摘要 |
An environmentally acceptable water-in-oil microemulsion composition includes at least one emulsifying surfactant, at least one biodegradable hydrocarbon solvent, at least one co-solvent, at least one hydrocarbon co-surfactant, and water. The microemulsion composition may be used in a method for rendering fluids from oil external to water external. The microemulsion composition may be combined with water or a water based fluid to produce a spacer fluid utilized in removing oil and oil-residues from a surface, particularly that of wellbores in the drilling of oil and gas wells.
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