PDF(Pubmed)
Abstract：
Seismic methods are extensively used in coal mining for expanding resource discoveries and definition as well as for mine monitoring. However, the use of borehole seismic methods is relatively uncommon due to the high cost of borehole seismic acquisition using conventional downhole tools. The introduction of distributed acoustic sensing (DAS), which uses optical fibres to record seismic data, has dramatically increased the cost-effectiveness of borehole seismic methods. Fibre-optic cables are inexpensive and, once deployed in a borehole, can be abandoned or used later for further monitoring of the subsurface. The case study presented here concerns the use of DAS to record a 3D VSP (vertical seismic profiling) for coal seam exploration in Queensland, Australia. This study trialled effective strategies for deploying cables into boreholes and demonstrated how this technology could be incorporated into the standard coal exploration process. The final processing results produced a high-resolution 3D seismic cube where the coal seams below the basalt cover are clearly identifiable around the boreholes. Permanent installation of the fibre-optic cables into a set of boreholes provides immediate benefits of 3D seismic imaging and can create additional value in utilising these sensors for further discrete or continuous subsurface measurements, including stability monitoring of underground workings and detection of methane accumulations.
摘要：
地震方法广泛用于煤矿开采，以扩大资源发现和定义以及矿山监测。然而,由于使用常规井下工具进行井眼地震采集的成本较高，因此使用井眼地震方法相对少见。分布式声学传感(DAS)的引入,使用光纤记录地震数据，大大提高了钻孔地震方法的成本效益。光纤电缆价格低廉，一旦部署在钻孔中，可以放弃或以后用于进一步监测地下。此处介绍的案例研究涉及使用DAS记录昆士兰煤层勘探的3DVSP（垂直地震剖面），澳大利亚。这项研究尝试了将电缆部署到钻孔中的有效策略，并展示了如何将该技术纳入标准煤炭勘探过程。最终处理结果产生了一个高分辨率的3D地震立方体，其中玄武岩覆盖层下方的煤层在钻孔周围可以清楚地识别。将光纤电缆永久安装到一组钻孔中提供了3D地震成像的直接好处，并且可以在利用这些传感器进行进一步的离散或连续地下测量时创造额外价值。包括地下工作的稳定性监测和甲烷积聚的检测。
