Appraisal Of Micellar Flooding, Carbon Dioxide And Surfactant Flooding Projects

Abstract

Abstract Results of selected carbon dioxide, micellar and surfactant flooding field tests are analyzed. In the case of micellar flooding, factor analysis was employed to identify the most significant parameters. Of the three processes, miscible carbon parameters. Of the three processes, miscible carbon dioxide and micellar flooding show the promise of significantly increasing the domestic oil production and the crude oil reserves at the current production and the crude oil reserves at the current state-of-the-art. Applicability of these processes to the Penn Grade oil reservoirs is also examined. The surfactant flooding process still suffers-from a drawback in the sensitiveness of the aqueous surfactant solutions currently being used to mono-and divalent ions present in the reservoir. Although carbonated waterfloods have been successful in laboratory studies, the few reported field test statistics indicate that it is not particularly attractive, possibly in view of the extended project life necessitated by the injection of many pore volumes. The process may have application in 'Viscous oil reservoirs, where a nonthermal recovery technique is contemplated. While the micellar flooding process is expected to yield oil recoveries of 40–55%, it has been tested in low salinity environments. The factor analysis and regression studies conducted in this work were of a qualitative nature, and the observations made are limited by the unknown reservoir characteristics and flooding conditions. Factors such as reservoir heterogeneities, post waterflood oil saturation, and the mobility buffer (polymer solution) volume are important in the design of current micellar floods, using small micellar slugs in reservoirs with rather low salinity formation water and low divalent ion environments. Miscible carbon dioxide process has been successfully tested in the laboratory. Several large field projects are currently underway. The only completed field test indicates that about two barrels of oil were recovered per reservoir barrel of carbon dioxide left in the formation. Of the three processes considered here a micellar flood offers favorable economics, applied to low porosity, low permeability Penn Grade oilfields, with residual waterflood oil saturations of 35–40%. Introduction With increasing oil and gas consumption in the U.S., declining reserves (32.68 billion bbls of oil as of Jan. 1, 1976), and increasing imports, there is evergrowing interest in enhanced oil recovery. Many publications on this subject reflect the impetus and endeavors in this direction. A significant example is the report by Lewin and Associates, Inc. Considering the vast amount of oil left in the U.S. oil reservoirs (298 billion bbls), rather optimistic predictions were made for the tertiary oil production potential - on the order of one million B/D by 1985. Lately, however, it has become clear that such a rate may not be achieved even by 1990; the reserves have been scaled down accordingly. The underlying pessimism is attributable to exorbitant operational costs, very large initial investments needed, as well as a lack of large scale field tests of certain promising processes in many Oil-producing areas. In some instances, the field results have been less than encouraging. This paper reviews and analyzes two of the four processes, which appear to hold the most promise for processes, which appear to hold the most promise for the future, viz. micellar and carbon dioxide flooding. A third, surfactant flooding, is also covered in view of its relationship to micellar flooding. (The other two processes, steam injection and in situ combustion, and to a smaller extent, polymer flooding, are not considered in this paper). Carbon dioxide flooding is discussed first, followed by micellar and surfactant flooding. In each case, field results are tabulated and analyzed Factor and regression analyses are used in the case of micellar flooding. Finally, applicability of these processes to Penn Grade oil fields is briefly examined.