Cold Heavy Oil Production with Sand (CHOPS) has become one of the main recovery schemes for developing heavy oil reservoirs in Canada. This became possible with the introduction of progressive cavity pumps, therefore much higher sand cut in viscous heavy oil could be expected from unconsolidated/weakly consolidated formations as opposed to conventional pumps with limited capacity.
In this study, combined reservoir simulation and seismic technology are applied for a heavy oil reservoir situated in Saskatchewan, Canada, for better understanding of the reservoir properties and recovery mechanism. The numerical model was built based on the well log data and several seismic attributes. The integration of seismic attributes improved modeling reservoir heterogeneity, which is a main challenge in modeling sand production.
Firstly, we used geostatistical methods to estimate the initial reservoir porosity, using a seismic survey acquired in 1989. Secondly, sand production was modeled using erosional velocity approach and the model was run based on the oil production. Finally, results of the true porosity derived from simulation were compared against the porosity estimated from the second seismic survey acquired in 2001. This flow provides new tools that validate the simulation model results against the seismic data.
Following this approach the extent and the shape of the enhanced permeability region (wormhole region) for estimated porosity distribution are modeled. The performance of the CHOPS wells is highly dependent on the rate of creation of the high permeability zone around the wells. This method can be used for evaluating future developments of the field such as infill drilling and post CHOPS recovery methods (VAPEX).