Multicomponent seismic applications in coalbed methane development, Red Deer, Alberta

Sarah Elizabeth Richardson

Vertical seismic profiles obtained of Ardley coal zone strata near Red Deer, Alberta demonstrate the effectiveness of multicomponent seismic applications in coalbed methane development. Zero-offset surveys show that a broad-band mini-P vibratory source is ideal for imaging the coal zone, providing a measure of vertical continuity of the coal zone as well as delineating intra-coal events. The extraction of Vp/Vs from P-wave and S-wave seismic data yields a high Vp/Vs value in the near surface (~5), decreasing to approximately 2.5 at 300 m depth. Reflectivity values extracted from walkaway surveys demonstrate that convertedwave data better resolve the upper coal contact than compressional-wave data, as they are less affected by tuning. Numerical modelling demonstrates "proof of concept" that time-lapse seismic imaging will be able to monitor changes in the reservoir resulting from dewatering, allowing producers to optimize enhanced coalbed methane production throughout reservoir life.