Time-lapse VSP data processing for monitoring CO₂ injection

Time-lapse VSP data processing for monitoring CO2 injection has been reported. The baseline VSP survey was conducted before the CO2 injection. The injection is into the top portion of the Desert Creek Formation, just beneath the Gothic shale, which acts as the reservoir seal. A different monitoring scheme was used at the SACROC field. The preprocessed field data were then processed to separate the upgoing and downgoing wavefields using median filtering. Standard VSP processing steps are used to process the baseline VSP data. This combined with the better quality raw data, gives us images superior to those from the Aneth survey. This change in reflectivity stands out from the reflections of the rest of the formation away from the injection zone. Southwest Regional Partnership on Carbon Sequestration at the Aneth oil field in Utah and at the SACROC oil field in Texas.