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Mobilization of residual oil under equilibrium and nonequilibrium conditions

Journal Article · · SPEJ, Soc. Pet. Eng. J.; (United States)
DOI:https://doi.org/10.2118/10198-PA· OSTI ID:5359937

A microvisual study of residual oil mobilization that uses a relatively simple chemical system consisting of water, n-propanol, and cyclohexane is presented. Two different classes of experiments were performed to determine the sensitivity of the capillary number required to displace a particular residual oil globule from chemical equilibrium. It was found that under certain circumstances the capillary number required to mobilize the oil drop could be reduced greatly if the displacing phase contained more alcohol than it would in equilibrium with the trapped phase. Experiments clearly demonstrated that spontaneous emulsification by a diffusion and stranding mechanism could not account for the differences between equilibrium and nonequilibrium capillary numbers. Experimental observations did correlate well with the development of interfacial turbulence (Marangoni effect). Variations that, according to theory, tended to enhance the level of interfacial turbulence between the equilibrium and nonequilibrium capillary numbers were observed. The importance of the Marangoni effect relative to laboratory oil recovery experiments is discussed. A second class of experiments consisted of observing the displacement of residual oil globules that had been increased in volume (swollen) by mass transfer from a continuous phase flowing too slowly to displace the drop. Once the residual oil globule attained equilibrium with the continuous phase, the flooding velocity was increased until the swollen globule was displaced.

Research Organization:
Univ. of Texas
OSTI ID:
5359937
Journal Information:
SPEJ, Soc. Pet. Eng. J.; (United States), Journal Name: SPEJ, Soc. Pet. Eng. J.; (United States) Vol. 23:5; ISSN SSPJD
Country of Publication:
United States
Language:
English