针对页岩储层的多波地震各向异性预测方法研究

Due to the complicated physical properties of the reservoir, shale gas exploration using geophysics theory or methods is a difficult problem and thus arises international concern. Based on the rock physics theory of shale, we propose a research project of anisotropic multicomponent seismic inversion for the characterization of shale gas reservoir in terms of organic matter abundance and rock brittleness. We first study the amplitude response of the plane seismic wave in the anisotropic media, and then derive a group of approximations of the reflection coefficients and impedance of multicomponent seismic wave. The approximations are generalized for different anisotropic media, for example VTI, HTI and ORT, and have sufficient accuracy for relatively strong anisotropy. Based on the derived approximations, we develop the inversion scheme for multiple elastic parameters of shale gas reservoir. Quantitative interpretation of the reservoir brittleness and organic matter abundance using is also studied. This research solves the critical problem of seismic inversion for the media with relatively strong anisotropy. It not only provides the basic theory of the characterization of organic matter abundance and rock brittleness using multi-component seismic, but also helps the development of elastic parameter inversion of shale gas reservoir.

由于页岩气储层具有复杂的物性，描述页岩气储层的地震理论和方法的研究是现阶段一个国际性的难题。本项目是基于岩石物理理论，针对页岩储层的有机质含量和脆性开展的各向异性多波地震反演方法的研究。通过研究地震波在各向异性介质中的传播和振幅响应机理，建立一组在较强各向异性条件下具有高精度，并在不同各向异性介质假设下通用的多波地震反射系数和阻抗的方程；以此为基础研究适用于具有较高各向异性的页岩储层的多波地震反演方法；并进一步探索利用弹性参数对页岩储层脆性和有机质丰度进行定量解释的方法。本研究可以解决针对页岩储层的多波地震反演和储层描述的关键问题，例如待求参数具有不同敏感度，以及利用的弹性参数和地震各向异性参数解释储层脆性和干酪根含量的问题。不仅能为页岩储层的有机质丰度和可压裂性的地震预测提供理论依据，还有利于推动针对具有强各向异性的非常规能源的地震反演技术的发展。

本项目是基于岩石物理理论，针对页岩储层的有机质含量和脆性开展的各向异性多波地震反演方法的研究。研究内容涉及以下三个方面：1. 研究平面波在各向异性介质中的传播和振幅响应机理；2. 针对页岩储层的各向异性地震多波联合反演方法研究；3. 基于岩石物理理论的页岩气储层脆性和有机质含量定量解释方法。研究解决了针对具有强各向异性的页岩储层的多波地震反演和储层描述的关键问题，例如待求参数具有不同敏感度，以及利用的弹性参数和地震各向异性参数解释储层脆性和干酪根含量的问题。为页岩储层的有机质丰度和可压裂性的地震预测提供理论依据和技术支持。