(LLNL-2) Lawrence Livermore National Laboratory
Frontier Observatory for Research in Geothermal Energy
Closing the loop between in situ stress complexity and EGS fracture complexity
Lawrence Livermore National Laboratory
Principal Investigator: Dr. Kayla Kroll
Summary
Our goal is to develop, apply and validate a holistic thermal, hydrologic, mechanical, and chemical (THMC) measurement-informed numerical tool to predict long-term flow behavior and induced seismic and/or aseismic slip in enhanced geothermal system (EGS) reservoirs. We will integrate experimental and modelling approaches to reduce parameter uncertainty and better predict and mitigate seismic hazard at DOE’s Utah FORGE site and future EGS sites. This project will be led by Lawrence Livermore National Laboratory (LLNL). Dr. Kayla Kroll (LLNL - seismologist) will serve as the Principal Investigator (PI) and has assembled a highly qualified, experienced, and multidisciplinary team to implement this project, including laboratory geomechanicists, Dr. Jeffery Burghardt (Pacific Northwest National Laboratory), Dr. Luke Frash (Los Alamos National Laboratory), and Dr. Chris Marone (The Pennsylvania State University), experimental geochemist, Dr. Megan Smith (LLNL), computational geoscientist, Dr. Yue Hao (LLNL), and seismologist, Dr. Keith Richards-Dinger (University of California, Riverside).
We propose a novel approach that incorporates 3D physics-based Earthquake simulations in THMC models, herein referred to as “THMC+E” models. This capability will enable improved engineering decisions at FORGE and move EGS operations toward repeatable, robust, economically viable, and socially acceptable development. FORGE management and future EGS operators may employ results of THMC+E models for decision making purposes throughout the operation lifetime. For example, before production well installation, our THMC+E models will predict circulation scenarios and related seismic hazard for a suite of possible well locations and flow rates, thus enabling evaluation of optimal well placement. Such efforts will be conducted throughout the duration of FORGE, whereby additional laboratory experiments will constrain key model parameters and ML will reduce the size of the parameter space and the associated uncertainty. THMC+E simulations will enable exploration various circumstances that may hinder EGS success and development of mitigation strategies.
EGS energy production depends on sustained permeability and sufficient fluid flow through pre-existing or induced fractures in deep hot rock. Traditional THMC computational models of EGS systems typically account for heat and mass transport, evolving stresses, and (where convenient) geochemical alteration. However, further complexities can hinder EGS (e.g. slip induced gouge formation and reaction, associated permeability changes, induced earthquakes). Currently, there are no comprehensive and fully validated workflows that address coupled processes (e.g., geochemical alteration along engineered fractured pathways, slip-induced permeability changes, coupled THMC effects and induced seismicity) in EGS environments. Therefore, we propose to extend traditional methods to include deformation and slip in computational models to optimize EGS. We will integrate high-temperature geomechanical and frictional experiments and geochemical experimental data with exascale computations of reactive transport, geomechanics and associated seismic/aseismic displacement. This will result in an experimentally constrained THMC+E workflow that FORGE can use to contribute to DOE EERE and GTO Office goals to accelerate commercialization of EGS at reduced cost and risk of inducing seismicity.
Data & Reports
- Utah FORGE: Powder X-ray Diffraction Data from Well 16A(78)-32 Core This dataset, from Lawrence Livermore National Laboratory, consists of four raw XRD scans in RAW file format (e.g., FORGE-5477-full.raw). These files are suitable for viewing and analysis using open-source quantitative XRD software (e.g., Profex; www.profex-xrd.org ) and/or other proprietary instrument software. Additional scan and method information, as well as preliminary results of quantitative XRD (q-XRD) analysis, are contained in the accompanying XRD_metadata_LLNL_2023_FORGE_5_2428.docx file.
- Triaxial Direct Shear Results This submission includes a report and data related to triaxial direct shear results by Los Alamos National Laboratory. The data includes effluent chemistry, geomechanical data, images, and surface profiles.
Videos
Well 58-32 Well 78-32 Well 78B-32 Well 68-32 Well 56-32 Well 16A(78)-32 Well 16B(78)-32 Wells General