Abstract: Reservoir Description and Pool Performance of Judy Creek and Golden Spike Reefs

D. Jardine

Because of complexities associated with the original conditions of deposition, enhanced by subsequent diagenesis, carbonate reservoirs usually are characterized by extreme heterogeneities of porosity and permeability.

Efficient reservoir-management plans require detailed, integrated geologic-engineering studies which can be used to develop reservoir-engineering numeric models. Continual monitoring of pool performance is essential to ensure that the geologic model is valid.

The Judy Creek and Golden Spike Devonian reef pools illustrate how the internal reservoir geometry can affect performance. At Judy Creek, a peripheral water-flood initiated in 1962 was altered to include a pattern flood in 1974 after extreme pressure gradients and geologic reservoir description indicated permeability barriers in the reef interior. This change in operating practice will result in substantial increase in expected oil recovery.

At Golden Spike a miscible flood was in operation from 1964 to 1975. This now has been terminated, as recent performance analysis indicates that numerous barriers to vertical flow in the reef interior have resulted in bypassing of oil and loss of miscible-flood benefits. Future sweep efficiency under the current gas drive is predicted to be high, because of continued drainage of oil off the barriers.

AAPG Search and Discovery Article #90968©1977 AAPG-SEPM Annual Convention and Exhibition, Washington, DC