Apparatus and method for removing and recovering oil and/or other oil-based drilling mud additives from drill cuttings

A process for cleaning oil-based drilling mud from drill cuttings prior to environmentally acceptable disposal of the cuttings, which comprises:

• a. collecting drill cuttings which are contaminated with drilling mud;
• b. mixing the collected, contaminated drill cuttings with a solvent for the drilling mud to dissolve the drilling mud and to form a slurry containing the cuttings, which solvent has a low latent heat of vaporization between 50 and 250 BTU/pound and is liquid at ambient temperature and pressure, is substantially miscible with oil and substantially immiscible with water and vaporizes at a temperature below about 180.degree. F.;
• c. separating drill cuttings from the slurry to provide cuttings which are sufficiently free of oily contamination for environmentally acceptable disposal;
• d. heating the solvent which contains drilling mud by heat transfer with waste heat normally available at the drilling site to vaporize the solvent from the drilling mud;
• e. recovering the drilling mud for recycle to the drilling mud available for drilling;
• and
• f. condensing the vaporized solvent for recycle in the process by heat transfer with environmentally available fluid at ambient temperatures.

A process for cleaning and separating organic liquids from contact with inorganic solids in order to prepare the inorganic solids for environmentally safe disposal and recover the organic liquids, comprising the steps of:

• a. immersing the inorganic solids covered with organic liquids in a bath of solvent and subjecting said immersed inorganic solids covered with organic liquids to turbulent conditions in order to at least partially remove the organic liquids from the surface of the inorganic solids and produce a slurry of partially cleaned inorganic solids and solvent;
• b. subjecting the partially cleaned inorganic solids to a countercurrent flow of solvent to remove any remaining organic liquids from contact with the inorganic solids such that the inorganic solids are substantially free of organic liquids;
• c. recovering the inorganic solids for disposal under environmentally acceptable conditions;
• and
• d. subjecting the remaining mixture of solvent and dissolved organic liquids to heat in order to separate the solvent by vaporization from the organic liquids and recycling the solvent for reuse in the process.

Apparatus for cleaning oil-based drilling mud from drill cuttings in order to prepare the cuttings for environmentally acceptable disposal, comprising:

• a. means for collecting drill cuttings which are contaminated with drilling mud;
• b. means for contacting the contaminated drill cuttings with a solvent which is liquid at ambient temperature and pressure, substantially miscible with oil, and substantially immiscible with water, and having a boiling point between about 100.degree. F. and about 180.degree. F., to dissolve drilling mud in the solvent, to provide drill cuttings which are sufficiently free of oily contamination for environmentally acceptable disposal and leaving drilling mud-laden solvents;
• c. means for transporting the environmentally acceptable drill cuttings to the environment;
• d. means for heating the drilling mud-laden solvent with engine coolant to vaporize the solvent from the drilling muds;
• e. means for recovering the drilling mud for further handling;
• and
• f. means for condensing the vaporized solvent for recycling in the process by heat transfer with environmentally available fluid at ambient temperatures.