Time-lapse interferometric imaging using an active source

• Main Author: Johansen, Asbjørn Lund
• Format: Others
• Language: English
• Published: Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk 2007
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1632

The purpose of time-lapse seismic processing is to relate changes in seismic signals to changes in reservoir parameters. A synthetic time-lapse experiment has been conducted in order to provide a controlled test environment for an interferometric imaging algorithm. The time-lapse contrast is created by introducing a 51% increase in water saturation to a model by Gassmann fluid substitution. A time-convolution algorithm was then applied on the dataset to verify the pre-processing steps, prior to applying the interferometric method. This method was also used to recursively remove time-lapse responses from the output data. The time-convolution method has been successful in recursively removing the time-lapse responses as it passes through the contrast in the media, leaving only the difference reflections below. It was found that the interferometric method responds well to the contrast of the reservoir, and shows a trend in accordance with expectations from the theory.