Commercial ASP Flood Test in Daqing Oil Field

Abstract Alkali-Surfactant-Polymer (ASP) pilot test with small well spacing and the test with enlarged well spacing for commercial ASP flood are successful in Daqing Oil Field, demonstrating ASP process can greatly enhance oil recovery and bring more economic benefits. However, there are also some problems appearing during ASP flood test, such as serious scale, produced fluids hard to be disposed, and with the well spacing enlarged these two disadvantages might be worse. Therefore, a commercial ASP field test is performed to study performances of ASP flood, scaling characteristics and processing techniques of produced fluids. The five-spot well pattern is adopted in test area, including 18 injection wells and 29 producing wells, and chemical agent, sodium alkylbenzene sulfonate, is produced by Daqing Oil Field. On the basis of laboratory core flood, the formula has been optimized, which can create ultra-low interfacial tension with wide ranges and favorable emulsification. The studies, laboratory core test and numerical simulation, show that ASP system can improve oil recovery 20% more than water injection. At present, polymer injection is following the ASP flood, and the performances from commercial ASP flood are different from those of previous ASP flood. When water cut is slight declined, the injectivity will be greatly increased; the scale is serious for ground equipment, but it is rarely found in the borehole. With the surfactant produced, oil and water separation of produced fluid becomes much harder. The oil recovery enhanced by commercial ASP flood is less than ASP pilot test. If the well spacing is shortened, surfactant performance further improved and ASP system is more optimized, oil recovery efficiency will be further enhanced.