Amplitude variation with offset and azimuth (AVOA) inversion is a mainstream method for predicting and evaluating fracture parameters of conventional oil and gas reservoirs. However, its application to coal seams is limited because of the specificity of the equivalent media model for coal—also, the traditional seismic acquisition system employed in coal fields falls within a narrow azimuth. In this study, we initially derived a P-P wave reflection coefficient approximation formula for coal seams, which is directly expressed in terms of fracture parameters using the Schoenberg linear-slide model and Hudson model. We analyzed the P-P wave reflection coefficient’s response to the fracture parameters using a two-layer forward model. Accordingly, we designed a two-step inversion workflow for AVOA inversion of the fracture parameters. Thereafter, high-density wide-azimuth pre-stack 3D seismic data were utilized for inverting the fracture density and strike of the target coal seam. The inversion accuracy was constrained by Student’s t-distribution testing. The analysis and validation of the inversion results revealed that the relative fracture density corresponds to fault locations, with the strike of the fractures and faults mainly at 0°. Therefore, the AVOA inversion method and technical workflow proposed here can be used to efficiently predict and evaluate fracture parameters of coal seams.

AVOA反演是常规油气藏裂缝参数预测与评价的主流方法。然而，由于煤炭等效介质模型的特殊性，其在煤层中的应用受到限制，而且煤田传统地震采集系统的方位角窄。在本研究中，我们初步推导了煤层PP波反射系数的近似公式，该公式使用Schoenberg线性滑动模型和Hudson模型直接用裂缝参数表示。我们使用两层正演模型分析了 PP 波反射系数对裂缝参数的响应。因此，我们为裂缝参数的 AVOA 反演设计了一个两步反演工作流程。此后，利用高密度宽方位叠前三维地震资料反演目标煤层的裂缝密度和走向。反演精度受到学生的限制t -分布测试。反演结果的分析验证表明，相对裂缝密度与断层位置相对应，裂缝和断层的走向主要在0°。因此，本文提出的AVOA反演方法和技术流程可用于高效预测和评价煤层裂缝参数。