摘要 |
The middle phase emulsion of a crude oil emulsion produced by a surfactant flooding of an oil reservoir is demulsified by contacting it with a water-soluble alkali metal hydroxide in an amount and under conditions sufficient to cause the hydrolysis of the middle phase emulsion and its subsequent separation into phases, wherein one of the phases is primarily an oil phase. The oil phase is then separated and, thereafter, can be further demulsified by demetalizing the oil by contacting it with a carboxylic acid or an amine salt of a carboxylic acid. It may be desirable to concurrently or subsequently treat the oil with an organic base, which can also be an amine demulsifier, to obtain a pH of from about 7 to about 9 in the final oil phase recovered from the acid demetalization step.
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