煤层陷落柱多波地震数值模拟与成像研究

Multiwave seismic numerical simulation and imaging study on collapse column in coal seam

陷落柱是煤田勘探开发中常见的地质灾害体,陷落柱的精确探测一直是煤田安全生产研究的重点,单纯依靠常规纵波地震勘探技术难以满足现阶段煤田精细勘探的需求。多波地震勘探技术能够获得纵波和转换波地震资料,提供更丰富的波场信息,且转换波对于埋深较浅的小幅度构造有更高的分辨率,充分利用多分量地震资料可以有效的提高地震勘探的精度。本文将多波地震技术应用到煤层陷落柱研究中,利用数值方法对煤层陷落柱进行多波地震勘探模拟研究,采用弹性波有限差分方法对构建的陷落柱模型进行多分量正演模拟,然后分别对波场分离后的PP波和PS波地震数据进行叠前深度偏移成像测试。通过对两个小尺寸陷落柱模型进行多波地震数值试算表明,多波地震勘探技术是一种有效的煤层陷落柱探测方法,充分利用多波地震资料有利于查明煤层陷落柱构造,对陷落柱取得更好的勘探效果。

Collapse column is a common geologic hazards in coal mining. The accurate detection of the collapse column has always been the focus of safety production research in coalfields. It is difficult to meet the demand of fine exploration in coalfields by relying on conventional PP-wave seismic exploration technology. Both PP-and PS-wave data can be obtained in multiwave seismic exploration, which can provide more wavefield information. Moreover, PS-wave has higher resolution for some small structures in the shallow layer, so making full use of multicomponent seismic data can effectively improve the accuracy of seismic exploration. In this paper, multiwave seismic technology is applied to the collapse column in coal seam, where multiwave seismic numerical simulation study is performed for collapse column in coal seam. The elastic finite-difference method is used for multicomponent forward modeling of collapse column model, and then the prestack depth migration imaging is performed on the separated PP-and PS-waves. Multiwave seismic numerical simulation tests of two small collapse column models show that multiwave seismic exploration technique is an effective detection method for collapse column in coal seam. It is helpful to find out the collapse column structures in coal seam and obtain better exploration effects using multicomponent seismic data.