The Moorcroft West Minnelusa Sand Unit is a confined reservoir that provides an ideal setting for evaluation of EOR technologies because there is minimal opportunity for off pattern operations to influence interpretation of results. The unit initially represented a marginal waterflood prospect with two wells (40 acre spacing) in the reservoir producing a total of 4 BOPD. Although unsupported by geological analysis, reservoir engineering. and fluid analysis suggested strongly that the two wells were producing from a common 805 ac-ft reservoir. Oil recovery and cash flow projections indicated that if the reservoir would respond to water injection, a polymer augmented process would markedly increase recovery. Design and installation of a multipurpose waterflood plant was staged to keep monetary investment and risk at a minimum until communication between the wells was demonstrated. In August, 1989, oil production increased from 3 to 6 BOPD demonstrating well communication. Thereafter, a skid-mounted water injection plant containing a dry solids feed system, liquid chemical storage and proportioning equipment, and a small triplex pump was installed. Polymer injection for volumetric sweep improvement was started in October 1989. An alkaline/polymer (A/P) process designed to reduce residual oil saturation was initiated in September 1991.

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