Fault Zone CO2 Migration Hazard during Large-Scale Geologic Carbon Storage in the Miocene Section, Gulf of Mexico
Abstract
CO2 capture, utilization and storage (CCUS) is a demonstrated technology that can be deployed at the gigaton-scale to help reduce CO2 emissions to zero by mid-century. To ensure underground CO2 containment, it is critical to assess the hazard of CO2 migration through fault zones that may be reached by the buoyant CO2 plume. Here, we present a field-scale (45x45x8km) flow simulation model of the Miocene section offshore Texas, an attractive location to store large volumes of CO2 given the adequate pore space, knowledge of the subsurface, and proximity to CO2-emitting sources. Our model contains a major, reservoir-bounding fault reaching the seabed, representative of the numerous, coast-parallel growth faults in the area. The goal of this study is to quantify CO2 migration for multiple caprock (and fault) properties, to help guide site selection and reduce fault-related CO2 migration hazard.
We develop a tailored approach to modeling fault hydraulic properties in soft siliciclastic sediments like the Miocene in the Gulf of Mexico. This includes a new methodology (PREDICT) to model the intrinsic fault permeability considering anisotropy and uncertainty, as well as spatially heterogeneous fault relative permeability and capillary pressure upscaled from laboratory-derived curves. Our computational model incorporates the fault using discrete cells, so that hydraulic properties and geometry can be explicitly represented. We compare our model results against a base-case simulation using the industry-standard approach, and show that, without shear failure, migration of CO2 through the full caprock interval is highly unlikely. This is true for both a continuous and discontinuous caprock interval.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.U43A..06S