NI: DEEPHEAT: Digging deep Earth for heat to promote environmental sustainability

NI：DEEPHEAT：挖掘地球深处的热量以促进环境可持续发展

• 批准号: NE/W004127/2
• 负责人: Junlong Shang
• 金额: --
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FW004127%2F2
• 关键词: NI; DEEPHEAT; Digging; deep; Earth

Geothermal energy provides an important alternative to fossil fuels, both for heating and for electricity generation. EGS (enhanced geothermal systems) enables the targeting of deep rock formations, at ~2 to 5 km depth for heat extraction. However, few attempts at EGS development have reached the commercial stage. A recent review identifies ~30 EGS sites in granites or other crystalline rocks worldwide, a large proportion of which have failed. One main reason is difficulty in developing EGS without generating unwanted seismicity. In the UK, the unsuccessful Rosemanowes project, in the Carnmenellis granite pluton in west Cornwall, was shut down in the early 1990s, after years of hydraulic fracturing failed to establish any significant inter-well hydraulic connection. This failure killed UK EGS R&D for a generation. Most recently, starting with drilling in 2019, a second project - at the United Downs site - has proceeded in the Carnmenellis granite. However, although the developer has not yet made any official announcement, for months the UK geothermal community 'grapevine' has discussed reasons why this project is in trouble, involving both seismicity and the lack of hydraulic connection between wells. This latest failure, involving the loss of a ~£20 million investment, highlights the need for greater expertise in EGS. Despite the body of research on reservoir stimulation, the general processes that govern the evolution of in-situ stress during reservoir stimulation, and the associated anthropogenic seismicity, still remain poorly understood. For example, how does chemical stimulation change the mechanical state of a fault surface? Will chemical reactions, creating new secondary minerals, alter the frictional properties of a fault in a manner that favours instability? How does the traction on a fault evolve as material is removed by dissolution? How do we manage fluid injection rates and pressures to avoid anthropogenic seismicity? This project aims to create a new multidisciplinary environment and identify key scientific questions that need to be addressed to mitigate risks of failure for future EGS projects. We have assembled a team of enthusiastic early-career and more senior researchers with high international standing and expertise in geoscience, geomechanics, and geophysics, from University of Glasgow (UG) in the UK, University of Wisconsin-Madison (UW) and Lawrence Berkeley National Laboratory (LBNL) in the USA, and Sinopec Research Institute of Petroleum Engineering (SRIPE) in China. Only by working together, can we use our complementary expertise, advanced laboratory facilities, unique field resources and site data to cover multiple scales and aspects that cannot be achieved by individual institutions. We will apply integrated laboratory, modelling and field approaches to develop new scientific understanding of how anthropogenic seismicity caused by geothermal reservoir stimulation can be controlled and eliminated. UW and LBNL will lead the experimental study using their laboratory facilities. The laboratory study will provide data for coupled modeling, which will be led by UG. SRIPE will lead field study and bring in unique resources and data from their Gonghe EGS site (the first and the most important EGS site in China). The field study at the unique Gonghe EGS site will provide vast future collaboration opportunities. We have also designed outreach and partnership activities to facilitate interaction and collaboration between researchers, and to develop long-term sustainable collaborations. These activities include two site visits (to Gonghe EGS site), annual 2-day workshops (in 2022 at UW and in 2023 at UG), 6 online smaller group meetings, and a project website. We expect this project will have significant impact on public and governmental attitudes to EGS in the UK and worldwide by contributing to evidence-based seismicity control and thus to breaking the existing pattern of EGS project failure.

地热能是化石燃料的重要替代品，既可用于供暖，也可用于发电。EGS（增强型地热系统）能够针对约 2 至 5 公里深度的深层岩层进行热量提取。然而，EGS 开发的尝试却很少。最近的一项审查确定了全球花岗岩或其他结晶岩中的约 30 个 EGS 站点，其中很大一部分都失败了，因为在英国很难在不产生不必要的地震活动的情况下开发 EGS。位于康沃尔郡西部 Carnmenellis 花岗岩岩体的 Rosemanowes 项目在多年的水力压裂未能建立任何重要的井间水力连接后于 20 世纪 90 年代被关闭，这一失败导致了英国 EGS 近一代人的研发。从 2019 年开始钻探，第二个项目（在 United Downs 现场）已经在 Carnmenellis 花岗岩中进行，但开发商尚未进行任何开采。根据官方公告，几个月来，英国地热界“小道消息”一直在讨论该项目陷入困境的原因，涉及地震活动和井之间缺乏水力连接，这一最新的失败，涉及损失约 2000 万英镑的投资，凸显了这一点。尽管对油藏改造进行了大量研究，但人们对油藏改造过程中控制地应力演化的一般过程以及相关的人为地震活动仍然知之甚少。刺激改变断层表面的机械状态？化学反应会产生新的次生矿物，从而以有利于不稳定的方式改变断层的摩擦特性吗？当物质被溶解去除时，断层上的牵引力会如何演变？该项目旨在创建一个新的多学科环境，并确定需要解决的关键科学问题，以减轻未来 EGS 项目失败的风险。具有较高国际水平的资深研究人员来自英国格拉斯哥大学 (UG)、美国威斯康星大学麦迪逊分校 (UW) 和劳伦斯伯克利国家实验室 (LBNL) 以及中国石化石油工程研究院 (LBNL) 在地球科学、地质力学和地球物理学方面的声誉和专业知识（只有通过共同努力，我们才能利用互补的专业知识、先进的实验室设施、独特的现场资源和现场数据来覆盖单个机构无法实现的多个尺度和方面，我们将应用一体化的实验室、建模和现场。华盛顿大学和劳伦斯伯克利国家实验室将利用其实验室设施进行实验研究，以开发新的科学认识，以了解如何控制和消除地热储层刺激引起的人为地震活动。该实验室研究将为耦合建模提供数据，该实验将由 UG 领导。 SRIPE 将领导现场研究，并从共和 EGS 站点（中国第一个也是最重要的 EGS 站点）引入独特的资源和数据。独特的共和 EGS 站点的现场研究将为我们提供广阔的未来合作机会。还设计了外展和伙伴关系活动，以促进研究人员之间的互动和合作，并发展长期可持续的合作，这些活动包括两次实地考察（共和 EGS 现场）、每年为期 2 天的研讨会（2022 年在华盛顿大学和 2023 年在华盛顿大学）。 UG）、6 个在线小组会议和一个项目网站，我们预计该项目将有助于基于证据的地震活动控制，从而打破英国和世界范围内公众和政府对 EGS 的态度。 EGS 项目失败的现有模式。