• Tunnel and Underground Space
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• v.27 no.3
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• pp.146-160
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• 2017

$CO_2$ sequestration for alleviating global warming is a hot issue in the world. In this study, TOUGH2 and FLAC3D were combined for analyzing the hyro-mechanical coupling behaviors expected in $CO_2$ sequestration and applied it to Sleipner project carried out in Norway. In the analysis, the influence of pore pressure on in situ stress was considered and the influence of caprock permeability on hydro-mechanical behaviors was analyzed. In the condition of constant injection rate, pressure and saturation at the injection well, liquid and gas saturation in rock, major and minor stress variations with time and distance from the injection well, and horizontal and vertical displacements after injection could be investigated. The major principal stress was quickly increased in the early stage and then slowly decreased to a stable value, which was higher than the initial value. In contrast, the minor principal stress returned to initial value after some increase in the early stage. Surface upheaval was steadily increased and it was up to 15mm in 2 years after injection. When the caprock's permeability was changed from $3e-15m^2{\sim}3e-18m^2$, it was found that the injection well pressure and surface upheaval were inversely propotional to the permeability.

• Geophysics and Geophysical Exploration
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• v.8 no.4
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• pp.280-286
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• 2005

Geological sequestration of carbon dioxide ($CO_2$) is one of the most effective strategies far long-term removal of greenhouse gas from atmosphere. This paper reviews three projects for the $CO_2$ sequestration in geological formation. A unique $CO_2$ injection into a marine aquifer has been successfully monitored with repeated surface seismic measurements in the North Sea Sleipner West field. The seismic images reveal the extent and internal shape of the $CO_2$ bubble. Massive miscible $CO_2$ has been injected into a complex fractured carbonate reservoir at the Weyburn oil filed. High-resolution time-lapse P-wave data were successfully obtained to map the features of $CO_2$ movements within the two thin zones of different lithology. From the time-lapse crosswell EM imaging at the Lost Hills oil field in central California, U.S.A., the replacement of brine with $CO_2$ has been confirmed through a decrease of conductivity. The conductivity image was successfully compared with induction logs observed in the two wells.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.1-9
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• 2006

Geological storage of captured $CO_2$ is a new way of reducing greenhouse gas emissions to protect the climate, but is based on the established technology associated with injection of fluids underground. The geological formations of interest for this technique include operational and depleted oil and gas fields, and deep saline aquifers. Prediction of storage performance will depend on models of the behaviour of $CO_2$ in geological formations; these need to be refined and verified, and methods of monitoring developed and proved. These needs can be met through monitored demonstration and research projects. Current commercial projects that are demonstrating $CO_2$ storage include Sleipner, Weyburn, ORC, and In Salah; research projects include West Pearl Queen, Nagaoka, and Frio. In this paper, some of the monitored injection projects are described. The reservoirs employed for storing $CO_2$, and the associated monitoring techniques, are briefly reviewed. It is argued that small-scale research projects, used to develop techniques and prove models, are complementary to the large-scale monitored injections that will establish the viability of this technique for mitigating climate change.