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Abstract

A laboratory study was conducted to determine the potential for paraffin deposition for three oils from offshore Angola discovery fields using drill stem test fluids. Additional tests were conducted to select an effective paraffin inhibitor and determine the appropriate chemical dosage.

Using the test results, the engineering design group planned for storage and injection of the chemical and pigging for the flowlines and pipelines.

The proposed paraffin control measures were implemented as the fields were brought on production. Coordination and planning by production. Coordination and planning by personnel from drilling, producing, personnel from drilling, producing, engineering and the laboratory allowed implementation of an effective paraffin control program from the start-up of production. production

Introduction

Three fields were discovered offshore of Angola in 1984 and 1985. Oils from other fields along the African coast have historically been highly paraffinic and required extensive chemical and/or heat creating methods for paraffin control. Refinery analyses of the three new oils revealed significant paraffin concentrations.

The possibility of paraffin deposition had to be taken seriously, since the development plan called for 53 miles of subsea pipeline plan called for 53 miles of subsea pipeline to be added to the 13 miles already in place connecting an existing field to the onshore terminal (Figure 1). Production rates for these fields was estimated to total 36,000 bopd. Seabed temperatures were predicted to be as low as 60 degree F. For these reasons, he investigation of potential paraffin problems was critical.

A detailed laboratory study of the three oils (Crude A, Crude B, and Crude C) was conducted to confirm that paraffin deposition would occur. Test results were used to plan an a program for paraffin control, including chemical treatment and modifications to the design of the production facilities. production facilities. P. 737

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