Cold heavy oil production (CHOP) exploits the mechanism of enhanced solution gas (or foamy-oil) drive to achieve an economic oil rate and ultimate recovery. Understanding the foamy-oil dynamics and being able to simulate the process enable us to evaluate the cold production potential more realistically. This has led to the improved cold heavy oil recovery in Shell Canada's Cliffdale development in Peace River area.

A recently developed foamy-oil dynamic model has been employed to evaluate the effects of well spacing and patterns on oil recovery. The results revealed that under the foamy-oil drive, the oil recovery improves as the well spacing decreases, because of decreasing well spacing leads to faster reservoir pressure depletion and stronger foamy-oil drive. In contrast, with a conventional black-oil model, the estimated ultimate oil recovery stays constant irrespective of the well spacing, and the only benefits of down spacing would be the production acceleration.

The benefits of capturing foamy oil dynamics for the evaluation of CHOP development has been demonstrated with an example of a high level economic screening approach for the search of optimal well spacing and the number of laterals. The evolution of typical well spacing and the number of well laterals with time in the Peace River CHOP development has resulted from both the ever-increasing field operation experience and the improved understanding of foamy-oil drive dynamics.

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