Alkaline-surfactant-polymer Flood – From the Laboratory to the Field

摘要

Recent years have seen renewed focus on chemical Enhances Oil Recovery. Techniques such as polymer flooding, surfactant flooding or alkali-surfactant-polymer flooding are under evaluation globally for the application in maturing oil fields. Despite extensive chemical EOR study and laboratory work carried out in the 1980’s, field piloting is still considered vital for a quantitative assessment of the technical and economic risks involved in a large-scale chemical EOR implementation. Current industry experience in chemical EOR operations is largely dominated by polymer floods in China as well as, more recently, the polymer flood in Marmul by Petroleum Development Oman (PDO). For surfactant-polymer and alkali- surfactant-polymer (ASP), only multi-well pilots and small fields operations have been carried out to date. Having identified significant target oil volumes for ASP flooding, PDO and Shell have recently embarked on a program to mature ASP technology. Following initial screening and laboratory work, a series of single-well chemical tracer tests has been carried out in three fields. This project successfully demonstrated the ability of the selected ASP formulations to locally reduce the remaining oil saturation in the reservoir significantly below the water-flood residual saturation. Based on this encouraging achievement, PDO and Shell are currently working toward an ASP pattern-flood pilot designed to quantify the technical and economic feasibility of full-field ASP injection. The paper discusses the workflow which was followed from identifying a target reservoir, the selection of an ASP formulation, the design, operation and evaluation of the single-well chemical tracer tests and, finally, the design of the pattern-flood pilot.