EI二阶导数的储层参数和流体模量反演方法  

Inversion for reservoir parameters and fluid bulk modulus using the second-order derivative of EI

作　　者：蒋志恒 陈怀震 刘垒 蔡纪琰 JIANG ZhiHeng;CHEN HuaiZhen;LIU Lei;CAI JiYan(CNOOC China Limited Tianjin Branch,Bohai Petroleum Research Institute,Tianjin 300452,China;Tongji University,State Key laboratory of Marine Geology,School of Ocean and Earth Science,Shanghai 200092,China)

机构地区：[1]中海石油(中国)有限公司天津分公司渤海石油研究院,天津300452 [2]同济大学海洋地质国家重点实验室,海洋与地球科学学院,上海200092

出　　处：《地球物理学报》2023年第9期3854-3868,共15页Chinese Journal of Geophysics

基　　金：上海市自然科学基金项目(21ZR1464700);上海市扬帆计划项目(20YF1451000);中央高校基本科研业务费项目资助。

摘　　要：储层孔隙度、泥质含量及流体类型估测是地球物理勘探的重点及难点问题.基于岩石物理理论及等效模型,可以构建油气储层反射特征与储层孔隙度、泥质含量及流体的映射关系.本文从流体替换模型出发,结合矿物平均模型,首先推导了以孔隙度、泥质含量、流体模量和密度表征的非线性反射系数及弹性阻抗公式;然后根据推导的反射系数和弹性阻抗公式,建立了一套两步法反演策略:利用部分角度叠加数据进行线性反演预测弹性阻抗体;利用预测的弹性阻抗体开展泥质含量、孔隙度、流体模量和密度等变量的非线性反演,引入弹性阻抗对于反演变量的一阶和二阶导数以提高反演的精度.最后,利用层状模型验证了新推导的反射系数方程的精度,并分别利用测井数据模型生成的含噪声合成地震记录及实际工区地震数据验证了所提出的反演方法的可靠性.Estimation of reservoir porosity,clay volume and fluid type plays an important role in geophysical exploration.Based on petrophysical theory and equivalent models,the relationship between seismic wave reflection and reservoir porosity,clay volume and fluid is constructed.Combining fluid substitution model and the average model for calculation of effective moduli of minerals,we first derive the nonlinear reflection coefficient and elastic impedance(EI)that are expressed as a function of porosity,clay volume,fluid bulk modulus and density;and using the derived reflection coefficient and elastic impedance formula,we propose a two-step inversion strategy,which involves:(1)using partially incidence-angle-stacked seismic data to implement a linear inversion to predict EI datasets;(2)using the predicted EI datasets to implement a nonlinear inversion for unknown parameter vector that involves clay volume,porosity,fluid modulus and density,during which we compute the first-and second-derivatives of EI with respect to unknown parameters to improve the accuracy of the inversion.Finally,the accuracy of the newly derived reflection coefficient is verified by a two-layer model,and the reliability of the proposed inversion method is verified using noisy synthetic seismic gathers generated by a well log model and the real seismic data.

关 键 词：岩石物理 孔隙度 泥质含量 流体模量 叠前地震反演 

分 类 号：P631[天文地球—地质矿产勘探]