多重孔隙介质地震岩石物理模型构建及孔隙结构表征

Carbonate, tight sand and shale reservoir belong to multi-porosity medium, whose pore structure characterization is a key problem for seismic reservoir prediction and fluid identification. This project takes multi-porosity medium as target, aims to the relationship between pore structure and elastic parameters of multi-porosity medium, and carries theory and method study on rock physics modeling and pore structure characterization for multi-porosity medium. Based on the effective medium theory and pore elasticity theory, this project establishes the rock physics model for multi-porosity medium to study the elastic properties of rocks with complex pore structure. From the rock physics model of multi-porosity medium, the project builds a new parameter for characterizing the pore structure, to reveal the relationship between the pore structure and elastic parameters, and determines the elastic parameters which are sensitive to the pore structure. By the relationship between the pore structure and elastic parameters, the project establishes the objective function between the elastic parameters and pore structure parameter, and develops a method of combined utilization of multiple elastic parameters for inverting the pore structure parameter to characterize the pore structure of rocks. By studying the theory and method of characterizing the pore structure of rocks, the project lays a foundation for multiple porosity medium reservoir prediction and fluid identification.

碳酸盐岩、致密砂岩和页岩均属多重孔隙介质储层，其孔隙结构表征是地震储层预测和流体识别的难点。本研究以多重孔隙介质为对象，针对岩石孔隙结构与弹性参数之间的定量关系这一科学问题，开展多重孔隙介质地震岩石物理模型构建及孔隙结构表征理论与方法研究。基于岩石物理等效介质理论和孔隙弹性理论建立多重孔隙介质地震岩石物理模型，分析复杂孔隙结构储层的岩石物理响应特征；利用多重孔隙介质地震岩石物理模型构建一种新的孔隙结构参数，建立岩石孔隙结构与弹性参数之间的定量关系，明确能够敏感反映岩石孔隙结构的弹性参数；建立岩石孔隙结构参数与弹性参数之间的目标函数，联合利用多种弹性参数反演岩石孔隙结构参数，实现储层孔隙结构表征。通过研究岩石孔隙结构表征理论与方法，为多重孔隙介质储层预测与流体识别奠定基础。

多重孔隙介质储层孔隙类型多样，孔隙结构复杂，非均质性很强。本项目针对多重孔隙介质孔隙结构与地震特征之间定量关系的科学问题，开展了多重孔隙介质地震岩石物理模型构建及孔隙结构表征理论与方法研究。基于等效介质理论和孔隙弹性理论，结合临界孔隙度模型和Kuster-Toksöz方程，构建了包含多种孔隙类型的多孔可变临界孔隙度模型，理论模型和实验测试数据验证了多孔可变临界孔隙度模型能够适用于多重孔隙介质地震岩石物理建模；利用多孔可变临界孔隙度模型，构建了新的岩石临界孔隙度参数来表征岩石的孔隙结构，建立了新的岩石临界孔隙度参数与岩石孔隙形状（孔隙纵横比）之间的关系，在传统的岩石物理模板上增加岩石孔隙形状一维，除了传统的岩石孔隙度以及孔隙流体饱和度之外，考虑岩石孔隙形状对其弹性特征的影响，揭示孔隙形状与岩石地震弹性参数的之间变化规律；构建了储层地震弹性参数（纵波速度、横波速度和密度等）与新的临界孔隙度参数之间的目标函数，利用储层地震弹性参数反演新的临界孔隙度参数，进而利用新的临界孔隙度参数来表征储层的孔隙结构，指导识别裂缝与溶洞储层。通过研究岩石孔隙结构与地震弹性参数的定量关系，为多重孔隙介质储层预测与流体识别奠定理论基础。