Micellar-Polymer Screening Criteria And Design

Abstract

Abstract The field application of Micellar-Polymer flooding is a complex and expensive operation. It is, therefore, imperative that the design of the process for a specific application be thoroughly studied as regards both the physical parameters affecting the fluid design and the interaction of this fluid system with the reservoir characteristics and properties. In addition, advantage should be taken of the reservoir properties in designing the flood pattern properties in designing the flood pattern configurations. Factors discussed include such parameters as reservoir and fluid properties, pilot test methods, quality control, and micellar-polymer process costs and requirements. There are many depleted oil fields that could produce tremendous amounts of tertiary oil by micellar-polymer flooding if the rate of return were adequate; however, even at the present free market price, many of these fields would not produce an price, many of these fields would not produce an adequate rate of return. Tertiary micellar-polymer flooding would be more than competitive with synfuels from coal and shale if the same price incentives discussed for synfuels would be applied to tertiary oil recovery. Introduction Micellar-polymer flooding is one of the most technically sophisticated of the Enhanced Oil Recovery (EOR) technologies by which some of the 300 billion barrels of so-called unrecoverable oil becomes a target. Because of its technical sophistication, it becomes imperative that prospects for application of the process are thoroughly evaluated from both a technical process are thoroughly evaluated from both a technical and economic viewpoint. Estimates of potential EOR reserves have ranged from as low as 11 billion barrels to as high as 115 billion barrels. The most recent estimate narrows the range to between a low of 11 billion barrels and a high of 42 billion barrels, depending on a range of $13.75 to $22.00 per barrel for the oil. An increase of recovery efficiency of 1 percent would add 4 billion barrels of oil to present reserves. An increase of 4 percent, or about 16 billion barrels, would be equivalent to all oil expected to be produced from the Gulf of Mexico and Prudhoe Bay together. Thus the stakes involved are very high. Most of these technically sophisticated processes are front-loaded financially; this is particularly true for micellar-polymer flooding and, for this reason, a thorough knowledge of the reservoir and the applicability of the process is essential. Reservoir rock and fluid properties determine the mechanism and the effectiveness by which a specific EOR process displaces the reservoir oil and water from the formation. In addition economic consideration must indicate an adequate return on the investment. Oil recovery, price of crude, cost of chemicals, and well and price of crude, cost of chemicals, and well and equipment costs are important in making these evaluations. The technical viability of micellar-polymer flooding depends on two major factors:the micellar slug should have a high unit displacement efficiency andthe system design should result in a high volumetric sweep efficiency. However, there are many factors which determine the efficacy of the micellar slug and the volumetric sweep efficiency. It is the purpose of this paper to consider some of the factors purpose of this paper to consider some of the factors that enter into the consideration of establishing high unit displacement efficiency and volumetric efficiency as well as economic considerations. Because industry experience to date in micellar-polymer flooding has been overwhelmingly limited to sandstone reservoirs, comments will be limited to this type of reservoir. RESERVOIR AND FLUID PROPERTIES AFFECTING MICELLAR-POLYMER FLOODING In analyzing the applicability of micellar-polymer flooding to a given reservoir, the importance of having a complete understanding of the reservoir and fluid characteristics cannot be overemphasized. Such characteristics as the nature of the oil and water content, relative permeability, mobility ratios, formation fractures and variations in permeability, porosity and formation continuity can have a dramatic porosity and formation continuity can have a dramatic effect on the success or failure of the process. Each reservoir must be analyzed in light of its own properties and characteristics. properties and characteristics.