A time-lapse multi-offset, multi-azimuth VSP acquired as a candidate for low-cost monitoring of CO₂ injection and storage

Kristopher A. Innanen, Kevin W. Hall, Donald C. Lawton

In August 2022, CREWES returned to the field to carry out a monitoring version of the 2018 multi-offset/azimuth VSP survey referred to as the Snowflake. The purpose is to add to the datasets which enable research into CO₂ injection/storage monitoring (through, e.g., FWI methods), side-by-side comparisons of standard geophone and accelerometer sensors with both straight and helical wound fiber, and (now), enable research into methods for time lapse analysis, whether involving FWI or other methodologies. Partners Echo Seismic and HDSC worked with University of Calgary/CREWES researchers to acquire a data set designed to maximize repeatability while adding several new dimensions. For instance, two of the VSP azimuths were re-shot with low-dwell as opposed to linear sweeps. Observing differences in effectiveness in waveform and standard analysis methods between these two sweep types is expected to shed significant light on optimal monitoring. This globally unique dataset, coupled with its baseline 2018 counterpart, is expected to support years of groundbreaking research.