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U.S. Department of Energy
Office of Scientific and Technical Information

Asphalt plug emplacement process

Patent ·
OSTI ID:6750729
A process is described for plugging a permeable earth formation by injecting into it an oil-in-water emulsion in which asphalt is dissolved or suspended in the oil-phase and the emulsifier is, at least predominately, a cationic surfactant. The composition and concentration of the asphalt-containing oil-phase and the cationic emulsifier are arranged so that, in the emulsion, the suspended particles (droplets and/or solids) are sufficiently small and well dispersed to flow through the pores of the earth formation to be treated, the pH is relatively near neutral, and the emulsion breaks when the pH is increased. A pH-increasing reactant is dissolved in the aqueous phase of the emulsion, and its composition and concentration are correlated with the properties and location of the earth formation to be treated so that the pH of the emulsion is increased to one at which the emulsion breaks after the emulsion has been placed in the formation to be treated. (6 claims)
Assignee:
Shell Oil Co.
Patent Number(s):
US 3901316
OSTI ID:
6750729
Country of Publication:
United States
Language:
English