A.G. Putz (Elf Aquitaine Production) | Brigitte Bazin (Inst. Francais du Petrole) | B.M. Pedron (Elf Aquitaine Production)
The polymer injection in the Courtenay field has reached a mature stage as a large part of the polymer slug has been injected. The total production of oil confirms the original expectations and the operation is profitable.
The Courtenay field is an elongated layer at a depth of 600 m. The oil is viscous (40cp), water is fresh and the temperature is 30 C, making the conditions favorable for a polymer injection.
The area swept by polymer encompasses 640 000 m3. It consists of three contiguous zones with a total of 4 injectors and 18 producers. Injection of a 900 ppm solution of polyacrylamide diluted in field water started in July 1989 at a total rate of 380 m3/day. Up to now, 640 000 m3 (100 % pore volume) of solution have been injected, polymer injection was terminated in November 1993; since then, water is injected at a rate of 420 m3/day.
Compared to primary production, a strong increase in oil production has been observed. Definite tertiary oil banks breakthroughs have been observed at 14 producing wells.
The operation has been simulated with the corepol model, a 3 dimensional 3 phases simulator with polymer and tracers option.
The total oil production is well represented on a global basis but the actual quantity of polymer produced in the effluent water is lagging behind the value expected by simulation.
A full physico-chemical characterization of the polymer in the effluents of the well CY55 has confirmed that it was not degraded by its flow through the formation and the injection/production facilities.