Abstract:
The invention comprises a section of improved tubing with coupled end connectors and an insert containing at least one electrical wire. The insert has an outside diameter that is approximately equal to the inside diameter of the improved tubing. The insert also has projections at each end such that when two inserts are placed end to end, the projections will mate up. The insert has at least one groove cut into its side and running the length of the insert. The groove is for the placement of a wire for transmission of power to the well bore or for the placement of a wire for transmission of data from the well bore. When a plurality of the inventions are placed end to end, the insert projections line up the electrical connectors and correct mating of the insert projections will result in correct mating of the electrical connectors.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention generally relates to tubing that is used to produce hydrocarbons in a subterranean environment and specifically to an improved tubing having an insert with electrical wiring.  
         BACKGROUND OF THE INVENTION  
         [0002]    Basic artificial lift methods to produce oil and water from a well have improved and changed in recent years. Nearly all methods of artificial lift still employ the connection of a plurality of pipes to form a conduit within a well that has been drilled and cased to allow oil and water to be pumped from the bottom of the well to production tanks at the surface. The production string usually has a pumping device at its lower end that is positioned near the bottom of the well bore that has been prepared for production. Pumping mechanisms such as electrical submersible pumps (ESP) and progressive cavity pumps (PCP) provide the energy needed to bring fluids to the surface through a string of jointed tubing. These pumps normally require an electric motor in order to make them work. Although a multitude of improvements have been made to these pumps over the years, there has been little done to reposition the wires that provide power to the pump from the outside of the tubing to the inside of the tubing.  
           [0003]    For various reasons, those who are skilled in the science of producing fluids from a well have sought out a reliable method of supplying power to the bottom of a well bore. The previously proposed solutions to this problem have been unreliable, expensive, and complicated to install and remove. For example, the currently preferred method of power transmission to the bottom of the well bore is to secure a cable, that contains one or more wires by means of bands that secure the cable to the outside of the production string of tubing. The bands keep the wire adjacent to the tubing so that it does not snag on the production casing or on any objects which might be in the well bore. The bands also support the weight of the cable by securing the cable to the tubing. However, this method is problematic because it exposes the cable and bands to the corrosive elements of the well bore. Furthermore, installing (running) or removing (pulling) the tubing string creates opportunities to separate the cable from the tubing because inclined well bores (the most common type of well bores) increase the chance of the band to hanging up and failing at the gap where two joints of casing have been screwed together. Failure of one or more bands can prevent the removal of the pump or tubing because the annular space between the outside of the production tubing and the inside of the production casing is small and the cable, if not secured to the tubing, can wedge between the casing and the tubing causing the tubing to become stuck. Even if the cable does not break, the insulation on the wire inside the cable can be damaged which can create a short circuit in the electrical circuit, rendering the wire essentially useless. The tubing string then has to be pulled back up to the surface, and the short found and repaired, before the pump can be run back to bottom of the well bore. The problems created by banded external cables are costly and time consuming. Therefore, a need exists for an alternative method of power transmission from the surface to the bottom of the well bore that is both reliable and cost effective.  
           [0004]    One solution to the above stated problem is to employ a plurality of tubing with multiple wires attached to the inside of the tubing instead of the outside of the drill pipe. While this solution alleviates the problem of snagging the wire, it does not solve the problem of exposing the wire to the harsh environment of the produced fluids that are contained within the production tubing. Simply hanging the cable on the inside of the tubing is also problematic because there is no way to support the weight of the cable and the pressure requirements of the pump will be higher due to the added friction between the fluid that is being pumped and the rough exterior of the cable.  
           [0005]    Another solution to the above stated problem is to concentrically position the wires on the exterior of a tube that is inserted and attached to the actual production tubing itself. This solution avoids the problems presented by simply attaching the wire to either the interior or the exterior of the tubing. An example of this technique can be found in U.S. Pat. No. 4,683,944 (the &#39;944 patent) entitled “Drill Pipes and Casings Utilizing Multi-Conduit Tubulars.” The &#39;944 patent discloses a drill pipe with electrical wires positioned inside conduits in the drill pipe wall. However, positioning the wire inside the drill pipe wall significantly decreases the overall pipe wall thickness. In order to overcome the decreased wall thickness, significantly thicker drill pipes will have to be used. Furthermore, the multiple conduits create weak points in the drill pipe in between the conduits. The high rotational stress which the drill pipe encounters in the drilling operations can cause stress fractures in the pipe wall between the multiple conduit tubulars. In an extreme case, high rotational stress can lead to an internal fracture in the drill pipe that disengages the interior wall of the drill pipe from the exterior wall of the drill pipe.  
           [0006]    Furthermore, the manufacture of the multiple conduit drill pipe is a complicated process which is unlike the manufacturing process for conventional drill pipe. Conventional drill pipe is manufactured by attaching male and female pipe connections to opposite ends of a conventional piece of pipe. The two connections are usually welded to the pipe. Multiple conduit pipes must be either extruded with the multiple conduits in place, or the multiple conduits must be drilled or cut out of a conventional drill pipe. In either case, the costs associated with manufacture of multiple conduit drill pipe are high.  
           [0007]    Another problem encountered in the addition of wires to drill pipe, which is not unique to multiple conduits, is the problem associated with creating reliable, secure electrical connections. In conventional drill pipe the individual pipe segments screw together, creating a problem for connecting the wires during the screwing or unscrewing process. This problem can be overcome by using drill pipe that plugs together and that is secured with a threaded coupler. This type of connection is known in the art. The &#39;944 patent discloses a similar type of coupling connection, but requires a planer conduit seal in between the individual pipe segments in order to assure the integrity of the conduit connection. The removable conduit seal is crucial to the method in the &#39;944 patent because a permanently installed conduit seal would be susceptible to damage during manufacture, transportation, storage, and installation of the multiple conduit drill pipe during drilling operations. Installing these conduit seals during the drilling process is also a cumbersome and a time consuming process. Therefore, a need exists for a method of transmitting electrical power to the bottom of a well bore in which the electrical connections are adequately protected from damage and the process of connecting the individual pipe segments is relatively simple and fast.  
           [0008]    The needs identified above exist for production tubing, drill pipe, casing, and/or for any cylindrical pipe used to produce hydrocarbons in a subterranean environment. Therefore, as used herein, the term “tubing” shall mean production tubing, drill pipe, casing, and/or any other cylindrical pipe that is used to produce hydrocarbons in a subterranean environment.  
           [0009]    Since, the previous solutions to the power transmission problem are lacking, a need still exists for an apparatus and method of transmitting power to a well bore in which the wire is not exposed to either the interior or the exterior of the tubing and is operable with any conventional tubing, including without limitation production, casing or drill pipe. Furthermore, a need exists for an apparatus and method for connecting the individual tubing segments together in which the electrical connections are well protected and the connection process is quick and easy.  
         SUMMARY OF THE INVENTION  
         [0010]    The present invention, which meets the needs stated above, is an improved tubing which overcomes the problems presented by earlier inventions involving tubing and electrical wiring combinations. The invention comprises a section of tubing with coupled end connectors and an insert containing at least one electrical wire. The insert has an outside diameter that is approximately equal to the inside diameter of the improved tubing. The insert also has projections at each end such that when two inserts are placed end to end, the projections will mate up. The insert has at least one groove cut into its side and running the length of the insert. The groove is for the placement of a wire for transmission of power to the well bore or for the placement of a wire for transmission of data from the well bore. The groove is installed down the length of the insert. The groove is deep enough so that when a wire is placed inside the groove, the wire does not project beyond the outside diameter of the insert. The insert may contain as many groove and wire combinations as are necessary for the particular application. The wire has an electrical connection at each end of the insert. When the inserts are placed end to end, the insert projections line up the electrical connectors and correct mating of the insert projections will result in correct mating of the electrical connectors.  
           [0011]    The inserts are the same length as the tubing and are installed inside the tubing such that the insert is flush with the first end of the tubing. The inserts are then welded to the tubing or secured to the tubing by some other method. A threaded coupler is then installed on the second end of the tubing to protect the exposed insert and electrical connector. The coupler will also be used to secure the improved tubing together.  
           [0012]    Individual pieces of improved tubing are connected together in a three step process. First the coupler is threaded onto the second end of the tubing. Next, the first end of one tubing member is positioned above the second end of another tubing member. Next, the insert projections are properly aligned so that they will mate together. Then, the two pieces of tubing are plugged together so that the electrical connections engage each other. Finally, the coupler is screwed onto the first end of the tubing so that the two pieces of tubing are secured together. The process may be repeated as necessary to create an elongated string of improved tubing. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0013]    [0013]FIG. 1 is an illustration of the improved tubing without the insert or the coupler.  
         [0014]    [0014]FIG. 2 is an illustration of the insert.  
         [0015]    [0015]FIG. 3 is an illustration of the insert installed in the improved tubing.  
         [0016]    [0016]FIG. 4A is a cross-sectional illustration of the two wire embodiment of the insert taken along line  4 - 4  in FIG. 2.  
         [0017]    [0017]FIG. 4B is a cross-sectional illustration of the three wire embodiment of the insert similar to the two wire embodiment in FIG. 4A.  
         [0018]    [0018]FIG. 5 is an exploded illustration of the connection between the first end of the improved drill pipe and the second end of the improved tubing.  
         [0019]    [0019]FIG. 6 is a cross-section of the two wire embodiment of the insert installed in the improved tubing taken along line  6 - 6  in FIG. 5.  
         [0020]    [0020]FIG. 7 is a cross-section of the two wire embodiment of the insert installed in the improved tubing taken along line  7 - 7  in FIG. 5.  
         [0021]    [0021]FIG. 8 is an illustration of the positioning and alignments steps for the two wire embodiment of the improved tubing.  
         [0022]    [0022]FIG. 9A is an illustration of the plugging step for the two wire embodiment of the improved tubing.  
         [0023]    [0023]FIG. 9B is an illustration of the securing step for the two wire embodiment of the improved tubing.  
         [0024]    [0024]FIG. 10 is an illustration of the positioning and alignment step for the three wire embodiment of the improved tubing. The dashed line indicates the alignment of the wire connectors in the three wire insert embodiment.  
         [0025]    [0025]FIG. 11 is a cross-sectional illustration of the three wire embodiment of the insert taken along line  11 - 11  in FIG. 10.  
         [0026]    [0026]FIG. 12 is an illustration of the plugging step for the three wire embodiment of the improved tubing.  
         [0027]    [0027]FIG. 13 is an illustration of the securing step for the three wire embodiment of the improved tubing.  
         [0028]    [0028]FIG. 14 is a cross-sectional illustration of the three wire embodiment of the insert taken along line  14 - 14  in FIG. 13.  
         [0029]    [0029]FIG. 15 is a detail view of the geometry between the insert, the wire, and the improved tubing around the area indicated by circle  15  in FIG. 14.  
         [0030]    [0030]FIG. 16 is an illustration of a submerged pump in a production situation.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0031]    As used herein, the term “improved tubing” means tubing that is adapted to receive a coupler and that has an insert. FIG. 1 is an illustration of improved tubing  100  without insert  200  (see FIG. 2) or coupler  300  (see FIG. 5). Improved tubing  100  is comprised of three sections: first end  120 , midsection  140 , and second end  160 . First end  120  comprises coarse threads  122 , first end weld joint  124 , and wrench grip  126 . Midsection  140  comprises pipe  142 , pipe first end  144 , and pipe second end  146 . Second end  160  comprises fine threads  162 , second end weld joint  164 , and coupler stop flange  166 . First end  120  and second end  160  may be like those found in U.S. Pat. No. 5,950,744 (the &#39;744 patent) entitled “Method and Apparatus for Aligning Pipe and Tubing.” Typically, first end  120  and second end  160  are manufactured by either casting or forging and pipe  142  is manufactured by some other method (i.e. electric resistance welding or extrusion). The manufacture of improved tubing  100  involves the threading of first end  120  and second end  160  to pipe  142 . While the preferred method of manufacturing first end  120  and second end  160  is threading the two ends of improved tubing  100 , those skilled in the art will be aware of other methods of manufacturing first end  120  and second end  160 . Regardless of the method of manufacture, the inside diameter of first end  120 , midsection  140 , and second end  160  are substantially the same so that when insert  200  engages improved tubing  100 , the outside surface area of insert  200  contacts the inside surface area of improved tubing  100 .  
         [0032]    [0032]FIG. 2 is an illustration of inset  200 . Insert  200  is comprised of insert first end  220 , insert midsection  240 , and insert second end  260 . Insert first end  220  comprises insert first end projection  222  and insert first end electrical connection  224 . Insert midsection  240  comprises insert body  242  and insert groove  244 . Insert second end  260  comprises insert second end projection  262  and insert second end electrical connection  264 . The depressions in insert second end  260  in between insert second end projections  262  match up with the insert first end projections  222 . Likewise, the depressions in insert first end  220  in between insert first end projections  222  match up with the insert second end projections  262 . Thus, when two inserts  200  are coaxially aligned with insert first end  220  facing insert second end  260 , insert first end  220  will mate up with insert second end  260 . Insert  200  also contains insert groove  244  which is a groove cut down the long axis of insert  200 . Insert groove  244  is sufficiently large to accommodate at least one wire  246 . Wire  246  is electrically coupled to insert first end electrical connection  224  and insert second end electrical connection  264  and is used as a medium to transfer electricity from the surface to the bottom of the well bore. Insert first end electrical connection  224  and insert first end electrical connection  264  are single plug connectors similar to the K-25 series electrical connectors produced by Kemlon Products and Development Co. of Pearland, Tex. The K-25 series of single plug electrical connections are able to withstand temperatures up to 500° F. and pressures up to 25,000 psi.  
         [0033]    [0033]FIG. 4A is a cross-section of the two wire embodiment of insert  200  taken along line  44  in FIG. 2. Inset  200  may contain only one wire  246  or may contain a plurality of wires  246 . For simplicity of illustration of the invention, FIGS. 1 through 9B (excluding  4 B) depict the invention with only two wires. In alternative embodiments, wire  246  can be a fiber optic in which case the two electrical connections on insert  200  would be optical connections and the embodiment, the invention could employ a mixture of fiber optics and electrical wires. In the preferred embodiment the invention incorporates three wires such that the three wires each carry the appropriate load of a three phase, 440-volt electrical system, as illustrated in FIGS.  4 B and  10  through  15 . However, the number and type of wires is not meant to be a limitation on the invention as those skilled in the art will be aware of how best to configure the invention with fiber optics, electrical wiring, or other connections within insert groove  244  of improved drill pipe  100 .  
         [0034]    [0034]FIG. 3 is an illustration of improved tubing  100  with insert  200  installed. Insert  200  is sized lengthwise so that when insert  200  is inserted into improved tubing  100 , insert first end projection  222  is flush with first end  120  and insert second end projection  262  is the only portion of insert  200  that is projecting beyond second end  160 . As seen in FIG. 6, insert  200  is circumferentially sized such that the outer diameter of insert  200  is sufficiently equal to the inside diameter of improved tubing  100 . Insert groove  244  is sufficiently deep in insert body  242  so that wire  246  does not extend beyond the outer diameter of insert  200 , yet is not deep enough to affect the structural integrity of insert  200 . Insert  200  is coaxially positioned inside improved tubing  100  and secured in place. In the preferred embodiment, insert  200  is the same material as improved tubing  100  and is secured in place by welding. However, insert  200  can be made of any material suitable for drilling operations including various metal alloys, fiberglass, plastic PVC, polymer, or any other material as determined by those of skill in the art. Likewise, insert  200  can be secured in place by welding, glue, heat shrinking, expanding, set screws, or any other method as determined by those skilled in the art. Heat shrinking is defined as a process in which the outer pipe is heated so that the outer pipe expands, the insert is positioned inside the pipe, and the pipe is allowed to cool so that it contracts and secures the insert in place. Expanding is a process in which a tool (expander), having a slightly larger outside diameter than the inside diameter of the insert, is pulled forcibly through the insert causing the outside surface of the insert to expand and grip the inside of the improved tubing. Set screws is a process in which the improved tubing and insert are tapped and threaded and a screw is inserted through the improved tubing and insert to secure the insert in place relative to the pipe.  
         [0035]    [0035]FIG. 5 is an exploded illustration of the connection between two separate pieces of improved tubing  100  with insert  200  installed and coupler  300  positioned for installation on first end  120  and drill pipe second end  160 . Coupler  300  is annular in shape and contains coupler fine threads  302  and coupler coarse threads  304 . Coupler fine threads  302  are configured for screwing engagement with drill pipe fine threads  162 . Coupler coarse threads  304  are configured for screwing engagement with drill pipe coarse threads  122 . The pitch of drill pipe coarse threads  122  and drill pipe fine threads  162  are different pitch so that coupler  300  can only mate up with improved tubing  100  in one orientation. Similarly, when coupler fine threads  302  and coupler coarse threads  304  engage pipe coarse threads  122  and drill pipe fine threads  162 , the coarse threads and the fine threads do not interfere with the threading process of each other. As seen in FIG. 7, coupler stop flange  166  has a larger cross-sectional area than fine threads  162  and acts as a stop for coupler  300  so that coupler  300  does not go past second end  160 . The outside diameter of coupler  300  is sufficiently similar to pipe wrench grip  126  so that when the user is attaching the individual pieces of improved drill pipe  100  together, a pipe wrench will fit onto both pipe wrench grip  126  and coupler  300  without undue adjustment of the pipe wrench. Coarse threads  122  and coupler coarse threads  304  are tapered so that they may be completely engaged with a minimal amount of rotations after first end  120  and second end  160  have been plugged together. Coupler  300  is also sufficiently long so that when coupler  300  is completely screwed onto second end  160  and abuts coupler stop flange  166 , coupler  300  extends past insert second end projection  262 . It is important that coupler  300  extend past insert second end projection  262  because improved tubing  100  will typically be stored, transported, and handled with coupler  300  installed on second end  160  and coupler  300  will protect insert second end  260  and specifically insert second end electrical connection  264  from damage.  
         [0036]    [0036]FIG. 8 is an illustration of coupler  300  installed on second end  160  just prior to connection of two pieces of improved tubing  100 . FIG. 8 is representative of how improved tubing  100  will be stored, transported, and handled. In FIG. 8, coupler  300  extends past insert second end projection  262  and insert second end electrical connection  264 .  
         [0037]    [0037]FIGS. 8, 9A, and  9 B illustrate the process of attaching two sections of improved tubing  100  together. In attaching the two sections of improved tubing  100  together, as far as the scope of this invention is concerned, it does not matter whether the second end  160  of one section of improved tubing  100  is above the first end  120  of the other section of improved tubing  100  or vice-versa. The improved tubing  100  may also be connected in the horizontal. However, the preferred embodiment and industry standard is to place the second end  160  above the first end  120 . The attachment process comprises four steps: positioning, aligning, plugging, and securing. First, in the positioning step the two sections of improved tubing  100  are positioned over one another with a second end  160  of one improved tubing  100  facing the first end  120  of the other improved tubing  100 . As seen in FIG. 8, the aligning step consists of rotating one or both sections of improved tubing  100  such that the insert second end projection  262  in one section of improved tubing  100  will properly mate with the insert first end projection  222  in the other section of improved tubing  100 .  
         [0038]    When the two sections of improved tubing  100  are properly aligned, the two sections of improved tubing  100  may be plugged together. FIG. 9A is an illustration of the plugging step in which two sections of improved tubing  100  are plugged together. In the plugging step, the second end  160  of one section of improved tubing  100  is lowered onto the first end  120  of the other section of improved tubing  100  until the two sections of improved tubing  100  contact each other and/or the two inserts  200  fully mate with each other. To properly mate, insert second end projections  262  will fill the depression between insert first end projections  222  and insert first end projections  222  will fill the depression between insert second end projections  262 . When insert first end projection  222  and insert second end projection  262  properly mate, insert first end electrical connection  224  and insert second end electrical connection  264  will electrically couple and provide an electrical connection which will tolerate the harsh environment of the well bore. After the two improved tubing  100  are plugged together, they are secured by screwing coupler  300  onto first end  120 .  
         [0039]    [0039]FIG. 9B is an illustration of two sections of improved tubing  100  secured together by coupler  300 . Coupler  300  is secured to first end  120  by pipe wrenches (not shown) which grip coupler  300  and pipe wrench grip  126  and torque coupler  300  until coupler  300  is firmly screwed onto drill pipe first end  120 . The two sections of improved tubings  100  may then be used in the production process.  
         [0040]    [0040]FIGS. 10 through 14 illustrate a three wire embodiment. The manufacture of the three wire improved drill pipe is similar to the manufacture of the two wire improved tubing. Likewise, the assembly of a plurality of three wire improved tubing is similar to the assembly of a plurality of two wire improved tubing. FIG. 10 is an illustration of the alignment step for a three wire embodiment of the insert in which coupler  300  is installed on second end  160 . The dashed line in FIG. 10 indicates the alignment of inset first end electrical connection  224  and insert second end electrical connection  264 . When the two electrical connectors are properly aligned, insert first end projection  222  and insert second end projection  262  are also properly aligned. FIG. 11 is a cross-sectional illustration of the three wire embodiment of insert  200  and improved tubing  100  taken along line  11 - 11  in FIG. 10. FIG. 12 is an illustration of the plugging step for the three wire embodiment of insert  200  taken along line  11 - 11  in FIG. 10. FIG. 13 is an illustration of the securing step of two pieces of improved tubing  100  with the three wire embodiment of insert  200  and the coupler disengaged from the first end of the tubing.  
         [0041]    [0041]FIG. 14 is a cross-section of the three wire embodiment of the insert taken along line  14 - 14  in FIG. 13. Insert  200  in the three wire embodiment is similar to insert  200  in the two wire embodiment in that the inside diameter of pipe  142  is substantially the same as the outside diameter of inset body  242 . FIG. 15 is a detail view of the geometry between insert  200 , wire  246 , and improved tubing  100  around the area indicated by circle  15  in FIG. 14. FIG. 15 illustrates the point that insert groove  244  is cut into insert body  242  so that wire  246  does not project above the outer surface of insert body  242 .  
         [0042]    [0042]FIG. 16 is an illustration of a submerged pump in a production situation. FIG. 16 shows multiple pieces of improved tubing  100  with the inserts installed (not shown). Power comes from an external source  402  and is stepped down in transformer  404 , is routed through vent box  406 , and goes to wellhead  408 . Power is transmitted down tubing pump  412  and or motor  414 . Well bore  418  is typically cased with casing  416 .  
         [0043]    With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.