Ultrasonic imaging of a heavy oil recovery model
Kevin W. Hall, Eric V. Gallant, Malcolm McKellar, Charles P. Ursenbach, Robert R. Stewart
High-frequency (ultrasonic) acquisition over a glass bead-pack heavy oil model was conducted in early 2001. The model was built by the Department of Chemical and Petroleum Engineering at the University of Calgary, to study gravity drainage of reduced viscosity heavy oil at reservoir temperatures and pressures. Mobility of the heavy oil was improved by injection of a propane/methane mixture.
After the experiments were complete, a variety of ultrasonic surveys using 1 MHz piezoelectric transducers were conducted. These included 2D reflection lines (equivalent to a 2D stack), 2D walk-aways (equivalent to a 2D shot gather), a 3D transmission survey, and a 3D reflection survey. The purpose of acquiring these data was to determine if physical conditions within the model could be obtained by ultrasonic methods, which could lead to these properties being detected in the field using seismic methods.
The contact between the injected propane/methane mixture and undiluted heavy oil is clearly visible on the ultrasonic data as a polarity change in the reflection interpreted to be the contact between an acrylic face plate and a glass bead-pack containing these fluids in its pore spaces. Due to absorption and timing, reflections other than primaries, multiples and converted waves from the back of the acrylic are not obviously imaged in the reflection data. However, a velocity of 1918 m/s for the bead-pack plus heavy oil can be measured from the transmission data, and is compared to a theoretical value of 1720 m/s.