Patent Abstract:
An oil-water separator for use in a trench, which surrounds an oilfield. The separator is positioned in the ground such that an inlet conduit extends at about the same level as the bottom of the trench. The trench water is admitted into the housing, where it contacts a plurality of buoyant oil-absorbing members, causing the oil particles to adhere to the surface of the oil-absorbing members. An outlet conduit located downstream from the oil-absorbing members is connectable to a pump to cause the oil-free water to be pumped from the housing and diverted away from the trench.

Full Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to oilfield equipment, and more particularly to an apparatus for separating water and oil that can be use in-situ. 
     Conventionally, an oil well is encompassed with a water-retaining moat, or ditch designed to rain water washed away from the area surrounding the drilling or production rig. The ditch is formed about the periphery of a zone defined by the governmental regulations for the protection of the environment. When small amounts of oil escape from the well bore or are spilled by trucks, the rain water tends to carry the oil droplets, along with the rain water into the ditch, wherein the oil-water mixture is retained. A levee is constructed on the outer edge of the ditch to prevent the water from the ditch escaping outside of the defined zone. 
     Despite all efforts, heavy rains and sometimes flood waters fill the ditch to capacity and cause the water mixed with the suspended oil to flow over the levee, thereby contaminating the surrounding area. From time to time, the ditch is inspected to make sure that the level of liquids in the trench has not exceeded the allowable value. A part of the ditch is made intentionally at a lower level to created the so-called sump. Even the best inspections may miss a critical increase in the liquid level within the sump, which may quickly fill to capacity and overflow if not carefully monitored. From time to time, the water with suspended oil particles is pumped out and transported away from the site to a de-contamination facility, where the oil may be recovered. Naturally, such transportation increases the cost of the oilfield operation. 
     The present invention contemplates provision of an oil-water separator that can be installed in the trench surrounding the oil well to capture oil and prevent it from being carried over the levee by rising water. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide an in situ apparatus for separating oil from water that can be installed in an oilfield ditch. 
     It is another object of the present invention to provide an oil-water separator that has oil-absorbing means for retaining a quantity of oil within the apparatus, thereby preventing escape of the oil and contamination of the surrounding areas. 
     These and other objects of the present invention are achieved through a provision of an oil-water separator that is adapted for positioning in the ground next to the trench surrounding an oilfield. A portion of the separator housing is buried below the trench bottom, while the inlet conduit is positioned at about the same level as the trench bottom. 
     A plurality of buoyant oil-absorbing members are positioned in the housing; the trench water with oil particles suspended therein is admitted through the inlet conduit. The oil particles contact the oil-absorbing members and adhere thereto. An outlet conduit is positioned downstream from the oil-absorbing members. The outlet conduit is connectable to a pump to allow removal of the oil-free trench water from the housing. A diverting pipe coupled to the outlet of the pump diverts the water away from the housing and the trench. The water can be diverted over the levee surrounding the trench or to other desired location. As a result the oil is removed from the trench water, and the level of liquid in the trench is controlled. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference will now be made to the drawings, wherein like parts are designated by like numerals and wherein 
         FIG. 1  is a perspective view of the oil-water separator in accordance with the present invention. 
         FIG. 2  is a perspective view of the oil-water separator apparatus in accordance with the present invention transported to or from the job site. 
         FIG. 3  is a schematic view of the separator apparatus in accordance with the present invention positioned in the trench adjacent an oilfield, with the ditch not having any water. 
         FIG. 4  is a schematic view similar to  FIG. 3 , with the ditch half full of water. 
         FIG. 5  is a schematic view similar to  FIGS. 3 and 4 , with the ditch being full of water. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning now to the drawings in more detail, numeral  10  designates the oil-water separator apparatus in accordance with the present invention. As can be seen in the drawings, the separator  10  comprises a separator housing  12  having a closed bottom  14 , vertical front wall  16 , back wall  20 , a pair of side walls  18  and  22 , and an open top  24 . The walls  16 ,  18 ,  20 , and  22  and the bottom  14  define an interior hollow chamber of the housing  12 . The side wall  22  is provided with an inlet conduit  26  extending outwardly in a transverse relationship to the vertical wall  22 . The inlet conduit  26  has an inlet opening  28  for admitting liquid into the separator housing  12 . 
     An opening  30  is formed in the upper part of the wall  22 , and the conduit  26  is positioned therein. The inlet conduit  26  communicates with an interior chamber of the housing  12  through the opening  30 . A water-permeable mesh screen  32  is positioned in the opening  30  to prevent floating debris, such as sticks, leaves, and other such undesirable objects from entering the interior chamber of the housing  12 . 
     A vertical dividing plate  40  is positioned inside the housing  12 , dividing the interior chamber of the housing into two distinct portions, an inlet portion  42  and an outlet portion  44 . The dividing plate  40  is secured and extends from a top edge  46  of the front wall  16  and the back wall  20 . The vertical dimensions of the dividing plate  40  are smaller than the height of the vertical walls  16  and  20 , such that a channel  48  is formed below a lower edge  50  of the separating plate  40 . The horizontal dimensions of the plate  40  are slightly smaller or equal to the distance between the front wall  16  and the back wall  20 . 
     A slot  52  is formed in the plate  40  at a level approximately co-planar with the bottom of the inlet conduit  26 . An inner water permeable mesh screen  54  is inserted through the slot  52  to extend substantially across the width of the housing  12 , from the side wall  18  to the side wall  22 . An outlet conduit  56  is positioned in the outlet portion  44  of the interior chamber to allow removal of liquid from the interior of the housing  12 . The outlet conduit  56  has an outlet opening  58 . The conduit  56  is operationally connected to a pump  60  to facilitate removal of the liquid form the housing  12 . The open top  24  of the housing  12  is protected by a pair of hinged covers  62  and  64  which are secured to extension plates  66 ,  68 , which are mounted on the upper edge of the walls  16  and  20 . The securing plates  66  and  68  extend vertically outwardly from the edge  46 , allowing pivotal movement of the covers  62  and  64 . A cutout  70  is formed in the cover  64  to accommodate extension of the outlet conduit  56  from the chamber portion  44  outside of the housing  12 . The bottom, inlet end  72  of the outlet conduit  56  rests on the screen  54 , as can be seen in  FIG. 1 . 
     The present invention provides for the use of a plurality of oil absorbing members  80 , which are positioned in the chamber portion  42  above the screen  54 . The absorbent members  80  are formed from porous material suitable for attracting and retaining as much oil particles as possible. The absorbent members  80 , which can be two or more in number, are buoyant; they float close to the surface of the liquid inside the chamber portion  42 , as will be described in more detail hereinafter. 
     Turning now to  FIGS. 3–5 , the oil-water separator  10  in accordance with the present invention is seen positioned in an oilfield adjacent an oil well  82 . A ditch, or trench,  84  surrounds the oil well  82 . The separator  10  is partially buried in the soil wherein a hole  86  has been formed. Most of the separator housing  12  is below the ground level  83 . The hole  86  is immediately adjacent to the ditch  84 , preferably close to the lowest, sump area of the ditch  84 . The inlet conduit  26  is positioned close to the bottom  88  of the ditch  84  so as to receive water through the opening  28 . 
     A certain quantity of water is initially deposited into the housing  12 , with the level of preloaded water  90  reaching about the level of the mesh screen  54 . The absorbent members  80  rest on the screen  54 , initially above the water level  90 . The outlet conduit  56  is connected to the pump  60 , and the outlet of the pump  60  is connected to a diverting conduit  92 . An outlet  94  of the diverting conduit  92  extends above a levee  96  formed around the ditch  84 . 
     Gradually, the rainwater and run-off collect in the ditch  84 . When the level of water reaches the inlet conduit  26 , the water is allowed to freely enter the conduit  26  and flow into the housing. The direction of the water flow is schematically illustrated by arrows  98 . The water, with the oil particles suspended therein enters the inlet portion  42  of the interior chamber. The absorbent members  80  attract the oil particles that tend to float on the water surface. Water, substantially free from the oil particles, floats under the dividing plate  40 , along the channel  48  into the chamber portion  44 . The liquid level substantially equalizes in the portion  42  and the portion  44  of the interior chamber with the level of water in the trench  84 . Any debris that entered the chamber portions  42  and  44  through the screen  32  is additionally screened by the screen  54  on its path upwardly in the chamber portion  44 . 
     The water, now substantially free from oil and debris, enters the outlet conduit  56 . When the pump  60  is activated, the water is pumped out of the separator housing  12  and into the diverting conduit  92 . From there, the water can be pumped over the levee  96 . When the ditch  84  becomes full with water, as schematically shown in  FIG. 5 , the pump  60  may be turned on either manually or automatically, to be activated based on the water level predetermined by the operator. The water is pumped from the ditch  84  through the separator  10  and over the levee  96 , thereby preventing oil accumulated in the ditch  84  from being released into the surrounding areas outside of the levee  96 . 
     If desired, the level of water in the ditch  84  can be continuously monitored and controlled by the automatic operation of the pump  60 . In the alternative, an operator may inspect the level of liquid in the ditch  84  and start operation of the pump  60  to remove a portion of water from the ditch  84 . From time to time, the operator can inspect the status of the absorbent members  80  by opening the cover  62  and visually inspecting the absorbent members. When the absorbent members  80  become saturated with oil, the can be easily removed from the interior of the housing  12  and new absorbent members can be positioned by dropping them on the screen  54 . Should the screen  54  become clogged with small leaves or other particles, the operator can clean the screen by lifting the covers  62  and  64  and obtaining access to the interior chamber and the screen  54 . 
     The separator apparatus  10  of the present invention requires little monitoring and can function for a long time without repairs or adjustments. When the job in the oilfield is complete, the apparatus  10  can be removed from the ground and transported to the new job site after the water from the housing  12  has been drained. 
     Many changes and modifications can be made in the design of the present invention without departing from the spirit thereof. I therefore pray that my rights to the present invention be limited only by the scope of the appended claims.

Technology Classification (CPC): 2