Fiber Optic Distributed Acoustic Sensing for Stress Measurement and Mitigation of High Stress Hazards at Depth

用于深度压力测量和减轻高应力危险的光纤分布式声学传感

• 批准号: RTI-2021-00326
• 负责人: Eberhardt, Erik
• 金额: $ 10.93万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=718834
• 关键词: Fiber; Optic; Distributed; Acoustic; Sensing

The stress conditions present in the ground at depth are one of the most important inputs in rock engineering design. It dictates many important decisions such as the optimal orientation of horizontal wells for geothermal and unconventional gas development, as well as the orientation, dimensioning and support of underground excavations for mining, hydroelectric dams and nuclear waste repositories to ensure safety. Yet despite its importance, it is also the most difficult parameter in rock engineering design to reliably measure. This has led to numerous stress measurement techniques being developed, each with significant limitations and reliability issues. The emergence of fiber optic sensing capabilities offers several advantages that have the potential to overcome these challenges and add important improvements. For this, a Distributed Acoustic Sensing (DAS) fiber optic testing system is being requested to allow lab-scale experiments required to advance innovation to develop a new fiber optic stress measurement technique. The addition of this equipment will allow for stand-alone benchtop testing as well its integration with an existing state-of-the-art rock testing system capable of reproducing the stress, temperature and fluid pressure conditions encountered on deep mining and energy development projects. This will allow us to support our other research programs and student training focussed on improving safety and mitigating hazards related to these activities. The importance of this research is of direct relevance to Canada's economy, as well as the training of the next generation of engineers and geoscientists for our mining and energy sectors. For example, several Canadian mines are approaching depths of 3000 m exposing them to high stress hazards in the form of rockbursting. This has significant safety implications that could impact the economic viability of these mines, especially without improvements in the reliability of stress measurements at these depths. Canada's nuclear waste management program is now searching for a site for a deep repository with the geological conditions necessary to satisfy safety requirements. Assessing the stresses present and potential for rock failure is essential to ensure that the host rock serves its intended purpose of acting as a low permeability barrier to prevent the ingress of water and escape of waste. Hydraulic fracturing operations to enable production from Canada's unconventional gas reservoirs have been subject to public and regulator concerns regarding induced seismicity. These are heightened by knowledge gaps in our understanding of fault slip mechanisms and the factors controlling the likelihood and magnitude of induced seismicity. The experimental equipment being requested in this proposal will help us to accelerate our research programs addressing these challenges by allowing us to image the stress and strain patterns associated with brittle rock deformation and failure.

地下深处存在的应力条件是岩石工程设计中最重要的输入之一。它决定了许多重要的决策，例如地热和非常规天然气开发的水平井的最佳方向，以及采矿、水力发电大坝和核废料储存库的地下挖掘的方向、尺寸和支持，以确保安全。尽管它很重要，但它也是岩石工程设计中最难可靠测量的参数。这导致了许多压力测量技术的发展，每种技术都存在很大的局限性和可靠性问题。光纤传感功能的出现提供了多种优势，有可能克服这些挑战并带来重要的改进。为此，需要分布式声学传感 (DAS) 光纤测试系统来进行实验室规模的实验，以推进创新，开发新的光纤应力测量技术。添加该设备将允许进行独立的台式测试，以及与现有最先进的岩石测试系统的集成，该系统能够再现深部采矿和能源开发项目中遇到的应力、温度和流体压力条件。这将使我们能够支持我们的其他研究项目和学生培训，重点是提高安全性和减轻与这些活动相关的危险。 这项研究的重要性与加拿大的经济以及我们采矿和能源部门下一代工程师和地球科学家的培训直接相关。例如，加拿大的几个矿井深度接近 3000 米，使其面临岩爆形式的高应力危险。这具有重大的安全影响，可能会影响这些矿山的经济可行性，特别是在没有提高这些深度应力测量可靠性的情况下。加拿大核废料管理计划目前正在寻找一个具有满足安全要求所需地质条件的深层储存库地点。评估存在的应力和岩石破坏的可能性对于确保主岩达到其预期目的至关重要，即充当低渗透性屏障，以防止水的进入和废物的逸出。加拿大非常规气藏的水力压裂作业一直受到公众和监管机构对诱发地震活动的关注。由于我们对断层滑移机制以及控制诱发地震活动的可能性和震级的因素的理解存在知识差距，这些问题更加严重。该提案中要求的实验设备将使我们能够对与脆性岩石变形和破坏相关的应力和应变模式进行成像，从而帮助我们加快应对这些挑战的研究计划。