Open AccessSurfactant-enhanced alkaline flooding for light oil recovery. Quarterly report, July 1--September 30, 1995
Author(s) -
D. T. Wasan
Publication year - 1995
Language(s) - English
Resource type - Reports
DOI - 10.2172/161511
Subject(s) - porous medium , pulmonary surfactant , emulsion , enhanced oil recovery , dielectric , materials science , petroleum engineering , oil field , perpendicular , surface tension , porosity , oil in place , chemical engineering , microwave , composite material , computer science , chemistry , geology , physics , thermodynamics , optoelectronics , petroleum , mathematics , engineering , geometry , organic chemistry , telecommunications
The overall objective of this project is to develop a very cost-effective method for formulating a successful surfactant-enhanced alkaline flood by appropriately choosing mixed alkalis which form inexpensive buffers to obtain the desired pH (between 8.5 and 12.0) for ultimate spontaneous emulsification and ultra-low tension. In addition, the novel concept of pH gradient design to optimize flood water conditions will be tested. The problem of characterizing emulsions in porous media is very important in enhanced oil recovery applications. This is usually accomplished by externally added or in situ generated surfactants that sweep the oil out of the reservoir. Emulsification of the trapped oil is one of the mechanisms of recovery. The ability to detect emulsions in the porous medium is therefore crucial to designing profitable flood systems. The capability of microwave dielectric techniques to detect emulsions in porous medium is demonstrated by mathematical modeling and by experiments. This quarter the shape dependence of the complex dielectric properties of W/O and O/W type dispersions in the microwave frequency region were analyzed using the generalized effective medium theory of Hanai. The computations show that the authors earlier finding for spherical dispersions can now be extended to include nonspherical geometries. The computed results show that the difference in dielectric behavior of the two emulsion types are a strong function of the shape of the dispersions, with the differences vanishing when the two phases are oriented as layers parallel and perpendicular to the electromagnetic field