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/W004127/1
• 负责人: Junlong Shang
• 金额: $ 9.1万
• 依托单位: University of Glasgow
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FW004127%2F1
• 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.

地热能为加热和发电提供了化石燃料的重要替代方法。例如（增强的地热系统）使深岩层的靶向在〜2至5 km的深度以进行热量提取。但是，很少有在EGS开发的尝试达到商业阶段。最近的评论确定了全球花岗岩或其他晶体岩石中的30个EGS遗址，其中很大一部分失败了。在不产生不必要的地震性的情况下，很难开发EG。在英国，在西康沃尔郡的Carnmenellis Granite Pluton中，不成功的Rosemanowes项目在1990年代初被关闭，经过多年的液压分裂未能建立任何明显的孔间液压连接。这一失败杀死了英国的EGS研发。最近，从2019年的钻探开始，在曼联唐斯（United Downs）网站上进行了第二个项目，已经在Carnmenellis Granite中进行。但是，尽管开发商尚未发表任何正式宣布，但几个月来，英国地热社区“葡萄藤”讨论了该项目遇到麻烦的原因，涉及地震性和井之间缺乏水利联系。这项最新失败涉及损失约2000万英镑的投资，强调了对EGS的更高专业知识的需求。尽管对储层刺激进行了大量研究，但控制储层刺激期间原位应力演变的一般过程以及相关的人为地震性仍然知之甚少。例如，化学刺激如何改变断层表面的机械状态？化学反应会以有利于不稳定性的方式而产生新的二级矿物质，改变断层的摩擦特性？当材料通过溶解去除材料时，断层演变上的牵引力如何？我们如何管理流体注入率和压力以避免人为地震性？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。 We have assembled a team of enthusiastical 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.只有通过共同努力，我们才能使用完整的专业知识，高级实验室设施，独特的现场资源和站点数据来涵盖各个机构无法实现的多个规模和方面。我们将采用综合实验室，建模和现场方法来发展新的科学理解，以了解如何控制和消除受刺激的地热参与者引起的人为抗性。 UW和LBNL将使用其实验室设施领导实验研究。实验室研究将为耦合建模提供数据，该数据将由UG领导。 Scripe将领导现场研究，并从其Gonghe EGS网站中引入独特的资源和数据（在独特的Gonghe EGS网站上的实地研究将提供巨大的未来协作机会。我们还设计了外展和合作伙伴活动，以促进研究人员之间的互动和合作活动，并促进长期可持续性的协作。这些活动包括了两次现场访问。在2023年，在UG），6个在线较小的小组会议和一个项目网站。

项目成果

Stress path constraints on veined rock deformation

脉状岩石变形的应力路径约束

• DOI: 10.1016/j.rockmb.2022.100001
• 发表时间: 2022
• 期刊: Rock Mechanics Bulletin
• 作者: Shang J