Hydrophone cable acquisition and imaging
Jitendra S. Gulati, Robert R. Stewart, Brian H. Hoffe
This paper investigates the feasibility of using hydrophone detectors to acquire VSP data. The interest in hydrophones stems from the fact that they offer a rapid and efficient way for acquiring VSP data.
With this objective, CREWES acquired seismic data using hydrophone detectors in a 100m cased and water-filled hole over the Blackfoot field in Alberta, Canada. The data was simultaneously acquired with several 2-D seismic surveys over the field.
Events on raw hydrophone data correlate with corresponding geophone receiver gather. Tube waves are observed to be the primary source of noise on the hydrophone data. They are effectively suppressed using a combination of predictive deconvolution and velocity filters. VSPCDP stacking and migration are then used to obtain the final section from the hydrophone data. Correlation and interpretation of the hydrophone image with those from previously interpreted 2-D and 3-D surface seismic surveys reveal the anomaly associated with the channel structure in the Blackfoot field. In this survey, hydrophones in boreholes resulted in efficient acquisition of VSP data and interpretable images.