Enhanced oil recovery by CO/sub 2/ foam flooding. First annual report
An extensive review of the literature revealed that the use of foam to lower the mobility of gases used to displace oil has been considered since 1956. Although early work was related mainly to light hydrocarbons, it is natural to extend the concept to the CO/sub 2/ flooding process. Samples of foaming agents, compatible with oil reservoir environments, were obtained from major manufacturers. Ninety-three samples were tested both alone and in admixture. The most promising class of additives appears to be ionic surfactants produced by ethoxylation of a linear alcohol followed by sulfation. One of the best, Plurafoam NO-2N was tested in a linear sandpack and found to reduce the mobility of gas relative to water an average of 300-fold. Viscosity measurements of the foam at varying shear rates were made to help explain the dramatic change in gas mobility in the linear flow model. The foam is non-Newtonian but many-fold more viscous than the liquid from which it is generated at all reasonable shear rates. Viscosities exceeding 1000 centipose are routinely obtained. Addition of water-soluble polymers to the foaming liquid greatly enhances the stability of the foam. Five different polymer structures were tested, all of which had a common cellulosic type backbone. Of this group, hydroxypropyl cellulose and zanthan gum appear to be the most promising candidates. The superiority of these polymers lies primarily in their stability at reservoir conditions in the acid environment created when carbon dioxide dissolves in water.
- Research Organization:
- New Mexico State Univ., Las Cruces (USA). Dept. of Chemical Engineering
- DOE Contract Number:
- AC21-78MC03259
- OSTI ID:
- 5494648
- Report Number(s):
- DOE/MC/03259-6
- Country of Publication:
- United States
- Language:
- English
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