Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
  • B03B9/00—General arrangement of separating plant, e.g. flow sheets
  • B03B9/02—General arrangement of separating plant, e.g. flow sheets specially adapted for oil-sand, oil-chalk, oil-shales, ozokerite, bitumen, or the like
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
  • E21B21/06—Arrangements for treating drilling fluids outside the borehole
  • E21B21/063—Arrangements for treating drilling fluids outside the borehole by separating components
  • E21B21/065—Separating solids from drilling fluids
  • E21B21/066—Separating solids from drilling fluids with further treatment of the solids, e.g. for disposal
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
  • E21B21/06—Arrangements for treating drilling fluids outside the borehole
  • E21B21/068—Arrangements for treating drilling fluids outside the borehole using chemical treatment
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B41/00—Equipment or details not covered by groups E21B15/00 - E21B40/00
  • E21B41/005—Waste disposal systems

Definitions

• This invention relates to the treatment of oil-contaminated drill solids, e.g. drilling muds or drill cuttings prior to reuse or disposal.
• Oil-based muds are also preferred since, in general, they permit higher drilling rates, and also they facilitate drilling at an angle to the vertical, for example, when drilling inclined well bores which may be at anything up to 50° or 60° from the vertical or more.
• the drill cuttings from such operations present a disposal problem because of the oil contamination.
• the hydrocarbon values in such oil-contaminated drill cuttings are proposed to be removed by a combination of vacuum distillation and grinding by heating the cuttings under reduced pressure in a pressure vessel equipped with means for milling or shearing the drill cuttings during the heating process.
• oil contaminated drill cuttings are passed on a conveyor belt through a preheater for partial drying and then to a high-intensity infrared heating chamber in which the volatile hydrocarbons are expelled from the cuttings at a surface temperature higher than the combustion point of petroleum.
• the oil content of oil-contaminated drill cuttings can be economically and efficiently reduced to permitted levels by washing the oil-contaminated drill cuttings, preferably after screening to remove fines and supernatant drilling mud which can be re-used, with a single solvent system consisting of a haiogenated hydrocarbon such as carbon tetrachloride or 1,1,1-trichioroethane, and centrifuging the washed cuttings to remove the oil-solvent solution, which can be recycled to the washing process and/or distilled to recover the washing solvent and an oil residue which can be recycled to the drilling process.
• a haiogenated hydrocarbon such as carbon tetrachloride or 1,1,1-trichioroethane
• the method of the invention is also applicable to the recovery of the drilling mud itself, particularly drilling muds which are weighted with barytes. Because of the cost element, the recovery of the barytes for reuse can be an important factor in the economics of subterranean and submarine drilling operations, and the present invention provides a simple efficient and economic way in which this can be done.
• the separated drilling mud can be treated in essentially the same way, for example, by initial screening or centrifuging to separate out the mud solids, and removing from the separated mud solids decontaminating oil by washing with the halohydrocarbon and centrifuging in the manner described.
• oil-contaminated drill cuttings which have been screened to remove surplus oil-based fluids and fines for re-use in the drilling operation are passed via line 1 to a mixing tank 2. If desired a portion of the separated fines may also be passed to the tank.
• the cuttings are contacted with an organic haiohydrocarbon solvent washing liquid, preferably 1,1,1-trichloroethane, fed from a storage tank 12.
• an organic haiohydrocarbon solvent washing liquid preferably 1,1,1-trichloroethane
• a recycle stream of macerated slurry is fed via line 4 from the macerator 3 to the tank 2 to maintain a desirable solids concentration in the tank.
• the main stream of macerated slurry is fed from macerator 3 via line 5 to a continuously running decanter centrifuge 6.
• Substantially oil-free cuttings are withdrawn from the centrifuge 6 via line 7 for disposal whilst separated oil/solvent washing liquid is withdrawn via line 8. This may be recycled via line 9 to the washing tank 2 whilst a slip stream is taken off via line 10 to a distillation unit II for recovery of the solvent which is returned to the solvent storage tank 12 for re-use and separation of the oil residue via line 13.
• the oil residue separated via line 13 will contain a proportion of fines and also substantial amounts of the chemical additives added to the original drilling mud and can either be collected for disposal, treated for further recovery of one or more components and/or returned to the drilling operation for use as recycle oilbased drilling mud.
• the decontaminated drill cuttings withdrawn via line 7 are in a dry, non-sticky friable powder form suitable for pneumatic transportation in a carrier gas, e.g. air stream, to a disposal point.
• a carrier gas e.g. air stream
• the decontaminated cuttings can simply be dumped overboard since oil-contamination levels of cuttings treated in accordance with the present invention is well below the minimum standards imposed by government regulations.
• the preferred embodiment of the invention at least, provides a substantially closed cycle for the recovery and reprocessing of the oil-based drilling mud, whilst at the same time substantially solving the disposal problems of the oil-contaminated drill cuttings.
• the above described method and apparatus can readily be adapted for the recovery of the mud solids themselves, e.g. the barytes used in weighied drilling muds.

Landscapes

• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Mining & Mineral Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• Physics & Mathematics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Processing Of Solid Wastes (AREA)

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• 1981
  • 1981-11-20 EP EP19810903108 patent/EP0065532A1/de not_active Withdrawn
  • 1981-11-20 AU AU78088/81A patent/AU7808881A/en not_active Abandoned
  • 1981-11-20 WO PCT/GB1981/000252 patent/WO1982001737A1/en not_active Ceased

Non-Patent Citations (1)

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