Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
  • B09C—RECLAMATION OF CONTAMINATED SOIL
  • B09C1/00—Reclamation of contaminated soil
  • B09C1/02—Extraction using liquids, e.g. washing, leaching, flotation
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
  • B01D21/24—Feed or discharge mechanisms for settling tanks
  • B01D21/2433—Discharge mechanisms for floating particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
  • B01D21/24—Feed or discharge mechanisms for settling tanks
  • B01D21/245—Discharge mechanisms for the sediments
  • B01D21/2461—Positive-displacement pumps; Screw feeders; Trough conveyors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
  • B01D21/26—Separation of sediment aided by centrifugal force or centripetal force
  • B01D21/267—Separation of sediment aided by centrifugal force or centripetal force by using a cyclone
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
  • B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
  • B04C9/00—Combinations with other devices, e.g. fans, expansion chambers, diffusors, water locks
  • B04C2009/004—Combinations with other devices, e.g. fans, expansion chambers, diffusors, water locks with internal filters, in the cyclone chamber or in the vortex finder
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
  • B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
  • B04C9/00—Combinations with other devices, e.g. fans, expansion chambers, diffusors, water locks

Definitions

• This invention relates to a cuttings wash apparatus and method.
• This invention has particular but not exclusive application to a cuttings wash apparatus and method for use on drilling rigs permitting proper disposal and/or recycling of spent drilling mud compositions, and for illustrative purposes reference will be made to such application. However, it is to be understood that this invention could be used in other applications, such as entrained particulates washes generally generally.
• a wash tank having side walls at least the lower portions of which converge to an inclined lower floor and containing an air agitated wash solution including a surfactant;
• a cyclone separator adapted to receive an oil-based mud and cutting- containing slurry and passing a particulates-rich separated component of said slurry to said wash tank;
• a skimmer operable to remove a raft formed at the surface of the wash solution including emulsified oil based mud and slurry fines floated by said agitating; an auger casing below said inclined floor and opening into said tank at a lower portion of the floor, the auger casing extending upward of a top of the wash tank and having an discharge outlet toward its upper end; and
• an auger located in the auger casing and extending from the opening into said inclined floor to said discharge outlet.
• the wash tank may be of a hopper or hod-like configuration.
• the wash tank may have a generally rectangular upper portion having a pair of side walls that converge downward and are closed together by the inclined floor forming both front and lower closure for the tank.
• the rear of the tank may have an end wall which is substantially vertical or which converges with the opening into the inclined floor at its lower end to guide washed cuttings into the opening.
• the wash solution will be selected according to the nature of the continuous phase entraining the drill cuttings.
• OBM oil based muds
• the mud residue requires the use of a water wash containing surfactants to clean the bulk of the mud residue from the cuttings.
• the water wash may be made up with a surfactant composition selected from cationic surfactants selected to wet oily clay particles.
• the water wash may be selected to work in salt water.
• injection/surfactant combination may be selected in order to promote froth flotation of especially clay minerals cleaned from the drill cuttings.
• the auger may be a shaftless auger.
• the auger is preferably driven from its upper end.
• the cyclone separator may be mounted directly to the wash tank or its supporting structure in order that it may discharge separated cuttings directly into the wash tank.
• the cyclone separator may be internally screened to separate residual particulates from the mud overflow. This mud is directed directly back to mud tanks for re-blending and re use.
• the inlet to the cyclone separator may be a tangentially directed inlet directing flow in the direction of rotation of the cyclone action. The tangential flow may impinge on a curved screen whereby the entrained cuttings are screened to the cyclone underflow and the spent mud directed to the cyclone overflow.
• the cyclone separator may be in the form of a simple turret fitted to the wash tank and screened internally with a replaceable mesh liner.
• the cuttings and mud may enter tangentially and the inertia sees the mud expelled through the mesh liner where it is collected and redirected via gravity into a mud reprocessing tank. With inertia spent, the cuttings may fall under their own weight into the wash tank.
• the screen plays a minor part during normal operation but comes to play a significant role when drilling trips or a shaker screen breaks and the system has to cope with a large inflow of mud relative to the cuttings load.
• the cyclone separator may be selected to match the particular charge characteristics of the slurry delivery system.
• the slurry delivery system may involve the use of a slurry pump such as that described in WO 2006/037186.
• the pump may consist of a pressure vessel, an inlet nozzle, and an ejector nozzle by which vacuum and pressure are applied, and an outlet nozzle, in this case connected via a discharge line connected to the inlet of the cyclone separator line.
• the inlet and outlet nozzles are selectively closed by interconnected knife gate valves, operated in tandem by a pneumatic cylinder whereby when one valve is closed, the other is open, and vice-versa.
• An ejector valve located in the ejector nozzle alternately creates vacuum and generate air flow through the vessel. The air from the ejector may be introduced into the discharge line after closure of the outlet valve, if the discharge line requires the boost.
• Drilling mud entraining cuttings may be captured by the pump via either a gravity feed from a hopper or alternatively under vacuum.
• the pump may deliver the slurry in a pump-and-fill cycle.
• the cyclone separator is preferably selected as to static capacity and throughput to match the discharge rate of the pump.
• the throughput of the cyclone be in the region of 24 tonnes per hour.
• Cuttings in the wash tank pass under gravity along the inclined floor and into the path of the auger through the lower opening.
• the cuttings are exposed to agitation which enhances the wash effect.
• the air agitation may be provided by air injection a bottom portion of the wash tank from a compressed air supply.
• the wash solution may be recycled and the recycled wash solution and air combined and injected along the inclined floor to provide the agitation.
• Air bubbles from the agitation entrains emulsified oil based mud and other pollutants to form a raft at the surface of the wash solution to be removed by a skimmer.
• the skimmer may comprise an overflow system whereby floating sludge and wash liquid is delivered to separator means whereby the sludge may be stripped and the polished wash liquid returned by pump to the wash tank.
• the overflow may pass into a tank across a stripper belt trapping sludge on top of the belt and allowing the polished wash liquid to pass through the belt.
• the belt may be a one-pass disposable web or a strippable recirculating web.
• the recycled wash solution may again be entrained with air and injected along the inclined floor to provide the agitation.
• Drag through losses of the wash liquid to either the sludge removal or auger delivery of washed cuttings may be made up by any suitable means. For example, making up may be done in the sludge separator or the wash tank
• Washed cuttings may be slowly transported up the auger. This dewaters the cuttings allowing solution to drain back into the main body of the tank.
• the cuttings may be delivered from the auger outlet either directly or indirectly to a dryer assembly.
• the dryer may receive cuttings as a uniform continuous feed at a controlled rate because the cyclone and wash actions smooth out the pulsed delivery from the preferred pump.
• the dryer's operational performance band is preferably honed allowing optimum performance to be achieved and maintained throughout the entire operation.
• Cuttings may now be discharged from the dryer and depending on
• FIG. 1 is a side view of apparatus in accordance with the present invention.
• FIG. 2 is a front view of the general arrangement of a pump for use with the apparatus of FIG. 1 ;
• FIG. 3 is a side view of the pump of FIG. 2.
• a cuttings wash apparatus including a supporting, crane hoistable frame 10 supporting a wash tank 1 1 and auger 12 assembly.
• the top of the tank 1 1 is provided with an overflow skimmer assembly 13.
• a pump assembly 14 Remote from the supporting frame 10 there is provided a pump assembly 14 as illustrated in Figs. 3 and 4.
• the wash tank 1 1 has a pair of opposed side walls 15 that converge to meet an inclined floor portion 16 which forms both front and bottom wall of the tank 1 1 .
• An inclined rear wall 17 closes the back of the tank. The cuttings settle passing across the inclined floor portion 16 to a lower opening 20.
• the lower opening 20 admits the cuttings to an auger housing 21 mounted beneath the floor portion 16 and extending to an upper portion 22 above the level of the tank 1 1 top.
• the auger housing 21 contains an auger 23 which is driven from its upper end by a motor and gearbox assembly 24.
• the wash liquor 25 includes a cationic surfactant/flotation agent which causes the oil component of OBM to float as a raft 26 with other contaminants to be skimmed off by the overflow skimmer assembly 13.
• the surfactant composition of this example is capable of use in salt water and comprises 220 ppm Wildcat Concentrate (Wildcat Chemicals Australia Pty Ltd) of notional composition:
• a wash recycle tank 18 takes wash liquid and sludge from the overflow skimmer 13 and separates the sludge to waste, entrains air and pumps the polished wash liquid via pump 19 to the tank 1 1 .
• Part of the recycled liquid is returned via upper port 28 to cuttings passing into the tank and part is directed through lower port 29 to a pair of spaced, longitudinal agitator bars 44 each having a plurality of approximately 1 .0mm agitator holes. Wash liquid and entrained air projected from the agitator holes agitates the cuttings passing down the tank floor 6 to provide agitation, wash enhancement and flotation raft formation. Further agitation and froth flotation action is provided by air injection through port 39 to a pair of spaced, longitudinal injection bars 45 each having a plurality of approximately 0.2mm air injection holes.
• a cyclone separator 27 comprises a cylindrical turret having a tangential slurry inlet 30 through which slurry passes from the slurry pump 14 to impinge on a curved screen, allowing cuttings to drop into the tank 1 1 while the mud passes centrifugally about the turret to a mud exit 31 to reclamation and blending.
• the slurry inlet 30 is connected to the outlet 32 of the pump assembly 14 via a flexible hose (not shown).
• the pump comprises a steel vessel 34 having a tapered lower body 35 to the outlet 32 which has a knifegate valve closure 28.
• the vessel has an inlet 36 controlled by an inlet knifegate valve 37 operated in concert with the outlet knifegate valve 28 to effect cycling of the pump.
• An ejector assembly 40 includes a compressed air supply 41 feeding an internal venturi which is selectively valved whereby it depresses the housing via conduit 42 when the inlet knifegate 37 is open and the outlet knifegate valve 28 is closed to charge the vessel 34 and pressurizes the vessel when the inlet knifegate 37 is closed and the outlet knifegate valve 28 is open to discharge the vessel into the slurry inlet 30.
• the pump assembly has a pallet frame assembly 43 and may be moved by forklift.
• Washed cuttings are slowly transported up the auger 23 which dewaters the cuttings allowing solution to drain back into the main body of the tank 1 1 .
• the cuttings are then delivered directly into a dryer assembly (not shown) via gravity outlet 38 which now receives a uniform continuous feed at a controlled rate.
• the dryer's operational performance band has been honed allowing optimum
• Cuttings are now discharged from the dryer assembly 13 and depending on environmental constraints can be returned to the ocean floor or alternatively transported back to shore for further processing.
• the main objectives of this system are:

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Mining & Mineral Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Geology (AREA)
• Fluid Mechanics (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Soil Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Cyclones (AREA)
• Treatment Of Sludge (AREA)
• Auxiliary Devices For Machine Tools (AREA)

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Publications (2)

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• 2010
  • 2010-11-27 EP EP10832425.2A patent/EP2506977A4/de not_active Withdrawn
  • 2010-11-27 US US13/512,853 patent/US20120318583A1/en not_active Abandoned
  • 2010-11-27 CN CN2010800541286A patent/CN102791379A/zh active Pending
  • 2010-11-27 WO PCT/AU2010/001589 patent/WO2011063463A1/en not_active Ceased
  • 2010-11-27 AU AU2010324537A patent/AU2010324537B2/en not_active Ceased

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