Dynamic Reservoir Characterization: Application of Time-Lapse (4-D), Multicomponent Seismic to a CO2 EOR Project, Vacuum Field, New Mexico
S. L. Roche1, T. L. Davis2, R. D. Benson2, and L. Duranti2
1Output Exploration, LLC
2Colorado School of Mines
A time-lapse (4-D), multicomponent (9-C), seismic data survey was acquired, processed and interpreted in conjunction with a CO2 Enhanced Oil Recovery (EOR) project at Vacuum Field, New Mexico, USA. The CO2 injection program induced bulk rock property variations due to fluid saturation and pore pressure changes associated with reservoir production processes. Seismic monitoring utilized four separate 9-C seismic surveys to form a dynamic reservoir characterization of the San Andres reservoir in the study area.
Interpretation of the P-wave and S-wave data volumes, and integration with geological and reservoir engineering data, demonstrate that changes in bulk rock properties associated with the CO2 injection program could be detected using multicomponent surface seismic data. The primary seismic attribute used to detect the 4-D response was variations in shear wave anisotropy.
Acquisition of the time-lapse (4-D), multicomponent data included generating both P-wave and S-wave energy at each source location using vibrator source units. Each receiver location recorded three components of the seismic wavefield resulting in a full 9-C seismic survey over the project area. Data acquisition of the surface seismic data was augmented with the simultaneous recording of a single, 3-C geophone, positioned in a wellbore centrally located in the survey area at a depth of 1000 m.
A data processing methodology for time-lapse, multicomponent, seismic survey was developed and applied to the P-wave and S-wave data volumes. Significant features of the data processing method are application of surface consistent processes, windowed crosscorrelation of common-trace pairs between the initial and repeat surveys with subsequent decomposition to source and receiver components, and the use of information from the downhole 3-C geophone to constrain P-wave and S-wave data processing.
AAPG Search and Discovery Article #90905©2001 AAPG Southwest Section Meeting, Dallas, Texas