Fibre-optic distributed Acoustic Sensor Technology for seismic Monitoring During shale gas Extraction (FAST-MoDE)

水力刺激过程中的微地震监测允许操作员在裂缝扩展时监测裂缝的发展。然后，他们可以优化自己的运营，同时确保以环境安全的方式进行。目前，微震活动的监测要么是使用放置在专用监测钻孔中的地震检波器，要么是使用地表密集的传感器阵列。这些方法成本高昂，可能会带来后勤挑战。在某些环境中，监测还受到检波器在高温和高压下的性能的限制。因此，在北美，微地震监测阵列通常部署在不到25%的压裂作业中。需要改进微地震监测系统，使操作员能够以经济和后勤可行的方式在大多数(或所有)水力压裂现场部署有效的微地震阵列。这将使他们能够优化这些地点的碳氢化合物开采，同时确保他们以对环境负责的方式运营。井内部署光纤布线作为分布式声波传感器(DAS)解决了上述成本和后勤问题，并显示出作为微震监测工具的巨大潜力。在这种情况下使用光纤DAS需要开发能够处理这种新类型数据的新的数据处理算法。该项目将开发定制的DAS仪器工作流程，供石油和天然气公司和微震服务公司使用。雪佛龙是世界上最大的跨国石油和天然气公司之一，该公司定期进行水力刺激活动，他们正在探索使用光纤DAS作为微地震监测工具。在该项目期间开发的新型处理工作流程的使用将使雪佛龙能够在其运营部门中增加光纤作为微地震监测工具的应用。页岩气运营商必须向环境局(EA)和石油和天然气管理局(OGA)提交水力压裂计划(HFP)以供批准，然后才能进行水力压裂。EA强烈建议使用微地震监测来绘制刺激过程中裂缝的生长情况。因此，为确保法规遵从性，环境保护局必须发展有效评估提交给该机构的微震监测计划的能力。由于HFP将包括监测地震事件的提案，监管机构需要这一快速发展领域的最新知识来评估运营商提交给他们的材料。通过密切合作，该项目将使环境保护局能够确定拟议的微地震部署，包括光纤监测，是否满足监管要求。目标的主要项目是：1.通过与从设备供应商(Silixa)到数据处理再到最终用户(Chevron)的整个供应链建立伙伴关系，开发光纤DAS数据处理工作流程。2.为监管者制定评估微震监测计划的工具和准则，包括英国水力压裂的DAS技术。这些目标将通过三个工作包实现。2.将对目前用于处理地震检波器数据的微地震处理工作流程进行调整，以适用于DAS光纤数据。处理工作流程将针对大数据量进行优化，因为任何适合用途的处理方法都必须能够处理大数据量。通过举办研讨会、开发可纳入其流程的工具以及短期安置在EA，向英国页岩气行业监管机构灌输新知识。随着英国首批页岩气开采点将于今年开始水力压裂，该项目对英国页岩气行业未来的成功尤为及时和重要，对英国经济具有巨大的潜在价值。

Microseismic monitoring during hydraulic stimulation allows operators to monitor the development of fractures as they propagate. They can then optimise their operations, while ensuring that they are conducted in an environmentally safe manner. Presently, microseismicity is monitored either using geophones placed in dedicated monitoring boreholes, or dense sensor arrays at the surface. These methods are costly, and can pose logistical challenges. In certain settings, monitoring is also limited by the performance of geophones at high temperatures and pressures. As a result, microseismic monitoring arrays are typically deployed for less than 25% of fracturing operations in North America.Improvements in microseismic monitoring systems are needed, allowing operators to deploy effective microseismic arrays at most (or all) hydraulic fracturing sites in an economically and logistically viable manner. This will enable them to optimise hydrocarbon extraction at these sites, while ensuring that they operate in an environmentally-responsible manner. In-well deployment of fibre-optic cabling as a Distributed Acoustic Sensor (DAS) addresses the cost and logistical problems outlined above and has shown significant potential as a microseismic monitoring tool. The use of fibre-optic DAS in this context requires the development of novel data processing algorithms capable of handling this new type of data. This project will develop bespoke DAS instrumentation workflows, to be used by oil and gas companies and microseismic service companies. Chevron, one of the world's largest multinational oil and gas companies, regularly conduct hydraulic stimulation activities and they are exploring the use of fibre-optic DAS as a microseismic monitoring tool. Use of the novel processing workflows developed during this project will enable Chevron to increase the uptake of fibre-optic as a microseismic monitoring tool amongst their operational divisions. Shale gas operators must submit a Hydraulic Fracturing Plan (HFP) to the Environment Agency (EA) and Oil and Gas Authority (OGA) for approval before hydraulic fracturing can take place. The EA strongly recommends the use of microseismic monitoring to map the growth of fractures during stimulation. To ensure regulatory compliance, the EA must therefore develop the capacity to efficiently evaluate microseismic monitoring plans submitted to the agency. Since an HFP will include a proposal to monitor for seismic events, regulators require up-to-date knowledge in this rapidly developing field to assess material submitted to them by the operators. Through close collaboration, this project will allow the EA to determine whether proposed microseismic deployments, including fibre-optic monitoring, satisfy regulatory requirements. The main project of objectives are to: 1. Develop processing workflows for fibre-optic DAS data through partnerships with the full supply chain from equipment supplier (Silixa), to data processing, to end-user (Chevron). 2. Develop tools and guidelines for regulators for the assessment of microseismic monitoring plans including DAS technology for hydraulic fracturing in the UK.These objectives will be achieved by through three work packages.1. Microseismic processing workflows currently used to treat geophone data will be adapted for application to DAS fibre-optic data.2. The processing workflows will be optimised for use with large data volumes because any fit-for-purpose processing method must be capable of handling large data volumes.3. Embed new knowledge in the regulators of the shale gas industry in the UK through a workshop, development of tools for inclusion in their processes and a short-term placement at the EA.With the first UK shale gas sites due to begin hydraulic fracturing this year, this project is particularly timely and important for the future success of the UK shale gas industry, with significant potential worth to the UK's economy.