Patent Publication Number: US-11639640-B2

Title: Electro-separation cell with solids removal

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 15/562,916, filed Sep. 29, 2017, which is a national stage entry of PCT/CA2015/000196, filed Mar. 31, 2015, the disclosures of each of which are hereby incorporated by reference as if fully restated herein. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a system and method for separating oil-based drilling fluids using an electro-separation cell and more particularly to a system and method for removing sediment and other solids from an electro separation cell. 
     BACKGROUND 
     Invert emulsion drilling fluid (commonly called drilling mud) is used when drilling boreholes in the ground, such as for drilling oil or gas wells, etc. It is typically pumped through the drill string and out a nozzle on the drill bit during the drilling of the hole so that the drilling fluid can keep the drill bit cool and carry rock, clay and other solids (commonly referred to as cuttings) removed from the well by the drill bit up the annulus of the well and back to the surface. 
     Invert emulsion drilling fluids are typically water based or oil based. Oil based muds usually contain oil in the form of a petroleum product similar to diesel fuel. In addition to the oil, these oil based drilling fluids can also contain viscosifiers, weighting agents and other filtrate control additives. To remove the cuttings from the drilling fluid that has been returned to the surface, solids control equipment in the form of shakers, conveyors, centrifuges, etc. are used to remove the majority of the native clays or drill solids that make up the cuttings. 
     However, these solids control equipment are not designed to re-capture the base oils necessary to create the drilling fluids. It is the presence of hydrocarbons which are physically and chemically bound to the fines, as well as additives, that make separation and recapture through conventional means difficult. There have been attempts to re-capture the hydrocarbons in these drilling fluids using electro-separation, creating an electric field in the drilling fluids to cause the contents of the drilling fluid to separate out. However, while the hydrocarbon that separates out can be easily dealt with, since it simply rises to the top of the medium being treated, the solids and sediment separating out of the drilling fluid can cause problems with electro-separation systems. 
     SUMMARY OF THE INVENTION 
     In a first aspect, an electro-separation apparatus for separation of drilling fluids is provided. The apparatus can include: a reaction chamber; a set of parallel-spaced electrode plates provided in the reaction chamber; a sediment outlet positioned proximate a bottom of the reaction chamber to remove sediment from the reactor chamber; a plurality of wiper blades, each wiper blade positioned between a pair of adjacent electrode plates and moveable between a first position and a second position to remove sediment from the electrode plates and move the sediment towards the sediment outlet; and a power supply connected to the set of parallel-spaced electrode plates to create an electric field between the set of parallel-spaced electrode plates. 
     In a further aspect, each wiper blade in the electro-separation apparatus is moveable from the first position to the second position by the wiper blade being rotatable around an axis and the axis is positioned at a radius of curvature of the curved side wall, at a center of curvature of the curved side wall. 
     In a further aspect, the electro-separation apparatus can include: a first curved side wall; a second curved side all; a first set of parallel-spaced electrode plates provided in the reaction chamber positioned along the first curved side wall; second set of parallel spaced electrode plates provided in the reaction chamber positioned along the first curved side wall; and a plurality of wiper blades, a first set of wiper blades positioned between the electrode plates in the first set of parallel-spaced electrode plates and moveable between a first position and a second position to remove sediment from the electrode plates and move the sediment towards the sediment outlet, and a second set of wiper blades positioned between the electrode plates in the second set of parallel-spaced electrode plates and moveable between a first position and a second position to remove sediment from the electrode plates and move the sediment towards the sediment outlet. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       A preferred embodiment of the present invention is described below with reference to the accompanying drawings, in which: 
         FIG.  1    is a front perspective view of an electro-separation apparatus for separating oil-based drilling fluid; 
         FIG.  2    is a back perspective view of the electro-separation apparatus shown in  FIG.  1   ; 
         FIG.  3    is side view of an electrode plate used in the electro-separation apparatus shown in  FIG.  1   ; 
         FIG.  4    is a schematic end view of the electro-separation apparatus shown in  FIG.  1    with a wiper assembly shown in a starting position; 
         FIG.  5    is a schematic end view of the electro-separation apparatus shown in  FIG.  1    with the wiper assembly shown in a finished position; 
         FIG.  6    is a perspective view of a single wiper blade; 
         FIG.  7    is a front perspective view of an electro-separation apparatus in a second aspect; 
         FIG.  8    is a back perspective view of the electro-separation apparatus shown in  FIG.  7   ; 
         FIG.  9    is a top perspective cut-away view of the electro-separation apparatus shown in  FIG.  7   ; 
         FIG.  10    is a cut-away schematic view of the electro-separation apparatus of  FIG.  7    with a wiper assembly in a starting position; 
         FIG.  11    is a cut-away schematic view of the electro-separation apparatus of  FIG.  7    with a wiper assembly in operation; and 
         FIG.  12    is a cut-away schematic view of the electro-separation apparatus of  FIG.  7    with a wiper assembly in a finishing position. 
     
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
       FIGS.  1  and  2    illustrate an electro-separation apparatus  10  for removing hydrocarbon petroleum products from cuttings (including colloidal and ultra-fines) in oil-based drilling fluids. Electrokinetics, in conjunction with hydraulic vibration, is used to influence the movement of hydrocarbons within the drilling fluid medium. Direct current (DC) electricity provides the primary force in the form of electrokinetic phenomena. By using the electro-separation apparatus  10  to apply an electrical field to a volume of oil based drilling fluid or mud for the segregation of hydrocarbons from the drilling fluid medium and corresponding sediment (the native clays and drill cuttings), a hydrocarbon supernatant is formed that is clear of solid particles (equal to and in some cases less than 1%) while sediment settles towards the bottom of the electro-separation apparatus  10 . 
     The electro-separation apparatus  10  can include a tank forming a reaction chamber  20  and a set of parallel-spaced electrode plates  100  provided in the reaction chamber  20 . The reaction chamber  20  can form a liquid tight enclosure with two end walls  22 ,  24 , a straight side wall  32  and a curved side wall  36 . The straight side wall  32  can be provided so that it is substantially vertical while a top  38  of the curved side wall  36  can start at the top of the reaction chamber  20  and curve towards the straight side wall  32  as you move down the curved side wall  36  until the bottom end  37  of the curved side wall  36  ends proximate a bottom end  34  of the straight side wall  32 . A collection trough  40  can be provided between the bottom end  37  of the curved side wall  36  and the bottom end  34  of the straight side wall  32  so that solids and sediment that has settled out of the fluid being treated can collect in this collection trough  40 . The curved side wall  36  can curve with a substantially constant radius from a top end  38  to proximate a bottom end  37  of the curved side wall  36  where past the bottom end  37  of the curved side wall  36  the wall angles further out to start forming the collection trough  40 . 
     The length of the straight side wall  32  and the curved side wall  36  can be longer than the lengths of the end walls  22 ,  24  so that that the entire reaction chamber  20  has an elongate form. 
     The collection trough  40  can be provided at the bottom end  34  of the straight side wall  32  and at the bottom end  37  of the curved side wall  36  to collect solids and sediment that settles out of the drilling fluid being treated. The collection tough  40  can run along the length of the reaction chamber  20  from the first end wall  22  to the second end wall  24  and parallel to the straight side wall  32  and the curved side wall  36 . 
     An auger (not shown) can be provided in the collection trough  40  to move the solids and sediment that collects in the collection trough  40  towards a sediment outlet  52  in the collection trough  40  where the sediment can be removed from the collection trough  40 . In one aspect, the auger can have flighting positioned in a first direction along a first portion of the auger and flighting positioned in a second direction, opposite direction, along a second portion of the auger. The sediment outlet  52  can be provided between the first portion and the second portion of the auger. In this manner, when the auger is rotated in one direction the two different directions of the flighting in the two different portions can move solids and sediment in the collection trough  40  towards the sediment outlet  52  even though it is provided at or near the middle of the auger and the reaction chamber  20 . 
     A framework  60  can be provided to support the reaction chamber  20 . 
     A plurality of parallel-spaced electrode plates  100  can be provided inside the reaction chamber  20 . These electrode plates  100  can be formed from stainless steel, carbon steel or aluminum and can be insulated from the end walls  22 ,  24 , the straight side wall  32  and the curved side wall  36  by the use of a non-conductive liner that covers the interior surfaces of the reactor chamber  20  so that the non-conductive liner is positioned between the edges of the electrode plates  100  and the straight side wall  32  and the curved side wall  36  to prevent the electrode plates  100  from coming into electrical contact with the inside surfaces of the reaction chamber  20  and pass electrical current to the reaction chamber  20  itself. In one aspect, the non-conductive liner could be made of ultra-high-molecular-weight polyethylene (UHMWPE), fiberglass that has hydrocarbon resistant resin, etc. 
     Each of the electrode plates  100  can be a plate as shown in  FIG.  3   . In one aspect, the electrode plates  100  can have a straight side  102  to substantially conform to the straight side wall  32  of the reactor chamber  20  and an opposite curved side  106  to substantially conform to the curved side wall  36  of the reaction chamber  20 . In one aspect, the electrode plate  100  may be a flat plate. When the electrode plates  100  are positioned in the reactor chamber  20 , the electrode plates  100  can be provided parallel so that each one is parallel to the adjacent electrode plates  100  and oriented vertically in the reaction chamber  20  so that a spacing is formed between adjacent electrode plates  100  and the electrode plates  100  are positioned spaced parallel from one another running along substantially the entire length of the reaction chamber  20  from the first end wall  22  to the second end wall  24 . The straight side  102  of each electrode plate  100  will be provided adjacent to the straight side wall  32  of the reaction chamber  20  and the curved side  106  will be provided adjacent to the curved side wall  36  of the reaction chamber  20 . 
     In one aspect, the spacing between adjacent electrode plates  100  could be between 0.25 inches and 3 inches. In a further aspect, the electrode plates can be between 0.25 and 2 inches and in one aspect substantially 1.5 inches apart. In this manner, the electrode plates  100  are parallel spaced a distance between 0.25 inches and 3 inches along substantially an entire length of the reaction chamber  20 . 
     The electrode plates  100  can be connected to a voltage supply so that a voltage can be connected across adjacent electrode plates  100  to create an electric field in the drilling fluid medium being treated between adjacent electrode plates  100  in the reaction chamber  20 . Typically, the electrode plates  100  will be alternately positively and negatively charged so that electrical fields can be created between all of the electrode plates  100  in the set of electrode plates  100 . 
     A lid  80  can be provided to cover an open top of the reaction chamber  20 . The lid  80  can be provided so that a headspace is created above the electrode plates  100  and below the lid  80  in the reactor chamber  20  when the lid  80  is closed. The lid  80  and the reactor chamber  20  can form a seal so that the interior of the reactor chamber  20  is hermetically sealed when the lid  80  is closed, preventing air and other gases from entering and exiting the top of the reactor chamber  20 . A blanket of nitrogen can be provided in this headspace to prevent a buildup of oxygen in the headspace as a result of anode/cathode reactions occurring in the reaction chamber  20  and allowing the electro-separation apparatus  10  to meet a ‘Type X’ designation so that it may be used in hazardous environments. The headspace inside of the electro-separation apparatus  10  can be continuously monitored by an oxygen sensor and if the oxygen sensor determines that the level of oxygen in the headspace reaches an undesired level, more nitrogen can be routed into the headspace in order to reduce the oxygen level and eliminate a possible explosion in the headspace. 
     The pressure in the reactor chamber  20  can also be monitored in order to ensure the seal of the lid  80  and the reactor chamber  20  is not compromised. 
     Additionally, the sealing of the interior space of the reactor chamber  20  by the lid  80  allows the fluid in the reactor chamber  20  to be pressurized during operation of the electro-separation apparatus  10 . In one aspect, the nitrogen in the headspace can be pressurized so that the pressure in the reactor chamber  20  is above atmospheric pressure. In one aspect, the pressure in the reactor chamber  20  can be between 1 to 5 psi above atmospheric pressure. 
     During the processing of the batch of drilling fluid in the electro-separation apparatus  10 , the batch of drilling fluid will separate into a number of stratified layers in the reactor chamber  20 . An upper stratification layer or supernatant layer containing a high concentration of hydrocarbon will rise to the top of the reactor chamber  20  and collect on the surface of the drilling fluid. Below the upper stratification layer, a medium stratification layer will occur. This medium stratification layer will contain a low percentage of particles (fines and cuttings). Below the medium stratification layer solids and sedimentation will settle out of the fluid being treated and because of its higher density, fall towards the bottom of the reactor chamber  20 . This lower layer of solids and sediment will typically contain a highly viscous semi-consolidated invert drilling fluid mass and the majority of the fines and cuttings from the drilling fluid will form as solids and sediment in this layer. Any thickening agents, such as barite and other chemicals used in the preparation of the drilling fluid, will likely also be contained in this lower fluid mass layer. 
     The solids and sediment will settle out of the drilling fluid during its treatment and these solids and sediment will sink towards the bottom of the reactor chamber  20  and the collection trough  40  where it can be removed from the reaction chamber  20  through the sediment outlet  52 . However, some of these solids and sediment will attach to the electrode plates  100  and the curving side wall  36  before it sinks all the way to the collection trough  40 , coating the electrode plates  100  and the curving side wall  36  with solids and sediment. Theses solids and sediment can cause problems with the functioning of the electro-separation apparatus  10 . Not only will less solids and sediment potentially be removed from the reactor chamber  20  after each batch of drilling fluid has been treated because some of the solids and sediment will remain in the reaction chamber  20  clinging to the electrode plates  100  and curving side wall  36  after the reactor chamber  20  is unloaded, but additionally, coating the electrode plates  100  with this sediment can hinder the direct current power from passing through the drilling fluid in the reactor chamber  20 . To address this buildup of solids and sediment in the reaction chamber  20 , a wiper assembly  200  can be used that in conjunction with the curved side wall  36  will move solids and sediment that has collected on the curved side wall  36  and the electrode plates  100  towards the collection trough  40 . The shape of the reaction chamber  20  is designed for solids and sediment collection at the base of the reaction chamber  20  in the collection trough  40 . 
       FIGS.  4  and  5    show the wiper assembly  200  in more detail. The wiper assembly  200  can have a number of wiper blades  210  with each wiper blade  210  attached to an axle  220  with the axle  200  forming an axis around which the wiper blade  210  is rotatable. The axle  220  can be positioned near the top of the straight side wall  32  so that the wiper blades  210  extend from the axle  220  towards the curved side wall  36 . The axle  200  can be positioned at a radius of curvature of the curved side wall  36 , at a center of curvature of the curved side wall  36 , so that the axle  220  is positioned at a center of curvature of the curved side wall  36 . 
       FIG.  6    illustrates a single wiper blade  210 . Each wiper blade  210  can be made of a non-metallic material and have a tip  212  and a proximal end  216  with the proximal end  216  attached to the axle  220 . Each wiper blade  210  can also have a length running from the center of the axis formed by the axle  220  to the tip  212  of the wiper blade  210  that is substantially the length of the radius of curvature between the curved side wall  36  and the axle  220  leaving just a gap between the tip  212  and the curved side wall  36 . The curvature of the curving side wall  36  can be constant along all or a lot of its length and the length of the wiper blades  210  between its tip  212  and the center of axis formed by the axle  220  the wiper blade  210  is attached to can be substantially the radius of curvature of the curved side wall  36  with a gap between the tip  212  and the curved side wall  36  so that a tip  212  of the wiper blade  210  can follow along the curvature of the curved side walls  36  as the wiper blade  210  is rotated around the axis formed by the axle  220  while a substantially constant gap is maintained between the tip  212  and the curved side wall  36 . Each wiper blade  210  can have a width that is substantially the same as the spacing between adjacent electrode plates  100  so that edges of the wiper blade  210  can sweep across the inner surfaces of the adjacent electrode plates  100 . 
     Referring again to  FIGS.  4  and  5   , one or more hydraulic cylinders  230  can be used to rotate the axle  220  and thereby rotate the wiper blades  210  around the axle  220 . The hydraulic cylinders  230  can be attached to the axle  220  by a plate  235 . As the wiper blades  210  are rotated by the axle  220  around their proximal ends  216  and an axis formed by the axle  220 , the wiper blades  210  will rotate downwards between the electrode plates  100  and the tips  212  of the wiper blades  210  will move down along a curve corresponding to the curve on an inside surface of the curving side walls  36 . The edges  214  of each wiper blade  210  can also scrape the electrode plates  100  as the wiper blade  210  is rotated by the axle  220 , removing sediment that has built up on the electrode plates  100 . 
       FIG.  4    illustrates the wiper assembly  200  in the starting or first position with the wiper blades  210  positioned above or near a top of the electrode plates  100  and the tips  212  of the wiper blades  210  at or above the top end  38  of the curving side walls  36  with the wiper blade  210  positioned extending substantially horizontally. The shape of the reaction chamber  20  lends itself to effectively sweep the solids and sediment, as well as the colloids, to the lowest point of the reaction chamber  20 , which will be the collection trough  40 , for removal of the sediment from the reaction chamber  20 . The shape of the reaction chamber  20  effectively represents the centripetal movement of the solids by the wiper blades  210 . 
     In operation, the axle  220  is rotated which causes the wiper blades  210  to rotate around the axis formed by the axle  220  causing the wiper blades  210  to sweep downwards between the electrode plates  100  with the edges  214  of the wiper blades  210  removing sediment that has built upon the electrode plates  100  and the tips  212  of the wiper blades  210  scraping off sediment from the inside surface of the curving side walls  36 . 
       FIG.  5    illustrates the wiper assembly  210  in a finished or second position where the wiper blades  210  are positioned at or adjacent to the straight side wall  32  with the edges  214  and the tips  212  of the wiper blades  210  having scraped sediment off the electrode plates  100  and the surface of the curving side wall  36  and downwards into the collection trough  40 . In the second position, the wiper blade  210  can be positioned substantially vertically. After the wiper assembly  200  has swept the wiper blades  210  to this finishing position, the wiper blades  210  can be rotated back up to the starting position shown in  FIG.  4    to be used again to scrape sediment from the reactor chamber  20 . 
     One or more hydraulic vibrators (not shown) can be provided in physical contact with the reactor chamber  20  so that the vibrators can be used to vibrate the reactor chamber  20  and the drilling fluid therein in an attempt to loosen sediment that has collected on the electrode plates  100 , end walls  22 ,  24 , straight side wall  32  and curved side wall  36 . 
     During operation of the electro-separation apparatus  10 , hydrocarbons will separate from the drilling mud. Unlike the sediment, the hydrocarbons will rise to the top of the reaction chamber  20  where this top layer of accumulated hydrocarbons can be removed through a liquid outlet  90  after the drilling fluid has been treated in the electro-separation apparatus  10 . The liquid outlet  90  can be one or more apertures provided passing through the straight side wall  32  and starting proximate a top end of the straight side wall  32  so that the hydrocarbon that has collected on top of the medium in the reactor chamber  20  can be drained off separately from the underlying liquid. 
     In one aspect, the liquid outlet  90  can be used in conjunction with a skimmer  300  to remove the top layer of accumulated hydrocarbons from the reactor chamber  20  after the drilling fluid has been treated in the electro-separation apparatus  10 . The skimmer  300  can include a clear well that is in fluid communication with the reactor chamber  20  by the liquid outlet  90  and runs the depth of the straight side wall  32  the skimmer  300  is installed on. Liquid from the reactor tank  20  can enter the clear well through the liquid outlet  90 . Inside the skimmer  300 , a vertical telescoping tube can be provided in the clear well. The telescoping tube can be raised so that a top of the telescoping tube is above the surface of the drilling fluid being treated and then lowered below the surface of the treating fluid so that treated fluid will enter the telescoping tube and be routed away. The top of the telescoping tube can be lowered down to the level where a person wants to drain the top layer out of the reactor chamber and all the fluid above the top of the telescoping tube will drain into the open top of the telescoping tube and out of the reactor chamber  20 . 
     In one aspect, the telescoping of the telescoping tube could be electronically controlled. An electronic specific gravity reader could read the specific gravity of the treated drilling fluid in the reactor chamber and the depth where a targeted specific gravity of the drilling fluid is determined (identifying where a upper layer of hydrocarbon supernatant ends) could be used to lower the top of the telescoping tube to this identified depth, causing this upper layer of fluid to drain out of the reactor chamber  20  and then leaving behind the denser, less desirable fluid. 
     In operation, a batch of drilling fluid can be introduced into the reaction chamber  20  when the wiper assembly  200  is in the starting position shown in  FIG.  4    so that the drilling fluid fills the reaction chamber  20  between the electrode plates  100 . An electric field can then be generated between the electrode plates  100  to subject the batch of drilling fluid in the reaction chamber  20  to an electro-separation stage. A DC voltage can be applied across the electrode plates  100  to create an electric field between the electrode plates  100  that passes through the batch of drilling fluid in the reaction chamber  20 . Typically, as the hydrocarbons, solids and sediment separate in the drilling fluid, the voltage can be decreased or increased to keep the amperage constant. As the solids and sediment settle out, the current can more easily pass through these condensed solids and sediment that are forming near the bottom of the housing. 
     The electric field applied between the electrode plates  100  can cause the separation of the drilling fluid in the batch through the use of the process of electrokinetics to destabilize the bonds between the hydrocarbon, the fines and other cuttings and the drilling fluid. Electrokinetics involves the processes of; electrophoresis, dielectrophoresis, electromigration and electroosmosis. Electrophoresis is the primary phenomenon which occurs in the drilling fluid. Electrophoresis involves the movement of charged particles through a fluid medium under the influence of an electrical field. This process acts to reduce ultra-fine colloidal particles in the drilling fluid. Dielectrophoresis involves the movement of uncharged particles under a non-uniform electrical field. This is dependent on the fluid medium, particle properties, particle size and gradient of the voltage field. Electromigration involves the movement of ions towards the electrodes of opposite charge. The electric field destabilizes the emulsion, allowing hydrocarbons to be released. Electroosmosis involves the movement of water from anode (+) to cathode (−). Applied DC current breaks any bonds that water may have with other particles and allows it to migrate within the drilling fluid. 
     During this electro-separation stage, the electric field can be maintained for a period of time, allowing the electrokinetic effect to act on the drilling fluid and the hydrocarbon to separate from the solids and the sediment (the fines and cuttings). In one aspect, this could be a few hours or more, however, the amount of time will vary on the conditions of the drilling fluid, size of the reactor chamber  20 , number of electrode plates  100 , etc. As the electric field continues to be passed through the drilling fluid, hydrocarbon segregated from the solids and sediment, rise to the surface of the drilling fluid and solids and sediment will continue to settle out towards the bottom of the reaction chamber  20 , some of which will settle on the curving side wall  36  and the surfaces of the electrode plates  100 . 
     The wiper assembly  200  can be used to remove sediment from the surfaces of the electrode plates  100  that has been deposited there during the electro-separation stage. Referring to  FIG.  4   , the wiper assembly  200  will begin with the wiper blades  210  in the starting or first position, with the wiper blades  210  positioned above or near a top of the electrode plates  100  and the tips  212  of the wiper blades  210  positioned at or near the top of the curving side wall  36  extending substantially horizontally. The hydraulic cylinders  230  can then rotate the axle  220  so that the wiper blades  210  are rotated and sweep downwards between the electrode plates  100  with the edges  214  scraping sediment of the electrode plates  100  while the tips  212  of the wiper blades  210  run down and along the curving side wall  36 . This sweep of the wiper blades  210  will continue, moving sediment that has collected on the electrode plates  100  between the electrode plates  100  and the curving side walls  36  downwards and towards the collection trough  40  where the sediment will eventually be removed from the reaction chamber  20  through the sediment outlet  52 . Eventually, the sweep of the wiper blades  210  will end at the finishing position shown in  FIG.  5   . 
     The wiper apparatus  200  can be used at the end of the treatment cycle to remove the sediment (as well as colloids and water) from the reaction chamber  20  through the collection trough  40  after the high quality base/synthetic oil has been removed from the reaction chamber  20  by the skimmer  300 . The wiper apparatus  200  can move this sediment (and colloids and water) into the collection trough  40  where it will be augured towards the sediment outlet  52  and removed from the reaction chamber  20  through the sediment outlet  52  to allow a new batch of drilling fluid to be loaded into the reaction chamber  20  for treatment. In one aspect, the wiper assembly  200  can repeat this action several times prior to the next batch of drilling fluid being loaded in order to effectively remove any residual solids and sediment that may not have been recovered on the first sweep, second sweep, etc. of the reaction chamber  20 . 
     Additionally, the wiper apparatus  200  can also be used to sweep the reaction chamber  20  before the end of the treatment of the drilling fluid and before the hydrocarbon is removed from the reaction chamber  20 . This can be done to move sediment that has collected on the surfaces of the electrode plates  100  and the inside surface of the curving side wall  36  towards the collection trough  40  during the treatment of the drilling fluid and prevent too much sediment from building up on these surfaces or to simply move the sediment towards the collection trough  40  in preparing for it to be removed when the treatment of the drilling fluid in the reaction chamber  20  is complete. 
     The vibrators can be also be used to vibrate the reaction chamber  20  to try and cause sediment that has collected on the electrode plates  100 , the end walls  22 ,  24 , the straight side wall  32  or the curved side wall to be shaken off or even to be loosened enough to be scraped off by the wiper blades  210 . By vibrating the reaction chamber  20  not only can this exacerbate the fluid medium into a highly vibratory state in order to release and free fluid that is trapped throughout the medium, but it also can cause sediment or other solids that have collected along the electrode plates  100  because of high surface tension to vibrate loose and fall off the electrode plates  100  or even just loosened to make the wiper blades  310  more effective at scraping it off. The vibrators can be used at the same time as the sweeping assembly  200  to both vibrate off the sediment and scrape it off with the wiper blades  210  or at different times, such as before the sweeping apparatus  200  is used to try and loosen the sediment from the electrode plates  100  before the wiper blades  210  sweep along the electrode plates  100 . 
     In some aspects, the pressure in the reaction chamber  20  can be increased above atmospheric pressure to aid in the separation of the drilling fluid. 
       FIGS.  7 - 9    illustrate an electro-separation apparatus  500  in a further aspect. The electro-separation apparatus  500 . The electro-separation apparatus  500  can include a tank forming a reaction chamber  520 . A first set  100 A of parallel-spaced electrode plates  100  can be provided running along a first side of the reaction chamber  520  and a second set  100 B of parallel-spaced electrode plates  100  can be provided running along a second side of the reaction chamber  520  so that the first set  100 A of parallel-spaced electrode plates  100  and the second set  1008  of parallel-spaced electrode places  100  run parallel to each other. 
     The reaction chamber  520  can form a liquid tight enclosure with two end walls  522 ,  524 , a two curved side walls  532 ,  536 . The curved side walls  532 ,  536  can start at the top of the reaction chamber  520  and curve towards a middle of the reaction chamber  520  as you move down the curved side walls  532 ,  536  and curve towards a collection trough  540  provided in a bottom of the reaction chamber  520  near or at a middle of the reaction chamber  520 . The collection trough  540  can run along a bottom of the reaction chamber  520  between and perpendicular to the ends walls  522 ,  524  with the curved side walls  532 ,  536  running parallel to the collection rough  540 . 
     In this manner, solids and sediment that settle out of drilling mud being treated in the reaction chamber  520  can be directed by the curvature of the curved side walls  532 ,  536  towards the collection trough  540 . 
     The length of the curved side walls  532 ,  536  can be shorter than the lengths of the end walls  522 ,  524  so that that the entire reaction chamber  20  has a shortened form. 
     The first set  100 A of electrode plates  100  can extend along and adjacent to the first curved side wall  32  and the second set  1008  of electrode plates  100  can extend along and adjacent to the second curved side wall  536 . 
     An auger (not shown) can be provided in the collection trough  540  to move the solids and sediment that collects in the collection trough  540  towards a sediment outlet  552  in the collection trough  540  where the sediment can be removed from the collection trough  540 . 
     A liquid outlet  590  can be provided in the reactor chamber  520  to remove hydrocarbon from near a top of the reactor chamber  520  and liquid that has collected in the reactor chamber  520  after the electro-separation apparatus  500  has separated a batch of drilling fluid. The liquid outlet  590  can be provided in the end wall  524  and positioned above a bottom of the reactor chamber  520  and the sediment outlet  552  so that hydrocarbon and then liquid can be drained from the reactor chamber  520  from points positioned above where the lower layer of solids, sediment and colloids (and some water) will form on the bottom of the reactor chamber  520  before being removed through the sediment outlet  522 . 
     A framework  560  can be provided to support the reaction chamber  520 . 
     The electrode plates  100  can be formed from stainless steel, carbon steel or aluminum. Each of the electrode plates  100  can be a plate as shown in  FIG.  3   . In one aspect, the electrode plates  100  can have a straight side  102  and an opposite curved side  106  to substantially conform to the curved side wall  532  or the curved side wall  536  of the reaction chamber  520 . In one aspect, the electrode plate  100  may be a flat plate. When the electrode plates  100  are positioned in the reactor chamber  520  in the first set of parallel-spaced electrode plates  100  or the second set of parallel-spaced electrode plates  100 , the electrode plates  100  can be provided parallel so that each one is parallel to the adjacent electrode plates  100  and oriented vertically in the reaction chamber  520  with a spacing formed between adjacent electrode plates  100 . The electrode plates  100  are positioned spaced parallel from one another running along substantially the entire length of the reaction chamber  520  from the first end wall  522  to the second end wall  524  in both the first set of parallel-spaced electrode plates  100  and the second set of parallel-spaced electrode plates  100 . The curved side  106  of the electrode plate  100  can be positioned against either the first curved side wall  532  or the second curved side wall  536  depending on if the electrode plate  100  is positioned in the first set  100 A of electrode plates  100  or the second set  100 B of electrode plates  100 . The straight side  102  can be positioned facing inwards of the reaction chamber  520 . 
     A lid  580  can be provided to cover an open top of the reaction chamber  520 . 
     During the processing of the batch of drilling fluid in the electro-separation apparatus  500 , synthetic/base oil will segregate from the drilling fluid medium, rise to the surface of the medium and allow for solids and sediment to settle out and sink towards the bottom of the reactor chamber  520  and towards the collection trough  540 . Eventually the solids and sediment that have collected in the collection trough  540  where it can be removed from the reaction chamber  520  through the sediment outlet  552  after the hydrocarbons and the liquids are removed through a liquid outlet. However, some of these solids and sediment will attach to the electrode plates  100  and the curving side walls  532 ,  536  and will require additional means before it can be discharged by way of the collection trough  540 . 
     A wiper assembly  600  can be used that in conjunction with the curved side walls  532 ,  536  will move solids and sediment that has collected on the curved side walls  532 ,  536  and the electrode plates  100  in the first set  100 A of electrode plates  100  and the second set  1008  of electrode plates  100  towards the collection trough  540 . 
     The wiper assembly  600  can have a number of wiper blades  610  provided between adjacent electrode plates  100  so that the wiper blades  610  can remove solids and sediment that have collected on the surfaces of the electrode plates  100  and the curved side walls  532 ,  536 . A first set of wiper blades  610  can be provided attached to a first axle  622  with the wiper blades  610  passing between electrode plates  100  in the first set  100 A of electrode plates  100 . A second set of wiper blades  610  can be provided attached to a second axle  624  with the wiper blades  610  in this second set of wiper blades  610  passing between electrode plates  100  in the second set  1008  of electrode plates  100 . The first axle  622  can be provided at a radius of curvature of the first curved side wall  532  and the second axle  624  can be provided at a radius of curvature of the second curved side wall  536 . 
     Each wiper blade  610  can have a tip  612  and a proximal end  616 . The proximal end  616  of the wiper blade  610  can be attached to either the first axle  622  or the second axle  624  so that the wiper blade  610  extends between adjacent electrode plates  100  to the tip  612  of the wiper blade  610  with the tip  612  of the wiper blade  610  being positioned adjacent either the first curved side wall  532  or the second curved side wall  536 . Each wiper blade  610  can have a length that is substantially the length between the curved side wall  532  and the first axle  622  if the wiper blade  610  is provided between electrode plates  100  in the first set of electrode plates  100  or the length between the curved side wall  536  and the second axle  624  if the wiper blade is provided between electrode plates  100  in the second set of electrode plates  100 . Each wiper blade  610  can have a width that is substantially the same as the spacing between the adjacent electrode plates  100  the wiper blade  610  is positioned between. 
     One or more hydraulic cylinders  630  can be used to rotate the first axle  622  and thereby rotate the wiper blades  610  attached to the first axle  622  and positioned between electrode plates  100  in the first set  100 A of electrode plates  100  around the first axle  622 . As these wiper blades  610  are rotated by the first axle  622  around their proximal ends  616 , the wiper blades  610  will rotate downwards between the electrode plates  100  in the first set  100 A of electrode plates  100  and the tips  612  of the wiper blades  610  will move down adjacent to the inside surface of the first curving side walls  532 . 
     In a similar manner, one or more hydraulic cylinders  632  can be used to rotate the second axle  624  and thereby rotate the wiper blades  610  attached to the second axle  624  and positioned between electrode plates  100  in the second set  1008  of electrode plates  100  around the second axle  624 . As these wiper blades  610  are rotated by the second axle  624  around their proximal ends  616 , the wiper blades  610  will rotate downwards between the electrode plates  100  in the second set  100 B of electrode plates  100  and the tips  612  of the wiper blades  610  will move down adjacent to the inside surface of the second curving side walls  534 . 
       FIG.  10    illustrates the wiper assembly in a starting position with the wiper blades  610  positioned above or near a top of the electrode plates  100  in the first set  100 A of electrode plates  100  and the second set  100 B of electrode plates  100  and the wiper blades  610  positioned substantially horizontally. The tips  612  of the wiper blades can be positioned at or above the top ends of the curving side walls  532 ,  536 . The shape of the reaction chamber  520  lends itself to effectively sweep the solids and sediment using the sweeping assembly  600  to the lowest point of the reaction chamber  520 , which will be the collection trough  540  provided running along the bottom and middle of the reaction chamber  520 . With the solids and sediment collected in the collection trough  540 , the solids and sediment can be removed from the reaction chamber  520  after the treatment of the drilling fluid has been completed. 
     In operation, the first axle  622  and the second axle  624  are rotated which causes the wiper blades  610  between both the first set  100 A and the second set  1008  of electrode plates  100  to rotate around their proximal ends  216  causing the wiper blades  210  to sweep downwards between the electrode plates  100  with the edges of the wiper blades  610  removing sediment that has built upon the electrode plates  100  and the tips  612  of the wiper blades  610  scraping off sediment from the inside surface of the curving side walls  532 ,  536 . 
     The wiper blades  610  between the first set  100 A of electrodes  100  can be operated in unison with the wiper blades  610  between the second set  100 B of electrodes  100  or independently, such as by alternating the sweeping of the first set  100 A of electrode plates  100  and then the second set  1008  of electrode plates  100  or vice versa. 
       FIG.  11    shows the wiper blades  610  as they are sweeping downwards. The wiper blades  610  between the first set  100 A of electrode plates  100  and the wiper blades  610  between the second set  100 B of electrode plates  100  will rotate towards each other until they reach a second position or finished position, as shown in  FIG.  12   , with the wiper blades  610  between the first set of electrode plates  100  and the wiper blades  610  between the second set of electrode plates  100  being positioned vertically and substantially parallel to one another. The collection trough  540  can be provided directly below the spacing formed between the parallel positioned wiper blades  610 . 
     In operation, a batch of drilling fluid can be introduced into the reaction chamber  520  when the wiper assembly  600  is in the starting position shown in  FIG.  10    so that the drilling fluid fills the reaction chamber  520  between the electrode plates  100 . An electric field can then be generated between the electrode plates  100  to subject the batch of drilling fluid in the reaction chamber  520  to an electro-separation stage. A DC voltage can be applied across the electrode plates  100  to create an electric field between the electrode plates  100  that passes through the batch of drilling fluid in the reaction chamber  520 . As the electric field continues to be passed through the drilling fluid, hydrocarbon from the drilling fluid will rise to the surface of the drilling fluid medium and solids and sediment will settle out towards the bottom of the reaction chamber  520 , some of which will adhere to the surfaces of the electrode plates  100  and collect on the curving side walls  532 ,  534 . 
     After some time has passed, the wiper assembly  600  can be used to remove sediment from the surfaces of the electrode plates  100  and the inner surface of the curving side walls  532 ,  536  that has been deposited there during the electro-separation stage. The wiper assembly  600  can be moved from its first position to its second position to scrape and sweep solids and sediment that have collected on the electrode plates  100  and the curving side walls  532 ,  536  towards the collection trough  540 . 
     The sweeping motion of the wiper blades  610  downwards between the starting position shown in  FIG.  10    to the finishing position shown in  FIG.  12    can scrape off solids and sediment that have accumulated on the surfaces of the electrode plates  100  and the curved side walls  532 ,  536  and move the solids and sediment downwards along the curved side walls  532 ,  536  towards the collection trough  540 . After the wiper assembly  600  has swept the wiper blades  610  to the finishing position, the wiper blades  610  can be rotated back up to the starting position shown in  FIG.  10    to be used again to aid in removing sediment from the reactor chamber  520 . 
     After the hydrocarbon and other liquids have been removed from the reaction chamber  520 , the sediment (and colloids and water) in the collection trough  540  can be removed through the sediment outlet  552  to allow a new batch of drilling fluid to be loaded into the reaction chamber  520  for treatment. 
     After the hydrocarbon and other liquids have been removed from the reaction chamber  520  out of the liquid outlet  590 , the sediment (and colloids and water) in the collection trough  540  can be removed through the sediment outlet  552  to allow a new batch of drilling fluid to be loaded into the reaction chamber  520  for treatment. 
     The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.