Abstract
Studying zones, geological sediments, oil and water, etc. of different characteristics, suitable ASP systems mainly with alkylbenzene sulfonate, bio-surfactant, NaOH, Na2CO3 and polymer were screened. After getting good results in laboratory studies, five ASP pilot tests have been conducted with different well spacings, zones and at different locations etc. Our aim was to study: 1) the injectivity and productivity of ASP systems; 2) the damage to the reservoir with different kinds of alkaline; 3) the method of lift and how to increase very low productivity; 4) Chromatographic separation with different well spacing; 5) the effect of this EOR method and its potential; 6) its technical and economical benefits.
Both laboratory and pilots studies showed that different zones, oil and water, and different surfactant components all require different ASP systems; bio-surfactant is compatible with alkylbenzene sulfonate; and no matter what kind of alkaline where selected in the pilot, theoretically, there is some damage to the zone, but the damage to the reservoir was not significant in the pilots, the same for chromatographic separation. Numerical simulation and pilot results both showed that more than 20% OOIP oil recovery were obtained over that of water flooding. The actual production data was better than numerical simulation. Even in a reservoir with long-term 100% water cut, the chemical cost per ton of incremental oil is around 30$ to 40$. Especially in a very low oil price situation in the world today, this method can obtain good benefits both technically and economically.
Over all, the success of these ASP flooding pilots in Daqing Oil Field are good examples on enhanced oil recovery with similar types of reservoir sediment as Daqing, and also provides a new method to achieve sustained development of resource developing companies.
