ISSN 1004-4140
CN 11-3017/P

基于正演模拟的煤层采空区地震响应特征

Seismic Response Characteristics of Coal Goaf Based on Forward Modeling

  • 摘要: 上组煤采空区对于下组煤的成像和安全回采有着重要影响,有必要研究矿区上组煤采空区精准成像技术。对于实际采空区及其下组煤的地震响应特征预测来说,建立和实际地质情况相吻合的正演模型是基础。根据搜集到的研究矿区钻孔测井资料,获取建模所需的等效地层物性参数、采空区垮落带等效模量、裂隙带等效模量等数据,建立与研究矿区地质情况比较接近的地质模型;通过正演模拟,对水平叠加剖面、偏移剖面地震响应进行分析,采空区波场特征表现为时间延迟、振幅变化、频率降低且对下部反射波有明显影响,干采空区的影响时差大于含水采空区的影响时差;通过不同地震属性的提取分析,发现采空区的地震属性明显区别于正常煤层,干采空区的地震属性和正常煤层的地震属性间差别更大。

     

    Abstract: Since the goaf of the upper coal group has an important influence on the imaging and safe mining of the lower coal group, it is necessary to study the accurate imaging technology of the goaf of the upper coal group in the mining area. For the prediction of the seismic response characteristics of the actual goaf and its subgroups of coal, the establishment of a forward model consistent with the actual geological conditions is the basis. In this paper, based on the logging data collected in the mining area, relevant data of modeling are obtained, and a geological model is established which is close to the geological situation of the mining area. Through the forward modeling, the horizontal superposition section and the migration section are analyzed. The characteristics of the wave field in the goaf are time delay, amplitude change, frequency reduction and significant influence on the lower reflected wave. Besides, the time difference in the dry goaf is greater than that in the water-bearing goaf. Through the extraction and analysis of different seismic attributes, it is found that the seismic attributes of the goaf are obviously different from those of the normal coal seam, and the seismic attributes of the dry goaf are more different from those of the normal coal seam.

     

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