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: 2141316
• 负责人: Ruben Juanes
• 金额: $ 35.31万
• 依托单位: Massachusetts Institute of Technology
• 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=2141316&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.

诱发地震，或人类活动引起的地震，是一个日益增长的社会关切，影响着美国和世界各地的碳氢化合物和地热能生产、天然气储存和地下碳封存工作。在自然地震活动很少或根本没有活动的地区，区分构造地震和诱发地震通常很简单。然而，在构造活跃区，区分自然和诱发地震活动的难度要大得多，特别是因为后者可能只能通过地震的大小、频率或地理分布随时间的变化而被发现。此外，这些地区的诱发地震活动带来了巨大的风险，因为人类活动可能会引发更大、更具破坏性的地震。这项研究开发了最先进的、基于物理的模型，以调查加利福尼亚州洛杉矶盆地碳氢化合物油田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上的应力变化，从而有助于区分构造事件和诱发事件。这项研究将提出调查和管理洛杉矶和其他构造活动区触发地震活动的方法，并解决人们对拥有近2000万人口的构造活动区诱发地震活动日益关注的问题。该项目开发了耦合的地质力学和多相流体流动模型，以评估过去一个世纪以来油田的碳氢化合物生产和污水回注对加州洛杉矶盆地地震活动的影响。为了描述断层的力学和水力行为，以及压力变化和满应力张量对断层滑动的影响，该项目将采用先进的技术来模拟断裂油藏中的渗流和地质力学，并采用严格的非线性多相地质力学公式。这些模拟将在嵌入盆地构造活动断裂系统的区域描述中的详细油藏模型中进行。洛杉矶盆地由于其广泛的野外作业、丰富的断层和储层数据以及诱发地震活动和地面沉陷的历史，是研究触发地震活动的优秀实验室。我们将从威尔明顿油田开始研究，该油田已经生产了超过25亿桶石油，造成了高达9米的地面沉降。研究人员收集了5000多口井的完整生产和注水时间表(1936-2020年)，以根据油藏压力和地表变形测量来校准他们的模型。然后，模拟将扩展到盆地规模，评估野外作业如何影响20多个活动的走滑和逆冲断裂系统的地震活动。这将包括对地震活动模式的详细分析，包括机器学习目录记录的地震活动模式，以及重点关注在油田附近发生的大事件(例如1933年长滩6.3级地震)。目标是更好地了解触发地震活动，以及更强大的建模工具，这些工具可以用来以最大限度地减少地震危险的方式管理地下能源作业。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。