ABSTRACT
Alkaline-surfactant-polymer (ASP) flooding is a new technique that has been tested in Da Qing and Sheng Li oil fields in China in the past few years. The technique uses partially hydrolyzed polyacrylamide (HPAM) as the polymer, petroleum sulfonate (ORS-41 or TRS) as the surfactant, and sodium hydroxide (NaOH) or sodium carbonate (Na2CO3) as the alkaline component. Compared with waterflood ASP flooding may increase oil recovery efficiency by about 15 to 20%, but the use of the new technique is faced with new problems. The production fluids form stable w/o and o/w emulsions and the separation of crude oil and water becomes more difficult. It is believed that the alkali, surfactant, and polymer used in the chemical flooding causes these problems [1].
