Separation of oils from solids
AssigneeUnion Oil Company of California
InventorDonald C. Van Slyke
Life of this patent
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Abstract
Drill cuttings are cleaned of oil-based drilling mud and oil using a cleaning agent, such as a C6-C10 carboxylic acid, that is preferentially oil soluble at one pH and preferentially water soluble at another pH. The oily cuttings are treated with the carboxylic acid and then washed with an aqueous, alkaline washing solution, which converts the carboxylic acid to its water soluble salt and, with vigorous agitation, lifts most of the oil from the cuttings. In other embodiments, the process is used for cleaning oil-contaminated soil, sand, and gravel, and for separating the oils from the solids in oily sludges.
Claims21
A method for cleaning oil-contaminated particulate solids, which comprises:
- contacting contaminated solids with a non-aqueous liquid composition comprising a carboxylic acid;
- then contacting the solids with an aqueous wash containing a reagent for converting said carboxylic acid to a water-soluble carboxylate salt;
- and
- removing an aqueous phase containing carboxylate salt and entrained oil.
A method for cleaning drill cuttings contaminated with oil-based drilling mud in a well drilling operation, which comprises:
- (a) contacting cuttings with a non-aqueous, liquid composition comprising a carboxylic acid, the composition having substantial solvency for oils and the cuttings being contaminated with oil-based drilling mud comprising suspended, particulate solids selected from the group consisting of clays and weighting materials;
- (b) washing the cuttings with an aqueous wash comprising a base for converting the carboxylic acid to a water-soluble carboxylate salt;
- (c) separating from washed cuttings an aqueous phase containing dissolved carboxylate salt and entrained drilling mud comprising said suspended, particulate solids;
- and
- (d) separating from the aqueous phase drilling mud still comprising said suspended, particulate solids.
Dependencies are inferred from the claim text.