基于“三瞬”地震属性融合的煤厚预测方法研究

Research on coal thickness prediction method based on'three instantaneity'seismic attribute fusion

煤层厚度是煤及煤层气开采所关注的重要参数。本文采用“三瞬”地震属性融合的方法进行煤厚预测。通过构建煤厚变化的楔形模型,利用正演数值模拟分析揭示“三瞬”地震属性与煤厚间的映射关系。基于叠后三维地震数据体提取“三瞬”地震属性,利用改进的熵权法计算3个属性的权重值,进而融合计算2层主采煤层的厚度。对比分析验证井位置的煤厚预测与揭露结果,表明利用“三瞬”地震属性融合预测煤厚是可行的,但预测精度依赖于地震资料信噪比与层位拾取精度。因此,针对高质量的叠后地震数据体,本文的方法是煤厚预测的有效手段。

Coal seam thickness is an important parameter concerned by coal and coalbed methane mining.In this paper,the method of'three instantaneity'seismic attribute fusion was used to predict coal thickness.By constructing a wedge model of coal thickness variation,the mapping relationship between'three instantaneity'seismic attributes and coal thickness was revealed by forward numerical simulation analysis.Based on the post-stack three-dimensional seismic data volume,the'three instantaneity'seismic attributes were extracted.Improved entropy weight method was used to calculate the weight values of the three attributes,and then the thickness of the two main coal seams was calculated by fusion.The comparative analysis of the coal thickness prediction and exposure results of the verification well position showed that it was feasible to use the'three instantaneity'seismic attribute fusion to predict the coal thickness,but the prediction accuracy depended on the signal-to-noise ratio of seismic data and the accuracy of horizon picking.Therefore,for high-quality post-stack seismic data,the method in this paper was an effective means for coal thickness prediction.