Treatment of subsurface oil-bearing formations with oil-wetting cationic emulsions
A treatment by an oil-wetting cationic oil-in-water emulsion increases the permeability of an oil reservoir to waterflooding, using fresh water or brine. The emulsion is composed of an oil-soluble relatively polar surfactant, a water-soluble organic cationic surfactant, oil, and water. A water-soluble nonionic surfactant and inert salts may also be added. Amino nitrogen-containing compounds are oil-soluble surfactants. The water-soluble surfactants are quaternary ammonium compounds. Commercial sources are Redicote E11 (cationic) and Redicote E12 (nonionic). Alkali metal and/or alkaline earth metal halide, sulfate, phosphate, or carbonate salts are added to the emulsion to reduce water swelling and disintegration tendencies of clay in the reservoir. At least 1.5 percent of salt should be present in an emulsion used in clayey reservoirs. Berea and Ohio sandstone cores containing brine and residual oil were treated by the emulsion, then flooded with water which permitted an additional oil recovery of 22 percent over a brine flood (about 60 percent).
- Assignee:
- Shell Oil Co.
- Patent Number(s):
- US 3422890
- OSTI ID:
- 7301154
- Country of Publication:
- United States
- Language:
- English
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