Micellar flooding and ASP - Chemical methods for enhanced oil recovery

Chemical flooding methods hold particular attraction for recovering the "re sidual oil" left in the reservoir after waterflooding. This paper describes and compares the results for two promising methods, viz. micellar flooding and alkaline-surfactant-polymer (ASP) flooding processes. Both of these me thods have been tested successfully in the field. notably micellar flooding . Laboratory results are described for micellar floods in consolidated sandst one cores as well as in unconsolidated sand packs, including a three-dimens ional model, equipped with horizontal or vertical wells. Floods were also c arried out in unconsolidated cores using combinations of an alkali, surfact ant and a polymer. Individual slugs were injected sequentially in some of t he experimental while the three components were mixed and injected as a sin gle slug in other experiments. Oil recoveries in the two cases were similar . Results for the two processes are compared and contrasted, showing that, on the basis of oil volume recovered per unit mass of the chemical used, the two processes are similar, with micellar flooding having an edge. However, on the basis of total oil recovery, micellar flooding is the superior proce ss, with oil recoveries ranging from 50 to 80% of the oil left in the porou s medium after a waterflood. Practical implications of the results are disc ussed.