POLYMER FLOOD OF THE RAPDAN POOL

A polymer-flood pilot project in the Rapdan field is documented from l aboratory design and numerical simulation to production performance an d projected economics. The Rapdan field produces 10-mPa . s oil from t he Upper Shaunavon sand at a reservoir temperature of 55 degrees C. Av erage permeability is 0.114 mu m(2), average porosity is 18%, and Dyks tra-Parsons coefficient is 0.8. The field was discovered in 1953, and waterflood began in 1962. In Jan. 1986; a polymer pilot was initiated in a portion of the field with a PV of 456 x 10(4) m(3). The pilot con sists of 13 producers and 5 injectors drilled on 162 x 10(3)-m(2) spac ing. By Dec. 1994, 43% PV of a 21-mPa s poly mer solution had been inj ected into a-confined, central five spot (Wells 12-12 and 12-12A). The oil cut increased from a stable value of 8% during the waterflood to a peak value of 25%. The corresponding daily oil production increased from 8 to 28 m(3)/d. The performance of the total project oil producti on increased from 65 m(3)/d at an oil cut of 18% to a peak production of 180 m(3)/d at an oil cut of 36%. Production rate has declined from 140 m(3)/d in 1991 to 106 m(3)/d in Dec. 1994, with a corresponding oi l-cut decline from 25% to 20%.