Using timelapse seismic to monitor the THAI™ heavy oil production process

Abstract

Toe‐to‐Heel‐Air‐Injection (THAI™) is an in‐situ combustion process that is used for the recovery of bitumen and heavy oil. It combines a horizontal production well with a vertical air injection well placed at the toe. Compressional and shear velocities for heavy oil are extremely sensitive to temperature. As the oil is heated by the combustion process the velocity decreases causing distinct time‐delay anomalies on timelapse (4D) seismic. These time‐delay anomalies indicate that the combustion front is moving from the toes of the wells, where the air injectors are located, towards the heels. Downhole thermocouples are used to measure the temperature and hence provide control/calibration points.