--> ABSTRACT: Nonconventional Drilling in Prudhoe Bay Field, by Doug B. Dickey; #91030 (2010)

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Nonconventional Drilling in Prudhoe Bay Field

Doug B. Dickey

Nonconventional wells are an important part of the development plan for the Prudhoe Bay field. Each of the three types, (1) high angle, (2) horizontal, and (3) drain hole, have specific applications in the field. Geologic criteria for well selection include faulting, vertical permeability heterogeneities, and structural dip. Initial production rates are up to five times greater than that of a conventional well.

The original justification for the wells included increased productivity, reduced gas and water coning, additional oil recovery, access to thin or geometrically isolated reservoir intervals, and increased drainage areas. These benefits are tempered by the increased drilling and completion costs, limited workover potential, and surveillance complexity.

At Prudhoe Bay, nonconventional wells have been drilled in peripheral areas--the gravity drainage area--and are planned for minor reservoir development. Five horizontal wells and nine high-angle wells have been drilled to date. Although the performance of these wells has been impressive, the benefits of reduced coning and additional recovery are yet to be realized.

The economics of nonconventional wells is dependent on the future cost of workovers, the actual additional recovery, long-term performance, and the future price of oil. In the near term, the wells have proven to be highly productive and valuable as a means to reach peripheral accumulations that would not otherwise be developed.

AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.