基于贝叶斯框架的裂缝型储层频变AVO反演及多参数预测  

Based on Bayesian Frequency-Dependent AVO Inversion for Multiple Fracture Parameters Prediction in Fractured Reservoirs

作　　者：邢慧婷 冯晅[1] 刘财[1] 郭智奇[1] 逄硕 乔汉青[1,3] Xing Huiting;Feng Xuan;Liu Cai;Guo Zhiqi;Pang Shuo;Qiao Hanqing(College of GeoExploration Science and Technology,Jilin University,Changchun 130026,China;College of Marine Geosciences,Ocean University of China,Qingdao 266100,Shandong,China;Institute of Geophysical and Geochemical Exploration,CAGS,Langfang 065000,Hebei,China)

机构地区：[1]吉林大学地球探测科学与技术学院,长春130026 [2]中国海洋大学海洋学院,山东青岛266100 [3]中国地质科学院地球物理地球化学勘查研究所,河北廊坊065000

出　　处：《吉林大学学报(地球科学版)》2025年第2期657-669,共13页Journal of Jilin University:Earth Science Edition

基　　金：国家重点研发计划项目(2022YFC3003402)。

摘　　要：裂缝型储层是一种含流体的裂缝-孔隙介质,其裂缝参数的定量表征对非常规油气藏的勘探与开发具有重要意义。然而,传统以振幅信息为主的储层预测方法存在局限性,难以全面揭示裂缝型储层的复杂特性。本文针对含饱和流体的正交裂缝型储层,深入分析了含水平和垂直正交裂缝介质的速度频散与衰减特性,并采用各向异性反射率法模拟了单界面频散砂岩储层振幅随偏移距变化(amplitude variation with offset,AVO)的频变响应特征。在此基础上,构建了以水平和垂直正交裂缝模型响应为驱动的贝叶斯反演框架,实现了对裂缝型储层中孔隙度、裂缝密度及裂缝半径的多参数定量反演。研究结果表明,孔隙度、裂缝密度及裂缝半径对速度频散表现出高度敏感性,且在低频时PP波频变反射系数随频率和入射角发生显著变化,振幅随入射角的增大线性增加,揭示了裂缝参数对频变AVO响应有重要影响。反演结果表明,所提出的反演方法在不同裂缝参数条件下,后验概率分布都具有较高精度,尤其在小尺度裂缝型储层中,对裂缝半径预测表现出更好的适用性和可靠性。Fractured reservoir is a kind of fluid-bearing fracture-porous medium,and the quantitative characterization of fracture parameters plays a critical role in the exploration and development of unconventional hydrocarbon reservoirs.However,conventional reservoir prediction methods primarily based on amplitude information are limited in revealing the complex characteristics of fractured reservoirs.This paper focuses on fluid-saturated orthogonal fractured reservoirs and thoroughly analyzes the velocity dispersion and attenuation characteristics of media containing both horizontal and vertical orthogonal fractures.An anisotropic reflectivity method is employed to simulate the frequency-dependent amplitude variation with offset(AVO)response of a single-interface dispersive sandstone reservoir.Based on this,a Bayesian inversion framework driven by the responses of horizontal and vertical orthogonal fracture models is developed to achieve multi-parameter quantitative inversion of porosity,fracture density,and fracture radius in fractured reservoirs.The results demonstrate that porosity,fracture density,and fracture radius are highly sensitive to velocity dispersion.At low frequencies,the frequency-dependent PP wave reflection coefficient exhibits significant variations with both frequency and incidence angle,and the amplitude increases linearly with the incidence angle.This highlights the substantial influence of fracture parameters on the frequency-dependent AVO response.Inversion results show that the proposed method achieves high accuracy in posterior probability distributions under varying fracture parameter conditions,with particularly improved applicability and reliability in predicting fracture radius in small-scale fractured reservoirs.

关 键 词：裂缝型储层 水平-垂直正交裂缝 裂缝参数 频变AVO 贝叶斯反演方法 

分 类 号：P631.4[天文地球—地质矿产勘探]