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Title: A modeling of buoyant gas plume migration

A modeling of buoyant gas plume migration This work is motivated by the growing interest in injecting carbon dioxide into deep geological formations as a means of avoiding its atmospheric emissions and consequent global warming. Ideally, the injected greenhouse gas stays in the injection zone for a geologic time, eventually dissolves in the formation brine and remains trapped by mineralization. However, one of the potential problems associated with the geologic method of sequestration is that naturally present or inadvertently created conduits in the cap rock may result in a gas leakage from primary storage. Even in a supercritical state, the carbon dioxide viscosity and density are lower than those of the formation brine. Buoyancy tends to drive the leaked CO{sub 2} plume upward. Theoretical and experimental studies of buoyancy-driven supercritical CO{sub 2} flow, including estimation of time scales associated with plume evolution and migration, are critical for developing technology, monitoring policy, and regulations for safe carbon dioxide geologic sequestration. In this study, we obtain simple estimates of vertical plume propagation velocity taking into account the density and viscosity contrast between CO{sub 2} and brine. We describe buoyancy-driven countercurrent flow of two immiscible phases by a Buckley-Leverett type model. The model predicts that a plume of supercritical carbon more » dioxide in a homogeneous water-saturated porous medium does not migrate upward like a bubble in bulk water. Rather, it spreads upward until it reaches a seal or until it becomes immobile. A simple formula requiring no complex numerical calculations describes the velocity of plume propagation. This solution is a simplification of a more comprehensive theory of countercurrent plume migration (Silin et al., 2007). In a layered reservoir, the simplified solution predicts a slower plume front propagation relative to a homogeneous formation with the same harmonic mean permeability. In contrast, the model yields much higher plume propagation estimates in a high-permeability conduit like a vertical fracture. « less
Authors: ; ;
Publication Date:
OSTI Identifier:OSTI ID: 948573
Report Number(s):LBNL-1552E
TRN: US200907%%115
DOE Contract Number:DE-AC02-05CH11231
Resource Type:Journal Article
Resource Relation:Journal Name: International Journal of Greenhouse Gas Control
Research Org:Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
Sponsoring Org:Earth Sciences Division
Country of Publication:United States
Language:English
Subject: 54; 58; BRINES; BUBBLES; CAP ROCK; CARBON DIOXIDE; GREENHOUSE EFFECT; GREENHOUSE GASES; HARMONICS; MINERALIZATION; MONITORING; PERMEABILITY; PLUMES; REGULATIONS; SIMULATION; STORAGE; SUPERCRITICAL STATE; VELOCITY; VISCOSITY; WATER