Cutting wash apparatus and method

Abstract

Cutting wash apparatus includes a wash tank ( 11 ) having side walls ( 15 ) converging to an inclined lower floor (16) and containing an air agitated wash solution including a surfactant. A cyclone separator ( 27 ) receives an oil-based mud and cutting-containing slurry through inlet ( 30 ), passing mud to an outlet ( 31 ) and a cuttings-rich component to the wash tank ( 11 ). A skimmer ( 13 ) removes wash overflow and a mud and slurry fines raft floated by the agitation, and passes this to a separator ( 18 ). Separated wash liquid is aerated and returned by pump ( 19 ) to injection points ( 28, 29 ) to recycle wash and provide the agitation. An auger ( 23 ) operates in a casing ( 21 ) opening into the tank ( 11 ) and extending upward of the wash tank and having an upper end discharge outlet ( 38 ). Additional aeration and agitation air is injected through air injection bars ( 45 ).

1 . Cutting wash apparatus including:
 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 agitation;   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.   
     
     
         2 . Cutting wash apparatus according to  claim 1 , wherein the wash tank is of a hopper or hod-like configuration. 
     
     
         3 . Cutting wash apparatus according to  claim 2 , wherein the wash tank has 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. 
     
     
         4 . Cutting wash apparatus according to  claim 2 , wherein the rear of the tank has an end wall selected from a substantially vertical wall and a wall which converges with the opening into the inclined floor at its lower end to guide washed cuttings into the opening. 
     
     
         5 . Cutting wash apparatus according to  claim 1 , wherein the slurry includes an oil based mud and wherein the wash solution is a water wash containing cationic surfactants. 
     
     
         6 . Cutting wash apparatus according to  claim 1 , wherein the auger is a shaftless auger. 
     
     
         7 . Cutting wash apparatus according to  claim 6 , wherein the auger is driven from its upper end. 
     
     
         8 . Cutting wash apparatus according to  claim 1 , wherein the cyclone separator is mounted directly to the wash tank. 
     
     
         9 . Cutting wash apparatus according to  claim 8 , wherein the cyclone separator is internally screened to separate residual particulates from a mud overflow. 
     
     
         10 . Cutting wash apparatus according to  claim 8 , wherein the inlet to the cyclone separator is a tangentially directed inlet directing flow in the direction of rotation of the cyclone action. 
     
     
         11 . Cutting wash apparatus according to  claim 10 , wherein the tangential flow impinges on a curved screen whereby the entrained cuttings are screened to the cyclone underflow and the spent mud directed to the cyclone overflow. 
     
     
         12 . Cutting wash apparatus according to  claim 9 , wherein the cyclone separator is a turret fitted to the wash tank and with the internal screen is a replaceable mesh liner, whereby the inertia of the tangential flow sees the mud expelled through the mesh liner where it is collected and redirected via gravity into a mud reprocessing tank, whereupon the cuttings fall under their own weight into the wash tank. 
     
     
         13 . Cutting wash apparatus according to  claim 1 , wherein the cyclone separator receives slurry from pump apparatus including:
 a housing having an inlet for admitting to the housing a material to be pumped, and a delivery outlet connected to the inlet of said cyclone separator;   a valve on each of said inlet and said outlet;   control means adapted to selectively open and close respective said valves;   pressure reduction means under the control of said control means and adapted to reduce the pressure in said housing while said inlet valve is open to admit said material to said housing, said control means being adapted to close said inlet gate means on admission of a selected charge of said material to said housing; and   pressurizing means under the control of said control means and adapted to increase the pressure in said housing while said outlet valve is open to discharge said material from said housing to said cyclone separator.   
     
     
         14 . Cutting wash apparatus according to  claim 13 , wherein the cyclone separator is selected as to static capacity and throughput to match the discharge rate of the pump. 
     
     
         15 . Cutting wash apparatus according to  claim 1 , wherein said air agitation is provided by air injection to a bottom portion of the wash tank from a compressed air supply. 
     
     
         16 . Cutting wash apparatus according to  claim 1 , wherein the wash solution is recycled and wherein recycled wash solution and air are combined and injected along the inclined floor to provide said air agitation. 
     
     
         17 . Cutting wash apparatus according to  claim 16 , wherein the skimmer comprises an overflow system whereby floating sludge and was liquid is delivered to separator means whereby the sludge is stripped and the polished was liquid returned by pump to the wash tank. 
     
     
         18 . Cutting wash apparatus according to  claim 17 , wherein the recycled wash solution and air are combined and injected along the inclined floor to provide said agitation.