Lunchbox Geophysics

CO2 Storage and EOR: Monitoring Injection with Time-lapse VSPs

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Marcia L. Couëslan
Schlumberger Carbon Services

Tuesday, November 13th, 2007 – 11:00 AM MST
Aquitaine Auditorium, +15 level of 540 - 5 Avenue SW

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LunchBox Geophysics is free! Simply bring your own lunch (refreshments provided) and enjoy.


Many of Western Canada's major oil and gas fields have been depleted through primary production and secondary recovery methods. Oil and gas companies are now investigating new methods, such as CO2 flooding, to further enhance oil and gas recovery in the province. Injecting CO2 into a reservoir enhances oil recovery (EOR), reduces water usage, and has the potential benefit of CO2 sequestration thereby reducing greenhouse gas emissions into the atmosphere. However, the injected CO2 must be monitored to show that it is being trapped in these reservoirs and is not leaking back to the surface – particularly if the project has a planned storage component.

At the Penn West pilot project, 100 km southwest of Edmonton, Alberta, CO2 is being injected into the Cardium Formation in the Pembina Oil Field for enhanced recovery and carbon sequestration purposes. The injected CO2 is being monitored using a sparse multicomponent surface seismic program coupled with a borehole seismic array. Together, these provide lateral coverage of the survey area as well as high-resolution images near the observation well. The baseline survey was acquired in March 2005 prior to CO2 injection. The first monitor survey was acquired in December 2005 after eight months of CO2 injection. Comparisons between the baseline and monitor borehole seismic surveys show an increase in reflectivity at the reservoir, and crosscorrelations on several of the lines show systematic time shifts on the order of 0.2 ms. This time shift is in the range predicted by the Gassmann modelling.


Marcia Couëslan obtained her undergraduate degree in geological engineering from the University of Waterloo. Upon graduation, she worked as a geophysicist for Schlumberger in Houston, Texas processing both surface and borehole seismic data for 5 years. In 2004, Marcia left her job in Houston to pursue a Master's of Science at the University of Calgary with the CREWES research group. Her thesis focused on the processing and interpretation of the time-lapse VSP data that was acquired at the Penn West Energy Trust CO2-EOR Monitoring and Storage Project in Alberta. Marcia is now the senior geophysicist with Schlumberger Carbon Services in North America and is part of the technical team conducting the initial site characterization and planning monitoring programs for CCS projects. She is a member of the SEG and CSEG.