTI介质裂缝弱度参数反演的稳定性和准确性,提出了一种稳定、可靠的储层裂缝弱度参数反演方法。该方法以褶积模型和HTI介质反射系数近似公式为基础,通过不同方位地震数据相减的方式,求取地震振幅差异,以减少待反演模型参数的数量,进一步基于贝叶斯反演理论,通过线性化反演算法求取裂缝弱度参数的最大后验期望和协方差,实现裂缝弱度参数反演。合成数据和实际资料的测试结果表明,裂缝弱度参数反演结果和测井数据具有良好的一致性,可有效表征储层裂缝发育特征,该方法在裂缝型储层预测和表征方面具有广泛的应用前景。Formations with vertical fractures developed in isotropic background formations can be characterized as transversely isotropic media with a horizontal symmetry axis(HTI media).Fracture weaknesses can be effectively used for seismic fracture density characterizations and fluid identifications.To achieve stability and accuracy of fracture weaknesses in HTI media,a reliable reservoir fracture weakness inversion method is proposed herein.This method is based on the convolution model and the HTI media reflection coefficient approximation formula,and it reduces the number of model parameters to be inverted by taking the differences in azimuthal seismic amplitudes.Reliable fracture weakness inversion is then realized by employing the Bayesian theory using the maximum a posteriori estimation and covariance.Finally,test results obtained using synthetic and real data reveal that the inversion results are in good agreement with the logging data and that the inversion results of fracture weakness parameters can characterize the real reservoir fracture development characteristics effectively.These results demonstrate that the method has wide application prospects in the prediction and characterization of fracture reservoirs.

关 键 词：裂缝弱度参数 贝叶斯方法 HTI介质 各向异性 方位地震振幅 

分 类 号：P631[天文地球—地质矿产勘探]