平行巷道条带异常体在透射槽波层析成像中造成的假象

发布时间：2018-02-27 18:39

本文关键词： 槽波透射法异常体假象层析成像　出处：《地球物理学进展》2017年06期 　论文类型：期刊论文

【摘要】：近年来透射法槽波地震勘探技术在煤矿勘探领域取得广泛应用,该技术依据槽波频散特征,对特定频率下槽波走时进行层析速度反演成像,在煤层厚度探测方面效果明显.由于煤矿巷道施工的特殊性,震源和检波器布置在巷帮煤层中,观测系统多采用两边式或三边式,导致槽波传播角度有限,容易对层析成像造成误差.在层析正演中采用最短路径与射线弯曲法联合,兼顾走时计算的精度和效率,在层析反演中进行正则化约束,利用平滑和阻尼因子提高算法的精度.通过对大量模型进行正反演发现,当煤层中存在垂直巷道异常体或局部异常体时,透射槽波层析反演不存在假象;当存在平行巷道的条带异常体时,层析结果出现交叉状速度异常假象.这是由于透射槽波采集得到的走时不受异常体位置影响,高值区在平面上表现为交叉型,导致层析反演出现假象.实际勘探施工条件允许情况下,可在煤层工作面四周布置震源和检波器消除这类假象.
[Abstract]:In recent years, the transmission groove-wave seismic exploration technology has been widely used in the field of coal mine exploration. According to the characteristics of the frequency dispersion of the groove-wave, this technique carries out the tomography velocity inversion imaging of the groove-wave travel time at a specific frequency. Because of the particularity of roadway construction in coal mine, the seismic source and geophone are arranged in the coal seam of roadway top, and the observation system mostly adopts two or three sides, which leads to the limited propagation angle of grooves. It is easy to cause errors in tomography. The shortest path combined with the ray bending method is used in the forward modeling of tomography, and the accuracy and efficiency of the travel time calculation are taken into account, and the regularization constraints are carried out in the tomography inversion. The smoothing and damping factors are used to improve the accuracy of the algorithm. Through the forward and inverse modeling of a large number of models, it is found that there is no false image when there is a vertical roadway anomaly or a local abnormal body in the coal seam. When there is a strip anomaly in parallel roadway, the cross velocity anomaly appears in the tomography result. This is due to the fact that the travel time obtained by the transmission trough wave is not affected by the abnormal body position, and the high value region appears to be cross type on the plane. If the actual exploration construction conditions permit, the seismic source and geophone can be arranged around the coal seam face to eliminate this kind of false image.
【作者单位】：河南理工大学资源环境学院;中原经济区煤层(页岩)气河南省协同创新中心;义马煤业集团股份有限公司地质研究所;中国地质大学(北京)地球物理与信息技术学院;
【基金】：国家科技重大专项项目(2011ZX05040-005) 河南省高校科技创新团队支持计划项目(14IRTSTHN002) 河南省瓦斯地质与瓦斯治理重点实验室——省部共建国家重点实验室培育基地开放基金项目(WS2017A04)联合资助
【分类号】：TD166

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