This paper presents an overview of the continuing development of low-tension surfactant and micellar (or microemulsion) flooding. Current technology is considered from the standpoint of DOE and other projects undertaken in industry. Commercial application and projects undertaken in industry. Commercial application and economics also are considered. Introduction Surfactant flooding is one enhanced oil recovery (EOR) method being developed to increase the U.S. energy supply. Other methods include thermal techniques, CO, flooding, polymer flooding, and the use of caustic solutions. Micellar systems are injected to improve displacement efficiency in the reservoir. These solutions have been shown to reduce residual oil saturations in the laboratory and field far below those values obtained with a waterflood. Polymer solutions are injected next to propagate the expensive micellar system efficiently propagate the expensive micellar system efficiently through the reservoir. The polymer solutions improve the over-all reservoir conformance by providing mobility control. Finally, water is injected after the polymer solution.Surfactant use to improve oil recovery began in the late 1920's and early 1930's. Essentially, two different concepts have developed for using surfactants. One concept uses a large pore volume of a low-concentration surfactant solution. The use of low-concentration surfactant solutions has led to low-tension waterflood processes. The second concept uses a small pore volume of a processes. The second concept uses a small pore volume of a high-concentration surfactant dispersion. Dispersions containing high-surfactant concentration sometimes are called micellar solutions. Certain subclasses are referred to as microemulsions, swollen micelles, fine emulsions, or soluble oils. The use of small pore volumes of highly concentrated surfactant dispersions has led to a miscible-type recovery process known as Maraflood, TM a soluble oil recovery process known as Uniflood, TM and other patented processes. patented processes. This paper presents an overview of the continuing development of low-tension surfactant flooding and micellar, or microemulsion, flooding. Current technology is considered from the standpoint of DOE and other projects undertaken in industry. Some recent projects projects undertaken in industry. Some recent projects have shown an expanding technology. Based on the number of new tests, field activity is continuing at a high level. This paper also discusses commercial application in terms of lead time and expenditures. The potential for commercial application is considered in view of the Lewin and Assocs., Inc., National Petroleum Council (NPC), and Office of Technology Assessment (OTA) reports. Improvements needed for further technological development are presented. Timing for large-scale applications is reviewed in terms of supply and demand and competition from other liquid hydrocarbon fuels. Specific economic cases based on Marathon Oil Co.'s experience in Illinois are compared using 1975 and 1978 costs. High-Surfactant vs Low-Surfactant Projects Three sources were assumed to represent the current status of surfactant or micellar methods. Table 1 shows micellar/polymer field projects funded, either in part or entirely, by DOE. Other projects listed in the NPC report that began after 1973 are shown in Table 2. These tests are funded entirely by industry. Projects given in Tables 1 and 2 do not represent a complete list. JPT P. 1089