摘要
A coal seam is thin compared to the wavelength of seismic waves and usually shows strong anisotropy.It may form special geological formations,such as goafs and collapses,in coal mines.The existence of these formations may lead to instability in numerical simulations of the goaf area in a coal seam.The calculation speed of simulations is always a factor that restricts the development of simulation techniques.To improve the accuracy and effi ciency of seismic numerical simulations of goaf areas,an improved vacuum method has been incorporated into a rotated staggered grid scheme and calculations implemented by combining parallel computing and task parallelism.This ensures that the proposed numerical simulation method can be utilized in a geological model with large differences in elastic parameters among layers and improve the performance of a parallel application by enabling the full use of processor resources to expedite the calculations.We set up anisotropic coal seam models and then analyze numerically the characteristics of synthetic seismograms and snapshots of diff erent goaf areas with or without collapse.The results show that the proposed method can accurately simulate the goaf area and the calculation method can run with a high speed and parallel efficiency.The research will further advance the technology of anisotropic seismic exploration in coal fi elds,provide data for seismic inversion and build a theoretical support for coal mine disaster prediction.
煤层相对于地震子波来说较薄,通常表现强各向异性,煤矿开采中通常会形成采空区、塌陷等特殊地质体,这些问题的存在可能导致煤层采空区数值模拟不稳定,增加地震波数值模拟的难度;煤层数值模拟的计算量大、计算速度慢也是制约数值模拟技术发展的重要因素。为提高煤层采空区地震数值模拟的精度和效率,本文将改进的真空法引入旋转交错网格有限差分中,并将并行计算与任务并行相结合进行计算;确保数值模拟方法可以应用于不同层间弹性参数差异较大的地质模型,并充分利用处理器资源加快计算速度,提高并行应用的性能。论文建立各向异性煤层模型,通过数值模拟,分析采空区有无塌陷模拟的合成地震记录与波场快照的区别,结果表明使用本文提出的方法能准确对采空区进行数值模拟,并达到较高的加速比和并行效率。这一研究成果将进一步推进煤田各向异性地震勘探技术,为煤田地震参数反演提供数据,为煤矿灾害预测打下基础。
基金
This work was supported by the National Natural Science Foundation of China(Nos.41304105 and 41674135)
the Natural Science Foundation of Shaanxi province(No.2016JM4010).
作者简介
Corresponding author:Li Qin Ph.D.,associate professor.In 2011,she graduated from the earth exploration and information technology major of Chang’an university,and now works in the school of geology and environment of Xi’an university of science and technology.It is mainly engaged in the research of seismic anisotropy.Phone:13389256190.Email:eriliqin@126.com.(E-mail:eriliqin@126.com)。
