Design of alkaline/surfactant/polymer enhanced oil recovery scheme for a Saudi Arabian limestone reservoir
[Thesis]
V. O. Eme
King Fahd University of Petroleum and Minerals (Saudi Arabia)
1994
186
M.S.
King Fahd University of Petroleum and Minerals (Saudi Arabia)
1994
Over 50% of the original oil in place is left behind after primary and secondary recovery. Alkali-surfactant-polymer (ASP) flooding process has been found to be capable of recovering some of the oil left behind after primary and secondary recovery. The polymer increases the macroscopic displacement efficiency. The alkali and surfacant lower the interfacial tension (IFT) which results in higher microscopic displacement efficiency. An alkaline-surfactant-polymer enhanced oil recovery (EOR) scheme was proposed for Saudi Arabian limestone reservoirs. The interaction between the reservoir brine, alkali, surfactant and polymer was investigated. The slug was formulated with a mixture of sodium bicarbonate and sodium carbonate. B1083 anionic surfactant was chosen for the slug because it was thermally stable at the studied reservoir temperature of 90C. A water-in-oil emulsion was formed in the B1083 surfactant/crude oil system. The presence of alkali and surfactant led to a decrease in the viscosity of the polymer (Flocon 4800C) solution. The addition of alkali to the surfactant solution did not result in any further decrease in the IFT of the surfactant/crude oil system. The adsorption of surfactant in the presence of alkali was lower than that without alkali. However, the percent reduction in adsorption decreases with increasing surfactant concentration. A new relationship for calculating the shear rate in porous media was developed.