Collaborative Research: Coupled flow-geomechanical models applied to assess earthquake triggering in tectonically active regions – The Los Angeles basin, CA

合作研究：耦合流动地质力学模型用于评估构造活动区域的地震触发 - 加利福尼亚州洛杉矶盆地

• 批准号: 2141382
• 负责人: John Shaw
• 金额: $ 30.37万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-15 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2141382&HistoricalAwards=false
• 关键词: Collaborative; Research; Coupled; flow; geomechanical

Induced seismicity, or earthquakes caused by human activities, are a growing societal concern affecting hydrocarbon and geothermal energy production, gas storage, and subsurface carbon sequestration efforts in the Unites States and throughout the world. Distinguishing between tectonic and induced earthquakes is generally straightforward in areas with little or no natural seismicity. In tectonically active regions, however, discriminating between natural and induced seismicity is far more challenging, particularly as the latter may only be detected by changes in the size, frequency, or geographic distribution of earthquakes over time. Moreover, induced seismicity in these regions poses great risks, as human activities may trigger larger and more destructive earthquakes. This study develops state-of-the-art, physics-based models to investigate how nearly a century of production and waste-water injection in hydrocarbon fields of the Los Angeles basin, California, have impacted the stability of faults in the area. These models will consider stress changes on faults caused both by tectonic and anthropogenic processes, thus helping to distinguish between tectonic and induced events. This study will advance methodologies to investigate and manage triggered seismicity in Los Angeles and other tectonically active regions, as well as address the growing concerns about induced seismicity in a tectonically active region with a population of nearly 20 million people.This project develops coupled geomechanical and multiphase fluid flow models to assess the impact of hydrocarbon production and wastewater reinjection in petroleum fields over the past century on seismic activity in the Los Angeles basin, CA. To describe the mechanical and hydraulic behavior of faults, and the influence of the change in pressure as well as full stress tensor on fault slip, this project will employ advanced techniques for modeling coupled flow and geomechanics in faulted reservoirs with a rigorous formulation of nonlinear multiphase geomechanics. These simulations will be performed in detailed models of reservoirs embedded in regional descriptions of the tectonically active fault systems in the basin. The Los Angeles basin serves as an excellent laboratory to study triggered seismicity because of its extensive field operations, wealth of fault and reservoir data, and history of induced seismicity and ground surface subsidence. We will begin the study with the Wilmington field, which has produced more that 2.5 billion barrels of oil causing up to 9 meters of ground subsidence. The researchers have gathered the complete production and injection schedules (1936-2020) for more than 5000 wells to calibrate their models with reservoir pressure and measurements of ground surface deformation. Simulations will then be expanded to the basin scale, assessing how field operations have influenced seismicity on more than 20 active strike-slip and thrust fault systems. This will include detailed analysis of seismicity patterns, including those recorded by machine learning-enabled catalogs, as well as focus on large events (e.g., 1933 Long Beach M 6.3) that occurred in the vicinity of fields. The goal is to gain an improved understanding of triggered seismicity, along with more capable modeling tools, that can be used to manage subsurface energy operations in ways that minimize seismic hazard.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

诱发的地震性或由人类活动引起的地震是影响碳氢化合物和地热能源生产，气体存储和地下碳固换工作的社会问题日益增长的关注点。在很少或没有自然地震的地区，区分构造和诱发地震通常是直接的。然而，在构造活跃的区域中，自然和诱发地震性的区分更具挑战性，尤其是因为随着时间的流逝，地震的大小，频率或地理分布的变化才能检测到后者。此外，由于人类活动可能引发更大，更具破坏性的地震，因此在这些地区引起的地震性会带来巨大的风险。这项研究开发了最先进的基于物理的模型，以研究加利福尼亚州洛杉矶盆地碳氢化合物田中的近一个世纪的生产和废水注入如何影响该地区断层的稳定性。这些模型将考虑由构造和人为过程引起的断层的压力变化，从而有助于区分构造事件和诱导事件。这项研究将推动方法论，以调查和管理洛杉矶和其他构造活跃地区的触发地震性，并解决对构造活动中诱发的地震性的日益关注，其中有近2000万人的人口。该项目发展了该项目，从而培养出了彼此的杂物和多态流动模型，以评估过时的范围越来越多的范围，以评估水文的影响，并在水上构成的影响范围内，是在水中的影响。加利福尼亚州洛杉矶盆地的活动。为了描述断层的机械和液压行为，压力变化以及完全应力张量对断层滑移的影响，该项目将采用高级技术来建模耦合流量和故障储层中的地球力学，并使用非线性多相性的严格配方。这些仿真将在嵌入盆地构造活动断层系统区域描述中的储层模型中进行。洛杉矶盆地是研究触发地震性的出色实验室，因为其广泛的现场操作，大量的断层和储层数据以及诱导的地震性和地面沉积的历史。我们将从威尔明顿田地开始进行研究，威尔明顿田中产生了更多的25亿桶石油，导致地面沉降9米。研究人员已经收集了完整的生产和注入时间表（1936-2020），以超过5000孔的井来通过储层压力和地面变形的测量来校准其模型。然后，模拟将扩展到盆地量表，评估现场操作如何影响20多个主动滑滑和推力断层系统上的地震性。这将包括对地震性模式的详细分析，包括由机器学习的目录记录的模式，以及专注于在田野附近发生的大型事件（例如，1933年的长滩M 6.3）。目的是对触发的地震性以及功能更强大的建模工具的了解，可用于以最小化地震危害的方式来管理地下能量操作。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的智力和更广泛影响的评估来进行评估来通过评估来进行支持的。