Application of Crosswell and Single Well Seismic Methods for Mapping CO2 Movement
E. L. Majer1, T. M. Daley1, R. Gritto1, V. Korneev1, and G. Li2
1Earth Sciences Division, Lawrence Berkeley National Lab, Berkeley, CA
2Geophysics, PanCanadian Resources, Calgary, AB, Canada
Two different seismic experiments at two differnt scales were conducted prior to CO2 injection for enhanced oil recovery and sequestration applications. One expereriment was conducted at Chevron’s Lost Hills California CO2 pilot project in the Belridge Diatomite. In this experiment two closely spaced vertical wells(25 meters) on either side of the CO2 injection well were used to image a 300 meter section of the diatomite formation using croswell seismic and single well seismic. Two different sources were used for both methods, a piezoelectric source (200 hertz to 3000 hertz) and a mechanical orbital vibratory ( 50 hertz to 400 hertz). The recording of the data was done with hydrophones and three component geophones. The single well used the piezoelectric source and 16 hydrophones. In the second case hydrophones deployed inside of coil tubing ( 48 channels) was used with a piezoelectric source (200 hertz to 2000 hertz)in two horizontal wells 275 meters apart and at a depth of 1350 meters with a horizontal section of 1000 meters in a carbonate formation at PanCanadian’s Weyburn field in Southern Sakatchewan to perform a high resolution crosswell experiment. In both cases the objective is to image prior and after CO2 injection to determine the path and rate of CO2 movement. In both cases high resolution images were obtained that will serve as baselines for future repeat imaging. Innovatiove methods had to be developed to successsfully deploy the seismic instruments and obtaion the high frequency data. The results to date show in the Lost Hills case the geolgic structure (bedding and faults) with indication of the induced hydrofrature between the two imaging wells. In the Weyburn case the data indicate severe wave guide effects form the reservoir section which can be used to perform dipersion tomography. Follow-up surveys in the spring of 2001 will be done to map the path of the CO2.
AAPG Search and Discovery Article #90904©2001 AAPG Pacific Section Meeting, Universal City, California