Published 12 issues per year
ISSN Print: 1091-028X
ISSN Online: 1934-0508
Indexed in
The Importance of Capillary Forces in Waterflooding: An Examination of the Buckley-Leverett Frontal Displacement Theory
ABSTRACT
In the study described in this article waterflood saturation profiles have been simulated at field injection rates, using the complete fractional flow equation, in models of length ranging from 1 m to 200 m. The profiles change from very gradual in the 1 m model to near piston-like in the 200 m model. It has been demonstrated that neglecting the capillary term from the complete fractional flow equation results in a multiple-valued saturation profile. The simulated profiles indicated that the Buckley-Leverett front is never reached at reservoir oil-water interfacial tensions. Only at very low interfacial tensions does the capillary term become vanishingly small. The behavior observed in waterfloods, according to which the saturation profile becomes steeper at increasing water injection rates, is explained in terms of a capillary model in which there is pressure equilibration between the parallel capillaries of the model. It is shown that, at reservoir interfacial tensions, in this model the water front in the narrower capillary is ahead of the front in the wider capillary and also that the distance between the two fronts decreases at increasing water injection rates, but the front in the wider capillary never advances ahead of the front in the narrower capillary. This capillary model is shown to lead to the complete fractional flow equation of Leverett.
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Li Sheng, Dong Mingzhe, Luo Peng, A crossflow model for an interacting capillary bundle: Development and application for waterflooding in tight oil reservoirs, Chemical Engineering Science, 164, 2017. Crossref
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Rezaei N.. , Firoozabadi A.. , Pressure Evolution and Production Performance of Waterflooding in n-Heptane-Saturated Fired Berea Cores, SPE Journal, 19, 04, 2014. Crossref