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    应用预测压缩走时表优化算法实现高效微地震偏移叠加定位

    Efficient microseismic migration stacking localization using a predictive compression algorithm for traveltime table optimization

    • 摘要: 针对微地震定位中大规模三维走时表存储开销大、读取负担重及数据访问效率低等问题,在利用快速推进法生成规则网格走时表的基础上,引入误差约束预测压缩(squeeze,SZ)算法,构建了“走时表计算—压缩存储—解压恢复—偏移定位”一体化技术流程,并将压缩走时表嵌入联合震源机制反演的偏移叠加定位程序。结合结合图形处理器(GPU)加速偏移叠加定位框架,从数据访问层与偏移定位求解层两个方面,分析压缩走时表对事件检测、成像聚焦和定位整体流程效率的影响。三维Overthrust模型数据和实际地面微地震监测数据测试结果表明,SZ算法能够在误差受控条件下显著减小走时表大小,在事件检测曲线、成像峰值位置和空间定位结果上,压缩走时表与原始走时表高度一致,误差约束预测压缩方法能够在保证定位精度的前提下,显著提升大规模微地震偏移叠加定位流程的处理效率。

       

      Abstract: To address the large storage overhead, heavy reading burden, and low data-access efficiency of large-scale 3D traveltime tables in microseismic localization, we introduce the error-bounded predictive compression (squeeze, SZ) algorithm to regular-grid traveltime tables generated using the fast marching method, and establish an integrated workflow of "traveltime computation, compressed storage, decompression, and migration localization", which embeds the compressed traveltime tables into a migration stacking localization program with joint source-mechanism inversion. Using a GPU-accelerated migration stacking localization framework, we analyze the influences of compressed traveltime tables on event detection, imaging focusing, and overall localization efficiency at both the data-access and localization-solving layers. Tests on synthetic microseismic data from the 3D overthrust model and field monitoring data show that the SZ algorithm significantly reduces the size of traveltime tables under controlled error conditions. Moreover, the compressed traveltime tables remain highly consistent with the original ones in terms of event-detection curves, imaging-peak positions, and spatial localization results. These results demonstrate that the error-bounded predictive compression method significantly improves the overall processing efficiency of large-scale microseismic migration stacking localization while preserving localization accuracy.

       

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