Hazard potential of leaking faults during geologic carbon sequestration
Abstract
Risk assessment methods are used to guide decision making during all phases of a carbon storage project, from initial site design and permitting all the way through shut-in and long-term maintenance. Unfortunately, significant science gaps exist in our understanding of the behavior of CO2 storage reservoirs, leading to very large uncertainty bounds. In this work, we examine one key driver of risk: the potential for leakage out of a storage interval along a permeable fault zone. Two key factors complicate this assessment and must be addressed: (1) fault zones are known to exhibit very complicated multiphysics behavior, and (2) direct characterization of the constitutive properties of a fault zone is typically unavailable. In this work, we will present a computational model for the behavior of a leaking fault connecting a saline storage reservoir and a groundwater aquifer. The model includes both full compositional flow behavior, as well as hydromechanical changes leading to a strain-dependent permeability, addressing several key multiphysics couplings. This deterministic fault model is then used within a UQ sampling framework in order to rigorously quantify the sensitivity of the output response to the input model parameters---that is, brine/CO2 leakage rates as a function of the input constitutive properties and boundary conditions. We will focus on the implications of these sensitivities for cost-effective characterization and monitoring campaigns, as well as for guiding site operations. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.H51G1269W
- Keywords:
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- 1822 HYDROLOGY / Geomechanics;
- 1849 HYDROLOGY / Numerical approximations and analysis;
- 1873 HYDROLOGY / Uncertainty assessment