Assessing the Geomechanical Response of CO₂ Disposal in Flood Basalt Reservoirs

Technical Report · Fri Nov 30 04:00:00 EST 2018

DOI:https://doi.org/10.2172/1483374· OSTI ID:1483374

Pollyea, Ryan M. ^[1]; Benson, Sally M. ^[2]

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1. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Department of Geosciences, Virginia Polytechnic Institute and State University
2. Stanford Univ., Stanford, CA (United States)

In this work, we complete a multi-scale investigation of the physical processes governing geologic CO₂ sequestration in basalt reservoirs. This work integrates (i) laboratory measurements of relative permeability in a basalt fracture, (ii) theoretical modeling to understand how relative permeability uncertainty affects geomechanical performance attributes of basalt reservoirs, (iii) outcrop-scale simulation to identify the characteristics of vertical CO₂ flow in a basalt fracture network, and (iv) regional-scale assessment of permeability architecture in the Columbia River Basalt Group (CRBG). These individual studies are combined into a site-scale stochastic model of geologic CO₂ sequestration in the Columbia River Plateau, which shows how bulk and relative permeability variability affects geomechanical reservoir integrity and storage capacity of flood basalt reservoirs. This project resulted in a novel laboratory technique that combines X-ray CT and micro-PET scanning to calculate the relative permeability curves for a horizontal fracture in basalt. We also discovered that permeability on the Columbia River Plateau exhibits directionally-dependent spatial correlation, which our analysis suggests is a result of loading-induced subsidence. This analysis further discovered that permeability in the CRBG may increase at depth due to bending moment stresses. In the context of CO₂ sequestration, this result implies that storage capacity and injectivity may actually increase at depths beyond ~1 km. Our outcrop-scale investigation found that buoyant, free-phase CO₂ tends to accumulate at fracture intersections, which inhibits vertical flow over 10+ year timescales and may facilitate both physical and chemical trapping as fluid mobility decreases. At the site-scale, we find that in flood basalt reservoirs the spatial configuration of reservoir permeability exhibits substantial control on CO₂ injectivity. We utilized known borehole geology from the Wallula Basalt Sequestration Pilot Project to develop 50 equally probable permeability configurations and found that a single injection well operating at 95% of the borehole breakout pressure can deliver 0.12 to 2.0 million metric tons of CO₂ per year (MMT CO₂ per year). This maximum injection rate can support a 1,000 MW gas-fired power plant with a single injection well.

• Research Organization: Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
• Sponsoring Organization: USDOE Office of Fossil Energy (FE), Clean Coal and Carbon (FE-20)
• DOE Contract Number: FE0023381
• OSTI ID: 1483374
• Report Number(s): DOE-VT--FE0023381
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
Carbon capture and sequestration
Columbia River Basalt Group
TOUGH3
relative permeability