Miller and others, 2005 Mid-Continent AAPG Abstract

4-D Seismic--Application for CO2 Sequestration Assurances

by Richard D. Miller, Abdelmoneam E. Raef, Alan P. Byrnes, and William E. Harrison,
Kansas Geological Survey, University of Kansas, 1930 Constant Ave, Lawrence, KS 66047.

CO2 sequestration in aquifers and oil reservoirs requires some level of confidence that the nature of gas distribution, its transport paths, and its long-term fate can be ascertained with reasonable confidence. Sequestered CO2 needs to be reliably monitored during injection and while dormant during storage. Movement of CO2 outside geologic traps is a major concern and obstacle to the acceptance and widespread use of CO2 sequestration. Time-lapse seismic is sensitive to changes in the imaged volume and could provide the necessary transport and fate assurances. Key to time-lapse monitoring of CO2 sequestration is effective reservoir modeling constrained by reasonable geologic characteristics and adapted to measured changes in the reservoir between monitor well locations. Understanding this evolution of the CO2 plume permits the necessary advancement in the complexity of reservoir models. The DOE-sponsored CO2 enhanced recovery project in central Kansas illustrates the feasibility of 4-D seismic to map CO2 as it advances through a mature oil reservoir. Injection of CO2 for enhanced recovery, begun in December 2003, exhibited delayed breakthrough response and different well response than predicted by models. Lateral heterogeneities consistent with well interference testing were revealed on baseline 3-D seismic. 4-D seismic revealed that injected CO2 was constrained in its motion both in response to the observed heterogeneities and the interaction of pressures generated by water containment injectors. Information provided by 4-D seismic can play a key role in developing accurate reservoir models and mapping the movement and stability of CO2 during sequestration.

AAPG 2005 Mid-Continent Section Meeting, "Target the Hidden Potential in the Wild West," September 10-13, 2005, Oklahoma City, Oklahoma