Abstract:
A mud tank for processing drilling mud during drilling operations wherein the interior of the mud tank has sloping walls to guide sinking aggregate toward a sand trap disposed at the point of convergence thereof. The sand trap is comprised of the convergences area of the sloping walls and an inverted V-shaped cap member located thereabove along the entire length with ¼″ gaps provided between the edges of the cap and their respective sloping walls. Aggregate is drawn through the gaps into the sand trap by a sand pump that provides a suction line therein. A center-divider within the mud tank separates the tank into a dirty tank and a clean tank to provide redundant cleaning operation for more effective removal of aggregate.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to drilling mud and, more specifically, to a mud tank for processing drilling mud during drilling operations. 
   In drilling technology, drilling mud is used for removal of drill cuttings and to maintain hydrostatic equilibrium within the wellbore by pumping the drilling mud of a predetermined density down the drill string to the nozzles on the drill bit, whereupon the mud and cuttings are transported back up through the surface casing to a mud pit where it is screened to remove large particles and de-sanded prior to reuse. 
   The present invention provides a mud tank having a base with peripherally depending walls forming a receptacle for processing the wellbore aggregate by placing a screen shaker over the receptacle to remove particles larger than the screen mesh as the wellbore mixture is pumped into the receptacle. The receptacle is designed with divergent walls extending from a culvert spanning the length of the receptacle forming egress of the wellbore mixture for further processing. 
   Straddling the culvert is a cap, also having divergent walls extending from the cap apex with the cap divergent walls fixedly spaced away a predetermined distance from the receptacle divergent walls providing passage of the mud slurry into the culvert while preventing larger particles from entering. Preferably the spacing is approximately ¼ inch along both longitudinal cap edges. 
   Accordingly, the aggregate within the mixture hereinafter referred to as sand, will be channeled to the culvert and moved for further processing to the desander, as opposed to falling out of solution into the nooks and crannies of the prior art mud tanks requiring additional processing tasks. 
   Furthermore, the culvert cap prevents larger particles from impeding the flow to the desander having drain slits extending the length of both sides of the cap. 
   2. Description of the Prior Art 
   There are other tanks, which provide for fluid flow. While these tanks may be suitable for the purposes for which they where designed, they would not be as suitable for the purposes of the present invention as heretofore described. 
   It is thus desirable to provide a tank for processing drilling mud having means for channeling the wellbore mixture into a desander. 
   It is further desirable to provide said tank with a culvert having a cap thereover incorporating means for regulating particle size and to prevent blockage of the culvert flow. 
   SUMMARY OF THE PRESENT INVENTION 
   The present invention is a mud tank having a first and second compartment, each forming a tank with an aperture in the common wall separating the tanks serving as an overflow from one tank to the other. 
   All mud is drawn out of the front tank and all mud is deposited into the rear tank, which creates a flow from the rear tank to the front tank. 
   There are only two paths for mud to get to the front tank, both through the sand trap and through the overflow in the common wall forming a center divider. 
   Mud will take the path of least resistance, most often this is the sand trap at the bottom of the tank. This loads the sand trap pipe and forces the mud to flow from the rear tank to the front tank. 
   The desander pump draws a suction on the forward sand trap, which keeps the mud and sand moving to the desander pump with a small amount of mud flowing from the front tank into the sand trap. Because the mud from the shaker and desander cones is deposited into the rear tank, the rear tank will overflow through the center divider to the front tank. Now, mud in the front tank is clean with the desander cones continuously reprocessing the mud so that the mud in the front tank gets cleaner and cleaner. The suction point for the downhole pump is above the bottom of the tank there by clean mud is drawn off the top of the front mud tank. 
   A primary object of the present invention is to provide a drilling mud tank that prevents the accumulation of sediment within the mud tank. 
   Another object of the present invention is to provide a drilling mud tank having a base with walls depending therefrom with a substantially center partition dividing the tank into a first and second compartment with an aperture for passage of drilling mud therebetween. 
   Yet another object of the present invention is to provide a drilling mud tank having a longitudinal channel with walls divergently extending from a trough whereby sand will gravity feed into the channel. 
   Still yet another object of the present invention is to provide a drilling mud tank wherein said channel has a spaced apart cover with said space providing for the flow of mud and sand into the channel while preventing passage of larger particles. 
   Another object of the present invention is to provide a mud tank wherein said covered channel is in communication with a desander pump. 
   Yet another object of the present invention is to provide a mud tank having a port for supplying a source of clean drilling mud. 
   Still yet another object of the present invention is to provide a mud tank wherein said desanding process deposits cleaned mud and wellbore mud aggregate into a compartment in communication with a second compartment through a pair of passages. 
   Another object of the present invention is to provide a mud tank for processing drilling mud having a pair of tanks with a divider possessing an aperture for the mud to overflow from one compartment into the other. 
   Yet another object of the present invention is to provide a mud tank for processing drilling mud having a pair of tanks with a divider possessing an aperture positioned below the channel cap and extending to the channel walls forming passage to the desander cones via the desander pump. 
   Still yet another object of the present invention is to provide a mud tank that cycles all wellbore material in an efficient manner providing clean drilling mud at an economical cost. 
   Additional objects of the present invention will appear as the description proceeds. 
   The present invention overcomes the shortcomings of the prior art by providing a mud tank for processing drilling mud during drilling operations that overcomes the limitations of the prior art. 
   The present invention provides a mud tank having a base with peripherally depending walls forming a receptacle for processing the wellbore aggregate by placing a screen shaker over the receptacle to remove particles larger than the screen mesh as the wellbore mixture is pumped into the receptacle. The receptacle is designed with divergent walls extending from a culvert spanning the length of the receptacle forming egress of the wellbore mixture for further processing. 
   Straddling the culvert is a cap, also having divergent walls extending from the cap apex with the cap divergent walls fixedly spaced away a predetermined distance from the receptacle divergent walls providing passage of the mud slurry into the culvert while preventing larger particles from entering. Preferably the spacing is approximately ¼ inch along both longitudinal cap edges. 
   Accordingly, the sand within the mixture will be channeled to the culvert and moved for further processing to the desander, as opposed to falling out of solution into the nooks and crannies of the prior art mud tanks requiring additional processing tasks. 
   Furthermore, the culvert cap prevents larger particles from impeding the flow to the desander having drain slits extending the length of both sides of the cap. 
   The foregoing and other objects and advantages will appear from the description to follow. In the description reference is made to the accompanying drawings, which forms a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. In the accompanying drawings, like reference characters designate the same or similar parts throughout the several views. 
   The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     In order that the invention may be more fully understood, it will now be described, by way of example, with reference to the accompanying drawing in which: 
       FIG. 1  is an illustrative view of the present invention in use; 
       FIG. 2  is an illustrative view of the present invention in use; 
       FIG. 3  is a side view of the present invention; 
       FIG. 4  is an external view of the present invention in use; 
       FIG. 5  is a perspective view of the present invention; 
       FIG. 6  is a perspective view of the present invention; 
       FIG. 7  is a detailed view of the present invention in use; 
       FIG. 8  is a detailed view of the present invention in use; 
       FIG. 9  is orthographic views of the present invention; and 
       FIG. 10  is orthographic views of the present invention. 
   

   DESCRIPTION OF THE REFERENCED NUMERALS 
   Turning now descriptively to the drawings, in which similar reference characters denote similar elements throughout the several views, the figures illustrate the Improved Drilling Mud Tank Assembly of the present invention. With regard to the reference numerals used, the following numbering is used throughout the various drawing figures. 
   
     
       
             
             
           
         
             
                 
             
           
           
             
               10 
               Improved Drilling Mud Tank Assembly of the present invention 
             
             
               12 
               mud tank 
             
             
               14 
               sand trap assembly 
             
             
               16 
               center wall 
             
             
               18 
               shaker screen 
             
             
               20 
               desander cone 
             
             
               22 
               dirty tank of 12 
             
             
               24 
               clean tank of 12 
             
             
               26 
               cap of 14 
             
             
               28 
               large debris 
             
             
               30 
               sand 
             
             
               32 
               sand dump chute 
             
             
               34 
               trap gap 
             
             
               36 
               suction port 
             
             
               38 
               desander pump 
             
             
               40 
               desander cone inlet 
             
             
               42 
               cone return line 
             
             
               44 
               sloped walls of 12 
             
             
               46 
               overflow spillway 
             
             
               48 
               dirty mud 
             
             
               50 
               clean mud 
             
             
               52 
               extra outlet to drill 
             
             
               54 
               sand trap cutout 
             
             
                 
             
           
        
       
     
   
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The following discussion describes in detail one embodiment of the invention. This discussion should not be construed, however, as limiting the invention to those particular embodiments, practitioners skilled in the art will recognize numerous other embodiments as well. For definition of the complete scope of the invention, the reader is directed to appended claims. 
     FIG. 1  is an illustrative view of the present invention  10  in use. The present invention  10  is a mud tank assembly  10  that is part of a mud cleaning system. The mud tank  12  serves as a reservoir for the mud that a well driller uses to drill with. The mud is a mixture of bentonite (clay) and water. The mud is pumped down the drill pipe while the well is being drilled. The mud comes out of the drill pipe at the bottom of the well and carries the rocks and sand from the bottom to the surface. The mud carrying the solids is pumped via the sand guzzler to a shaker  18  which is a vibrating screen that separates the rock and large items from the mud. The mud and sand fall through the screen into the mud tank. The large items fall onto the ground. The mud in the tank is then pumped through desander cones  20  that spin the mud so that the sand is thrown to the outside of a vortex. The clean mud leaves the top of the cone  20  and returns to the mud tank while the sand leaves the bottom of the cone  20  and falls to the ground. The mud tank assembly  10  includes the mud tank  12  divided interiorly into a rear dirty section  22  and a front clean section  24  by a center wall  16  and a sand trap assembly  14  covering the bottom of the tank  12 . 
     FIG. 2  is an illustrative view of the present invention  10  in use. The mud tank  12  is a major part of the system. The mud carrying the sand falls from the shaker  18  into the dirty section of the tank  12 . The tank  12  has sides that slope down toward the center. In the bottom of the tank  12 , at the center is a sand trap formed by an inverted “V” cap welded to the bottom of the tank  12 . There is a ¼″ gap between the “V” sides of the cap that run the length of the tank  12  in both sections thus allowing the sand to be pulled into the trap gap. A desander pump draws mud from the tank  12  via the sand trap. Because there is a ¼″ gap or opening in the sand trap, the sand is drawn in the entire length of the sand trap. That is how the inside of the tank  12  is kept clean. Large debris  28  is prevented entry into the dirty section of the mud tank  12  by the shaker  18  and the removed sand  30  is deposited by the sand dump chute 
     FIG. 3  is a side view of the present invention  10 . The present invention  10  provides a mud tank  12  that controls the flow of sand within by having sloped walls so sand is diverted into a suction and out to the desander pump. A sand trap runs along the bottom of the tank  12  that spreads the suction across the length thereof. The tank  12  is divided into two parts that separates the dirty mud from the clean mud. A shaker  18  is set over the dirty side and the clean mud is pumped back down the drill hole from the clean side. 
     FIG. 4  is an external view of the present invention  10  in use. The mud carrying the sand falls from the shaker  18  into the dirty section of the tank  12 . The tank  12  has sides that slope down toward the center. In the bottom of the tank  12 , at the center is a sand trap which is an inverted “V”-shaped trap cap welded to the bottom of the tank  12 . There is a ¼″ gap between the “V” sides that run the length of the tank  12  on both sides thus pulling the sand through the gap into the trap. A desander pump draws the sand from the sand trap through a suction port and it is delivered to the desander cones  20  via the desander cone inlet  44 . The desander cones  20  create a vortex that propel the heavier sand particles outward while drawing the cleaned mud out of the top into the cone return line  42  and back into the mud tank  12  where it is reprocessed. 
     FIG. 5  is a perspective view of the present invention  10 . Shown is a perspective view of the present invention  10  providing a tank  12  that controls the flow of sand within having a sand trap assembly  14  integral therewith including sloped walls  44  and the trap cap  26  at their juncture with a trap gap  34  therebetween through which sand is diverted therein and into a suction port  36  and out to the desander pump. The sand trap  14  runs along the bottom of the tank  12  and spreads the suction thereacross. The tank  14  is divided into two parts by a center wall  16  with an overflow spillway  46  that separates the dirty mud from the clean mud. A shaker is set over the dirty side  22  and the clean mud is pumped back down the drill hole from the clean side  24 . 
     FIG. 6  is a perspective view of the present invention  10 . Shown is a perspective view of the present invention  10  providing a tank  12  that controls the flow of sand within having sloped walls  44  so sand is diverted into a suction port  36  and out to the desander pump. A sand trap  14  runs along the bottom of the tank  12  that spreads the suction across the length thereof. The tank  12  is divided into two parts that separate the dirty mud  48  from the clean mud  50 . A shaker is set over the dirty side  22  and the clean mud  50  is pumped back down the drill hole from the clean side  24 . The dirty mud  50  in the dirty section  22  is high, therefore it will flow through the suction port  36  to the desander pump via the sand trap  14 . 
     FIG. 7  is a detailed view of the sand trap  14  in use. The sand  30  sinks to the bottom of the dirty section  22  and is guided to the sand trap  14  by the sloped walls  44 . The sand  30  enters the sand trap  14  through the gaps  34  between the walls  44  and the cap  26  and is subsequently drawn therethrough past the clean section to the desander pump  38 . 
     FIG. 8  is a detailed view of the present invention  10  in use. Mud from drilling is dumped on the shaker screen  18  and the sand  30  sinks to the bottom of the dirty section  22  and is guided to the sand trap  14  by the sloped walls  44 . The sand  30  enters the sand trap  14  through the gaps  34  between the walls  44  and the cap  26  and is subsequently drawn therethrough past the clean section to the desander pump  38 . 
     FIG. 9  is a plurality of orthographic views of the mud tank  12  of the present invention  10 . Shown are the primary components of the mud tank  12  including the suction port  36 , the center divider  16 , the extra outlet to the drill  52 , the sand trap  14 , the sand trap cutout  54  and the sloped walls  44  and cap  26  which define the sand trap  14 . 
     FIG. 10  is a plurality of orthographic views of the present invention  10 . Shown is the mud tank  12 , the suction port  36 , the extra outlet to drill  52 , the center divider  16 , the sand trap  14  and its gaps  34 . 
   It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. 
   While certain novel features of this invention have been shown and described and are pointed out in the annexed claims, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention. 
   Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.