Alkaline/Surfactant/Polymer Pilot Performance of the West Central Saertu, Daqing Oil Field

Abstract

SummaryA tertiary pilot application of the alkaline/surfactant/polymer (ASP) process was initiated in Sept. 1994 in the west central area of Daqing oil field. The pilot pattern consists of four inverted five-spots, including four injectors, nine producers, and 2 observation wells, encompassing an area of 90 000 m2 and with a pore volume (PV) of 203 300 m3. The target layer is the Saertu II1.3 (SII1.3) sandstone, with an average porosity of 26% and permeability of 1.426 [m2. The crude-oil viscosity is 11.5 mPa • s at reservoir temperature and the connate-water salinity is 6800 mg/L. The pilot performance shows a pronounced response from ASP injection. The average pilot area oil production rate increased from 36.7 to 91.5 m3/d, while water cut decreased from 82.7% to 59.7%. For the central well Po5, which is surrounded by injection wells, the oil production rate increased from 3.7 to 27.1 m3/d, while water cut decreased from 84.0% to 45.8%. Numerical simulation results forecast that the oil recovery will be increased by 18.1% original oil in place (OOIP). Total pilot oil production as of March 1996 is 67 500 m3 of which 25 300 m3, or 18.3 % OOIP, is additional produced oil with the current oil cut of 29.7%.