ALKALINE SURFACTANT/POLYMER PILOT PERFORMANCE OF THE WEST CENTRAL SAERTU, DAQING OIL-FIELD/

A 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, in cluding four injectors, nine producers, and 2 observation wells, encom passing an area of 90 000 m(2) and with a pore volume (PV) of 203 300 m(3). The target layer is the Saertu II1-3 (SII1-3) sandstone, with an average porosity of 26% and permeability of 1.426 mu m(2). 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 ra te increased from 36.7 to 91.5 m(3)/d, while water cut decreased from 82.7% to 59.7%. For the central well Po5, which is surrounded by injec tion wells, the oil production rate increased from 3.7 to 27.1 m(3)/d, while water cut decreased from 84.0% to 45.8%. Numerical simulation r esults forecast that the oil recovery will be increased by 18.1% origi nal oil in place (OOIP). Total pilot oil production as of March 1996 i s 67 500 m(3) of which 25 300 m(3), or 18.3% OOIP, is additional produ ced oil with the current oil cut of 29.7%.