叠前深度偏移层析速度反演技术在盐矿溶腔探测中的应用

Application of Velocity Inversion Technology of Pre-Stack Depth Migration Tomography in Salt Dissolving Cavity Detection

水溶性盐矿开采形成溶腔引发地面塌陷是盐矿生产的瓶颈。近些年东兴盐矿地区开展了大量的二维、三维地震勘探工作,大致掌握了盐矿区溶腔的发育情况以及盐层顶板破坏程度等。为了能更加准确、精细地刻画出溶腔的形态、范围、大小及发展情况,减少实际开采时造成的经济损失,应用叠前深度偏移层析速度反演技术进一步研究盐矿溶腔的发育情况。首先建立时间域初始层速度模型,然后通过层位拾取和网格化过程建立深度域层速度模型,利用层析速度反演技术不断修正和优化深度域层速度模型,得到真深度速度模型对数据体进行叠前深度偏移。对比叠前时间和深度偏移的结果,叠前深度偏移结果更加有利于圈定各个溶腔的最大平面边界、溶蚀面和平均溶蚀高度,对盐矿的开采具有重要的指导意义。

Ground collapse caused by solution cavity is the bottleneck of salt mine production.In recent years,a lot of two-dimensional and three-dimensional seismic explorations have been carried out in Dongxing salt mine area,and the development of the salt cavity and the damage degree of the salt roof in the salt mine area have been roughly grasped.In order to describe the shape scope and development of the cavity more accurately and reduce the economic loss caused by actual mining,the development of the cavity in salt mine was further studied by using the pre-stack depth migration tomography inversion technology.Firstly,the initial layer velocity model in the time domain was established.Then the velocity layer model in depth domain was established through layer picking and gridding process,and the velocity layer model in depth domain was continuously modified and optimized by using tomographic velocity inversion technology,the true depth velocity model was finally obtained for prestack depth migration of data volume.Compared with the results of pre-stack time and depth migration,the results of pre-stack depth migration are more conducive to delineating the maximum plane boundary,dissolution surface and average corrosion height of each cavity,which are contributable to the mining of salt mine.