Patent Publication Number: US-8110741-B2

Title: Composite coiled tubing end connector

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. patent application Ser. No. 10/442,680, filed May 21, 2003, now U.S. Pat. No. 7,498,509, which is a continuation-in-part of U.S. patent application Ser. No. 09/410,605, filed Oct. 1, 1999, which is a continuation-in-part of U.S. patent application Ser. No. 09/368,333, filed Aug. 3, 1999, which is a continuation of U.S. patent application Ser. No. 08/721,135, filed Sep. 26, 1996, now U.S. Pat. No. 5,988,702, which claims priority to U.S. Provisional Application Ser. No. 60/005,377, filed Sep. 28, 1995. 
     U.S. patent application Ser. No. 10/442,680, identified above, is also a continuation-in-part of U.S. patent application Ser. No. 09/678,577, filed Oct. 3, 2000, which claims priority to U.S. Provisional Application Ser. No. 60/157,614, filed Oct. 4, 1999. 
     All of the above-referenced patent applications are expressly incorporated by reference herein in their entireties. 
    
    
     FIELD OF THE INVENTION 
     This application relates generally to connectors for use with a spoolable pipe constructed of composite material and more particularly to a field serviceable connector for use in such applications. 
     BACKGROUND OF THE INVENTION 
     A spoolable pipe in common use is steel coiled tubing which finds a number of uses in oil well operations. For example, it is used in running wireline cable down hole with well tools, such as logging tools and perforating tools. Such tubing is also used in the workover of wells, to deliver various chemicals downhole and perform other functions. Coiled tubing offers a much faster and less expensive way to run pipe into a wellbore in that it eliminates the time consuming task of joining typical 30 foot pipe sections by threaded connections to make up a pipe string that typically will be up to 10,000 feet or longer. 
     Steel coiled tubing is capable of being spooled because the steel used in the product exhibits high ductility (i.e. the ability to plastically deform without failure). The spooling operation is commonly conducted while the tube is under high internal pressure which introduces combined load effects. Unfortunately, repeated spooling and use causes fatigue damage and the steel coiled tubing can suddenly fracture and fail. The hazards of the operation and the risk to personnel and the high economic cost of failure in down time to conduct fishing operations forces the product to be retired before any expected failure after a relatively few number of trips into a well. The cross section of steel tubing expands during repeated use resulting in reduced wall thickness and higher bending strains with associated reduction in the pressure carrying capability. Steel coiled tubing presently in service is generally limited to internal pressures of about 5000 psi. Higher internal pressure significantly reduces the integrity of coiled tubing so that it will not sustain continuous flexing and thus severely limits its service life. 
     It is therefore desirable to provide a substantially non-ferrous spoolable pipe capable of being deployed and spooled under borehole conditions and which does not suffer from the structural limitations of steel tubing and which is also highly resistant to chemicals. Such non-ferrous spoolable pipe often carries fluids which may be transported from the surface to a downhole location as in the use of coiled tubing to provide means for treating formations or for operating a mud motor to drill through the formations. In addition, it may be desirable to pump devices through the spoolable pipe such as through a coiled tubing bore to a downhole location for various operations. Therefore, an open bore within the spoolable pipe is essential for some operations. 
     In the case of coiled tubing, external pressures can also be a major load condition and can be in excess of 2500 psi. Internal pressure may range from 5,000 psi to 10,000 psi in order to perform certain well operations; for example, chemical treatment or fracturing. 
     Tension and compression forces on coiled tubing are severe in that the tubing may be forced into or pulled from a borehole against frictional forces in excess of 20,000 lbf. 
     For the most part prior art non-metallic tubular structures that are designed for being spooled and also for transporting fluids, are made as a hose whether or not they are called a hose. An example of such a hose is the Feucht structure in U.S. Pat. No. 3,856,052 which has longitudinal reinforcement in the side walls to permit a flexible hose to collapse preferentially in one plane. However, the structure is a classic hose with vulcanized polyester cord plies which are not capable of carrying compression loads or high external pressure loads. Hoses typically use an elastomer such as rubber to hold fiber together but do not use a high modulus plastic binder such as epoxy. Hoses are designed to bend and carry internal pressure but are not normally subjected to external pressure or high axial compression or tension loads. For an elastomeric type material such as used in hoses the elongation at break is so high (typically greater than 400 percent) and the stress-strain response so highly nonlinear; it is common practice to define a modulus corresponding to a specified elongation. The modulus for an elastomeric material corresponding to 200 percent elongation typically ranges from 300 psi to 2000 psi. The modulus of elasticity for typical plastic matrix material used in a composite tube is from 100,000 psi to 500,000 psi or greater, with representative strains to failure of from 2 percent to 10 percent. This large difference in modulus and strain to failure between rubber and plastics and thus between hoses and composite tubes is what permits a hose to be easily collapsed to an essentially flat condition under relatively low external pressure and eliminates the capability to carry high axial tension or compression loads while the higher modulus characteristic of the plastic matrix material used in a composite tube is sufficiently stiff to transfer loads into the fibers and thus resist high external pressure and axial tension and compression without collapse. The procedure to construct a composite tube to resist high external pressure and compressive loads involves using complex composite mechanics engineering principles to ensure that the tube has sufficient strength. It has not been previously considered feasible to build a truly composite tube capable of being bent to a relatively small diameter, and be capable of carrying internal pressure and high tension and compression loads in combination with high external pressure requirements. Specifically a hose will not sustain high compression and external pressure loads. 
     In operations involving spoolable pipe, it is often necessary to make various connections such as to interconnect long sections or to connect tools or other devices into or at the end of the pipe string. With steel coiled tubing, a variety of well known connecting techniques are available to handle the severe loads encountered in such operations. Threaded connections as well as welded connections are easily applied and meet the load requirements described. 
     Grapple and slip type connectors have also been developed for steel coiled tubing to provide a low profile and also be field serviceable. These steel tubing connectors are not applicable to the composite coiled tubing that is now being developed. One such connector is shown in U.S. Pat. No. 4,936,618 to Sampa et al showing a pair of wedge rings for making a gripping contact with the coiled tubing. 
     The PETRO-TECH Tools Incorporated catalog shows coiled tubing E-Z Connectors, Product Nos. 9209 to 9211 that are also examples of a slip type steel coiled tubing connector. 
     Another connector for reeled thin-walled tubing is shown in U.S. Pat. No. 5,156,206 to Cox and utilizes locking slips for engaging the tubing in an arrangement similar to the Petro-Tech connector. 
     U.S. Pat. No. 5,184,682 to Delacour et al shows a connector having a compression ring for engaging a rod for use in well operations, again using a technique similar to a Petro-Tech connector to seal against the rod. 
     These commercial coiled tubing connectors will not seal properly as configured to a composite pipe partially because of circumferential deformation of the pipe inwardly when the connector is made up on composite pipe and also because the external surface of a composite tube or pipe is not as regular in OD tolerance which causes sealing problems. 
     U.S. Pat. No. 4,530,379 to Policelli teaches a composite fiber tubing with a structural transition from the fiber to a metallic connector. The fibers may be graphite, carbon, aramid or glass. The FIG. 4 embodiment can be employed in a fluid conveyance pipe having bending loads in addition to internal pressure loads and in structural members having bending and axial stiffness requirements. 
     There are many connectors designed for application to elastomeric hoses and tubes such as shown in U.S. Pat. No. 3,685,860 to Schmidt, U.S. Pat. No. 3,907,335 to Burge et al, but sealing to these hoses is substantially different in that the hose body itself serves as a sealing material when pressed against connecting members. A composite pipe is too rigid to function in this way. U.S. Pat. No. 4,032,177 to Anderson shows an end fitting for a non-metallic tube such as a plastic tube and having a compression sleeve and a tubing reinforcing insert but here again the tube itself is deformable to the extent of effecting a seal when compressed by the coupling. 
     Another coupling for non-metallic natural gas pipe is shown in U.S. Pat. No. 4,712,813 to Passerell et al and shows a gripping collet for engaging the outer tubular surface of the pipe and a sealing arrangement for holding internal gas pressure within the pipe but no inner seals are on the pipe and seals cannot be changed without disturbing the gripping mechanism. 
     U.S. Pat. No. 5,351,752 to Wood et al shows a bonded connector for coupling composite tubing sections for pumping a well. The composite tubing has threaded fittings made of composite materials which are bonded to the tubing. 
     SUMMARY OF THE INVENTION 
     In accordance with embodiments of the invention, a connector is provided for use with composite spoolable pipe such as for use in line pipe, production tubing, well logging and workover operations in oil wells. The pipe which is spoolable is comprised of an outer composite structure containing several plies of high strength and stiffness fibers embedded in a resin material such as epoxy. The fibers are oriented to resist internal and external pressure and provide low bending stiffness. Fibers of high strength and modulus are embedded and bonded into a matrix that keeps the fibers in position, acts as a load transfer medium and protects the fibers from environmental damage. The plastic binder in which the fibers are embedded to form the matrix will have a modulus of elasticity (hereinafter modulus) that exceeds 100,000 psi. Typically, a liner may be employed in the pipe to serve as a structural member, one function of which is pressure containment to resist leakage of internal fluids within the tubing. A wear surface may be employed as an outer layer and may be comprised of a binder containing particles of a tough material. 
     In one embodiment, a connector for attaching a composite pipe to a service member can include a service end, a slip nut, a slip, a seal carrier, and an energy conductor. The service end can have a first coupling surface for connecting the pipe with the service member and a second coupling surface for assembling the service end with the pipe. The slip nut can be disposed about the outer surface of the pipe and can be engaged with the second coupling surface on the service end. The slip can be positioned about the outer surface of the pipe and can be engaged by the service end and the slip nut to compress the slip into gripping contact with the pipe upon progressive engagement of the service end with the slip nut. The slip can have teeth formed on the inner surface thereof for engaging the outer surface of the pipe. The seal carrier can be positioned in a bore of the pipe when the connector is coupled to the pipe. The seal carrier can be positioned in the bore of the pipe at a location radially opposite the slip to resist deformation of the pipe when the slip is compressed into gripping contact with the pipe. The energy conductor can be embedded within and surrounded by a material of the service end for connection with an energy conductor within the composite pipe. 
     In one aspect, the seal carrier can be removeably and replaceably positionable within a bore of the service end. 
     In one aspect, the seal carrier and the service end can be of unitary construction. 
     In accordance with one embodiment of the present invention, a connector provides a means for its being secured to an end of such a composite tube or pipe in any one of numerous termination applications including, end connectors, joint splices, service or tool connectors, to name a few. The connector is arranged to be field serviceable and also to maintain the full design ratings of the pipe string and components being connected (such as in tension, compression and pressure). The composite pipe body is generally rigid and therefore the structural integrity and geometry of the pipe must be preserved as the connector is assembled, run and placed in service on the composite spoolable pipe. The connector utilizes a service end which is arranged about the end of a composite tube, a slip nut, also encompassing the pipe, is arranged to be threaded into the inner end of the service end and when threadedly pulled toward one another, these sections act against a load slip system to compress teeth on the slip into the outer surface of the composite pipe. These teeth must be sized and shaped to provide a unitary structure with the composite materials when the teeth are compressed into the composite pipe. In this respect, the load slip is provided with pointed teeth that are capable of penetrating the wear surface and at least one outer ply of the composite tube and thereby access a load transfer capability that encompasses the resin matrix and at least one layer of fiber. A slip load support mandrel may be positioned in the inner bore of the composite pipe establishes hoop strength within the composite pipe and thereby provides a backup to the load slip to insure that its teeth are properly embedded into the plies of composite materials. The slip teeth are arranged so that they penetrate beyond the outermost surface and into the composite body to an extent that permits transfer of load into the composite body. 
     In accordance with one embodiment of the present invention, the end connector includes a service end, a slip nut disposed about the outer surface of the composite pipe and engageable with the service end, and a slip positioned about the outer surface of the pipe and engaged by the service end and the slip nut. Progressive engagement of the service end relative to the slip nut radially compresses the slip into gripping contact with the pipe. The slip preferably includes pipe-engaging teeth that are sized and shape to penetrate into an outer layer of the composite pipe. A seal carrier is received within the service end and within the pipe and carries one or more seal members, such as an elastomeric O-ring, to seal between the pipe and the seal carrier. The seal carrier is positioned in the pipe bore at a location radially opposite the slip to resist deformation of the pipe when the slip is compressed into gripping contact with the pipe. 
     In contrast to the connector embodiments described above, the end connector of the first alternative embodiment does not require a separate load support member. Instead, by positioning the seal carrier radially opposite the slip, the seal carrier establishes a seal between the pipe bore while concomitantly resisting deformation of the pipe from the radially compressive forces applied by the slip. Preferably, the seal carrier is of single piece, unitary construction. In addition, the seal member or seal members carried by the seal carrier can also be positioned radially opposite the slip. In this arrangement, the radially compressive force from the slip can operate to enhance the sealing relationship between the seal members and the interior of the pipe. 
     In accordance with further aspect of the present invention, a connector for connecting a first composite pipe with a second composite pipe can be provided. The pipe-to-pipe connector of the present invention includes a service end for receiving an end of the first pipe and a slip nut for receiving an end of the second pipe. The service end is engageable with the slip nut. First and second slips are positioned about the first and second pipes, respectively. Progressive engagement of the service end with the slip nut compresses the first slip into contact with the first composite pipe while at the same time compressing second slip nut into contact with the second pipe. A double seal carrier is positioned within the end of the first pipe and within the end of the second pipe. A first seal member is provided on the double seal carrier to sealingly engage the inner surface of the first pipe. A second seal member is provided on the double seal carrier to sealingly engage the inner surface of the second pipe in a sealing relationship. 
     The double seal carrier of the pipe-to-pipe connector of the present invention is preferably of single piece, unitary construction. The one piece double seal carrier establishes a seal between the connector and the composite pipes and, in addition, resists deformation of the pipes due to the radially compressive forces applied by the first and second slips. Preferably, the double seal carrier is positioned within the first and second composite pipes such that the first seal member is located radially opposite the first slip and the second seal member is located radially opposite the second slip. As discussed above, this arrangement can enhance the fluid seal provided by the seal members. The double seal carrier can include a raised annular shoulder that axially engages both the end of the first pipe and the end of the second pipe. 
     In accordance with one embodiment of the present invention, the seal carrier of the end connector can be replaced with a generally annular, integral seal positioned at the end of the composite pipe. The integral seal can be formed from a portion of a layer of the pipe to provide the primary fluid seal between the composite pipe and the end connector. By folding a layer of the composite member radially outward at the end of the composite pipe, the integral seal can be formed having a seal surface for engaging the service end of the end connector in sealing relationship. Preferably, the layer is folded into contact with the remaining layers of the composite pipe to inhibit delamination of the layers from fluid leakage through the end of the pipe. Any layer or layers of the composite pipe can be used to form the integral seal. It is preferable, however, for the innermost layer of the composite pipe to be used to create the integral seal. In this manner, a substantial portion of the radially extending surface of the pipe end is enclosed by the integral seal. Alternatively, the outermost layer of the composite pipe can be utilized to create the integral seal. In this case, the outermost layer can be folded radially inward to form the integral seal. 
     In accordance with a method of coupling a connector to a composite pipe of the present invention, the integral seal can be formed by removing the outer layers of the composite pipe at the end of the pipe to expose a portion of an inner layer of the composite pipe. The exposed portion of the inner layer can be heated until the material forming the layer becomes pliable. The exposed portion can then be folded such that the outer surface of the layer engages the ends of the outer layers of the pipe. The inner surface of the folded layer provides the seal surface of the integral seal. Additionally, the ends of the outer layers of the composite pipe can be heated so that the folded layer can coalesce or bond with the ends of the outer layers. The connector is attached to composite pipe and engages the seal surface of the integral seal in a sealing relationship. 
     In accordance with one embodiment of the present invention, the double seal carrier of the pipe-to-pipe connector of the present invention can be replaced by integral seals formed at the end of the first composite pipe and the end of the second composite pipe. The integral seals can be created as discussed above, by radially folding a layer of the composite pipe at the end of the pipe to create a seal surface for engaging a service end. The integral seal of the first composite pipe can be bonded or welded to the integral seal of the second composite pipe to provide an enhanced fluid seal between the ends of the pipes. Alternatively, a gasket can be interposed between the integral seals to improve the fluid seal between the ends of the pipes. 
     A connector for attaching a composite pipe to a service member according to the teachings of the present invention includes a service end, a slip nut disposed about the outer surface of the composite pipe and engageable with the service end, and a slip positioned about the outer surface of the pipe and engaged by the service end and the slip nut. Progressive engagement of the service end relative to the slip nut radially compresses the slip into gripping contact with the pipe. The service end includes an integral seal carrier having a seal thereon to seal between the pipe bore and the service end. The integral seal carrier is positioned within the bore of the pipe when the end connector is coupled to the composite pipe. Preferably, the integral seal carrier is positioned in the pipe bore at a location radially opposite the slip to resist deformation of the pipe when the slip is compressed into gripping contact with the pipe. 
     In contrast to the conventional connectors, the connector of the of the present invention does not require a separate seal carrier or a separate load support member. Instead, the service end provides an integral seal carrier to establish a seal between the pipe bore while concomitantly resisting deformation of the pipe from the radially compressive forces applied by the slip. Preferably, the service end including the integral seal carrier is of single piece, unitary construction. In addition, the seal member or seal members carried by the integral seal carrier can also be positioned radially opposite the slip. In this arrangement, the radially compressive force from the slip can operate to enhance the sealing relationship between the seal members and the interior of the pipe. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of the present invention will be more fully understood by reference to the following detailed description in conjunction with the attached drawings in which like reference numerals refer to like elements through the different views. The drawings illustrate principles of the invention and, although not to scale, show relative dimensions. 
         FIG. 1  is a cross-sectional, elevational view of an end connector assembly for use with a composite tube and embodying principals of the present invention; 
         FIG. 2  shows a cross-sectional perspective, view of an embodiment of a toothed slip used in the connector of  FIG. 1  for engaging the connector body to the composite tube; 
         FIG. 3  shows a partial end view of another embodiment of the toothed slip, showing the configuration of teeth for engaging the composite material in a tubular member receiving the connector; 
         FIG. 4  is a detailed, elevational view of the slip teeth shown in  FIG. 3 ; 
         FIG. 5  is a perspective view in cross-section of an alternative embodiment of the end connector of the present invention, illustrating the end connector coupled to the end of a composite pipe; 
         FIG. 6  is a side elevational view in cross-section of the end connector of  FIG. 5 ; 
         FIG. 7A  is a perspective view of the service end of the end connector of  FIG. 5 ; 
         FIG. 7B  is a side elevational view in cross-section of the service end of  FIG. 7A ; 
         FIG. 8  is a side elevational view in cross-section of the slip nut of the end connector of  FIG. 5 ; 
         FIG. 9A  is a perspective view of the seal carrier of the end connector of  FIG. 5 ; 
         FIG. 9B  is a side elevational view in cross-section of the seal carrier of  FIG. 9A ; 
         FIG. 10A  is a perspective view of the slip of the end connector of  FIG. 5 ; 
         FIG. 10B  is a side elevational view in cross section of the slip of  FIG. 10A ; 
         FIG. 10C  is a detailed elevational view of the teeth of the slip of  FIG. 10A ; 
         FIG. 11  is a perspective view in cross-section of a pipe-to-pipe connector in accordance with the teachings of the present invention, illustrating the connector coupling two composite pipes; 
         FIG. 12  is a side elevational view in cross section of the pipe-to-pipe connector of  FIG. 12 ; 
         FIG. 13A  is a perspective view of the double seal carrier of the pipe-to-pipe connector of  FIG. 11 ; 
         FIG. 13B  is a side elevational view in cross-section of the double seal carrier of  FIG. 13A ; 
         FIG. 13C  is a side elevational view in cross-section of an alternative embodiment of the double seal carrier of  FIG. 13A , illustrating raised ridges formed on the double seal carrier; 
         FIG. 14  is a perspective view of an alternative embodiment of the end connector of the present invention, illustrating the end connector coupled to a composite pipe; 
         FIG. 15  is a side elevational view in cross-section of the end connector of  FIG. 15 ; 
         FIG. 16  is a partially exploded, perspective view of an alternative embodiment of the pipe-to-pipe connector of the present invention; 
         FIG. 17  is a partially exploded, side elevational view in cross-section of the pipe-to-pipe connector of  FIG. 16 ; 
         FIG. 18  is a partially exploded, perspective view of a further alternative embodiment of the pipe-to-pipe connector of the present invention; 
         FIG. 19  is a partially exploded, side elevational view in cross-section of the pipe-to-pipe connector of  FIG. 18 ; 
         FIG. 20  is a side elevational view in cross-section of a service end of a connector of the present invention, illustrating an energy conductor embedded in the service end in accordance with the teachings of the present invention; 
         FIG. 21  is a side elevational view in cross-section of a seal carrier of a connector of the present invention, illustrating raised annular ridges formed on the seal carrier in accordance with the teachings of the present invention; and 
         FIG. 22  is a side elevational view in cross-section of a double seal carrier of a pipe-to-pipe connector of the present invention, illustrating an energy conductor embedded in the double seal carrier in accordance with the teachings of the present invention. 
         FIG. 23  is a perspective view in cross-section of the end connector of the present invention, illustrating the end connector coupled to the end of a composite pipe; 
         FIG. 24  is a side elevational view in cross-section of the end connector of  FIG. 23 ; 
         FIG. 25  is a side elevational view of the service end of the end connector of  FIG. 23 ; 
         FIG. 26  is a side elevational view in cross-section of the service end of  FIG. 25 ; 
         FIG. 27  is a perspective view of the slip nut of the end connector of  FIG. 23 ; 
         FIG. 28  is a side elevational view in cross-section of the slip nut of  FIG. 27 ; 
         FIGS. 29A and 29B  are perspective views of the slip of the end connector of  FIG. 23 ; 
         FIG. 30  is a side elevational view in cross section of the slip of  FIGS. 29A ,  29 B; 
         FIG. 31  is a detailed elevational view of the teeth of the slip of  FIGS. 29A ,  29 B; 
         FIG. 32  is a side elevational view in cross-section of an alternative embodiment of the service end of a connector of the present invention, illustrating an energy conductor embedded in the service end in accordance with the teachings of the present invention; and 
         FIGS. 33A and 33B  are side elevational views in cross-section of an alternative embodiment of the service end of an end connector of the present invention, illustrating raised annular ridges formed on the service end in accordance with the teachings of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While this invention is directed generally to providing connectors for composite spoolable pipe, the disclosure is directed to a specific application involving line pipe, coiled tubing service and downhole uses of coiled tubing. Composite coiled tubing offers the potential to exceed the performance limitations of isotropic metals, thereby increasing the service life of the pipe and extending operational parameters. Composite coiled tubing is constructed as a continuous tube fabricated generally from non-metallic materials to provide high body strength and wear resistance. This tubing can be tailored to exhibit unique characteristics which optimally address burst and collapse pressures, pull and compression loads, as well as high strains imposed by bending. This enabling capability expands the performance parameters beyond the physical limitations of steel or alternative isotropic material tubulars. In addition, the fibers and resins used in composite coiled tubing construction make the tube impervious to corrosion and resistant to chemicals used in treatment of oil and gas wells. 
     High performance composite structures are generally constructed as a buildup of laminant layers with the fibers in each layer oriented in a particular direction or directions. These fibers are normally locked into a preferred orientation by a surrounding matrix material. The matrix material, normally much weaker than the fibers, serves the critical role of transferring load into the fibers. Fibers having a high potential for application in constructing composite pipe include glass, carbon, and aramid. Epoxy or thermoplastic resins are good candidates for the matrix material. 
     The connector of the present invention can have application to any number of composite tube designs but is arranged to be applied to a pipe having an outer surface made from a composite material that can receive gripping elements which can penetrate into the composite material without destroying the structural integrity of the outer surface. This outer surface can act as a wear surface as the pipe engages the surface equipment utilized in handling such pipe. The composite pipe is suitable for use in wellbores or as line pipe. 
     Referring to  FIG. 1 , an end connector assembly is shown having a service end  31  having a threaded end portion  33  for connection to other devices or components in a bottom hole assembly, or to connect to other lengths of spoolable pipe. A slip nut  35  has an internally threaded end portion  36  for engagement with external threads on a trailing end  37  of the service end  31 . A bevel  39  is formed in the bore of the trailing end  37  to form a reverse load flank. A beveled surface  41  is also formed in the bore of the slip nut  35 . The beveled surfaces  39 ,  41  together form a cavity when the slip nut  35  and service end  31  are threadedly engaged as shown in  FIG. 1 . This cavity is shaped to receive and matingly engage the oppositely beveled outer surfaces formed on a splined tooth load slip  45 . Other components of the connector assembly comprise a seal carrier  47  and a slip load support  49  that is arranged, in assembly, within the bore of the composite pipe  15 . 
     When assembled, the bore of slip nut  35  is slid up over the outer surface of the pipe  15  well back from the service end of the pipe. The slip load support  49  is then positioned in the bore of pipe  15  at a spaced distance from the end of the pipe which is calculated to be opposite the cavity in the connector assembly receiving the slip  45 . Next the slip  45  is positioned about the outer surface of the composite pipe opposite the position of the load support  49 . The seal carrier  47  together with seals  51 ,  52  on the outer surface of the carrier and seat ring  53  positioned against shoulder  55 , are assembled into and against the end of the composite coiled tubing. The seat ring may be constructed of a material such as Nitrile, Viton or Teflon. The seal ring  53  can be constructed of a material having a hardness of 80° to 100° durometer. The seals  51  and  52  seal off the space between the outer surface of the carrier  47  and the bore of the tubing  15 . Sealing between the bore of composite pipe  15  and the connector provides the advantage of sealing to a more accurately dimensioned and regular surface, to thereby enhance sealing performance. The seat ring  53  seals off and protects the end of the tubing  15 . In addition all these seals are removable and replaceable by removing the carrier from the end of the tubing  15 . This can be done without disturbing the load transfer mechanism of the connector, i.e. the slip system. 
     The service end  31  is then inserted over the end of the tubing  15  and an outer end portion  56  of carrier  47  projecting out of the end of tubing  15 . A rubber seal  54  is positioned on this projecting end portion  56  to seal between the carrier  47  and the bore of service end  31 . When the carrier  47  is inserted into the bore of tubing  15 , its length is sized to engage the slip load support  49  and move it into the proper position within the tubing to be opposite the slip  45 . The last step in the assembly is to move the slip nut  35  forward on the tubing until it can be threadedly made up onto the threaded trailing end  37  of the service end  31 . As this threaded connection is made up, the tapered surface  39  on the trailing end  37  and a similar beveled undercut  41  on the bore of slip nut  35  engage respective surfaces  57 ,  58  of a double tapered outer surface of the slip  45 . This engaging action of surfaces  57 ,  58  on the slip  45  with the beveled surfaces  39  and  41  serves to compress the slip teeth into the outer surface of the tubing  15 . 
       FIGS. 2-4  show the slip  45  in detail having the longitudinally oppositely tapered surfaces  57 ,  58  on its outer surface. A longitudinal slot  61 , shown in  FIG. 2 , provides a means for collapsing or compressing the slip  45  about the pipe  15  and thereby embed the slip teeth into the outer layer(s) of the composite pipe. The teeth have a laterally flat top edge  63  and a laterally flat spacing  65  between longitudinal rows of teeth. A sloping surface  67  of the teeth tapers from an outward edge  63  to a flat valley  69  between lateral or circumferential rows of teeth. The teeth can be arranged in substantially longitudinal rows that are circumferentially spaced 10° to 20° from one another, and the rows of teeth can be separated by a flat bottomed furrow each having a width of at least 0.09 inches. The distance between parallel circumferential rows can be from 0.08 to 0.12 inches. These teeth, as contrasted to spiral threads used on steel tube applications are arranged to fully embed into the outer surface so that the valley surface  69  on the toothed slip is in contact with the material in the outer layers and the entire tooth surface area is engaged with material in the composite pipe layers. It is preferable that the teeth penetrate into the laminate of fibers and encompassing resin in the composite tube to provide the shear strength needed to ensure adequate tensile load strength. The top flat edge  63  is likewise arranged to provide a firm and extensive lateral surface on the teeth to give tensile strength to the load transfer system. 
     The longitudinal flat spiral furrow  65 , between rows of teeth, serves to provide a frictional engaging surface between the slip and the pipe&#39;s outer surface to further enhance the load transfer factor between the connector and the pipe. The width of this furrow surface  65  may be in the range of 0.110 to 0.120 inches for a slip used with 1½ inches OD composite pipe. This represents a total furrow  65  cross-sectional surface that is greater than 50% of the circumference measurement on the inner toothed surface of the slip. 
     The service to which a coiled tubing string is subjected provides a rather severe physical environment. Internal pressures may be in the order of 7,000 to 10,000 psi; while tensile loads can be as much as 20,000 to 25,000 psi. With this in mind it is readily seen that load transfer between a connector and the composite pipe is of critical importance and features such as those described in the present application, as for example in the shape and spacing of teeth on the slip, become extremely important to the overall success of this new product. 
     An alternative embodiment of the end connector of the present invention is illustrated in  FIGS. 5-10C . The end connector  100  provides for the attachment of a composite pipe  102  to a service member (not shown), such as a logging tool, or t-fitting in a pipeline. The composite pipe  102  includes at least one composite layer  104  of fibers embedded in a polymer matrix and preferably includes a substantially fluid impervious interior liner  106  disposed concentrically within the composite layer  104 . Although only one composite layer is illustrated and described herein, one skilled in the art will appreciate that the composite pipe  102  can include multiple composite layers depending on the application and service in which the composite pipe is to be used. The principal components of the end connector  100  include a service end  108 , a slip  110 , a slip nut  112 , and a seal carrier  114 . 
     Referring to  FIGS. 5-7B , the service end  108  includes a first coupling surface  116  at one end thereof for connecting the pipe  102  with a service member and a second coupling surface  118  the other end thereof for connecting the service end  108  with the slip nut  112  and thereby assembling the service end  108  to the pipe  102 . The first and second coupling surfaces  116  and  118  can be threaded as illustrated or can be provided with alternative mechanisms for attaching the service end to the service member or the pipe. The service end  108  includes a generally conically tapered, tubular housing bore  122  sized and shaped to receive an end of the seal carrier  114 . The housing bore  122  tapers from an increased diameter at the second coupling surface  118  to a reduced diameter at the first coupling surface  116 . 
     Referring to  FIGS. 5 ,  6 , and  10 A- 10 B, the slip  110  is generally cylindrical in shape and is sized to fit about the outer surface of the composite pipe  102 . The slip  110  includes a tapered outer surface  124  that tapers from an increased diameter at a distal end  126  to a reduced diameter at a distal end  128 . A longitudinal slot  129  is formed in the slip  110  to permit radially compression of the slip. The slip  110  can also be formed in multiple sections to permit radial compression. Pipe-engaging teeth  130  are formed on the inner surface of the slip  110 . The teeth  130  are sized and shaped to fully embed into the outer surface of the composite pipe  102 . The teeth  130  are arranged in longitudinally or helically spaced rows. Each row includes a generally radially extending surface  132  that intersects with an angled surface  134  to form a sharp point  136 , as best illustrated in  FIG. 10C . Preferably, the entire surface of each tooth, i.e. the radially extending surface  132  and the angled surface  134 , is engaged with the fibers and the polymer resin forming the composite layer  104  of the pipe  102 . In this manner, the teeth  130  permit the transfer of loads into the composite layer  104  of the composite pipe  102 . 
     Alternatively, the slip  110  can be provided with teeth sized, shaped, and arranged in a manner analogous to the teeth of the slip  45  of the first embodiment of the present invention, as described above. 
     Continuing to refer to  FIGS. 5 and 6 , and referring specifically to  FIG. 8 , the slip nut  112  is generally cylindrical in shape and is provided with a threaded coupling surface  136  formed on the inner surface thereof. The inner bore  138  of the slip nut  112  includes a centrally located tapered surface  140  for engaging the outer surface  124  of the slip  110  when the end connector  100  is coupled to the pipe  102 . The inner bore  138  is sized to permit the slip nut  112  to be positioned about the outer surface of the composite pipe  102 . 
     The seal carrier  114  is generally cylindrical in shape and is preferably of single piece, unitary construction. The seal carrier  114  is sized to be received within the bore of the composite pipe  102  and the housing bore  112  of the service end  108 , as shown in  FIGS. 5 ,  6 , and  9 A- 9 B. Annular grooves  142  and  144  are formed in the outer surface of the seal carrier  114  to receive seal members  145 , such as elastomeric O-rings, for providing a seal between the seal carrier  114  and the composite pipe  102 . One skilled in the art will recognize that additional seal members or a single seal member may be used depending on the integrity of the fluid seal desired. An annular, raised shoulder  146  extends radially outward from the outer surface of the seal carrier  114 . The annular shoulder  146  engages a radially inward extending surface  148  ( FIG. 7B ) of the service end  108  when the end connector  100  is coupled to the composite pipe  102 . 
     An alternative embodiment of the seal carrier  414  is illustrated in  FIG. 21 , in which the annular grooves and the seal members are replaced with raised, barb-like, ridges  420 . The ridges  420  can be generally triangular in cross-section to form a sharpened point for embedding into the inner layer, such as the interior liner, of the composite pipe. The ridges  420  can also have other cross-sectional shapes sufficient for the ridges to embed in the inner layer of the composite pipe. The ridges  420  can also be spiral or circular oriented threads. The seal member  414  also includes an annular shoulder  446  for abutting the end of the composite pipe. The raised ridges  420  eliminate the need for separate seal members, which can wear during use resulting in fluid leakage. Also, because grooves need not be formed in the seal carrier, the thickness of the wall  422  of the seal carrier, indicated by arrow t in  FIG. 21 , can be reduced. This reduction in thickness allows the seal carrier inner diameter to more closely match the inner diameter of the composite pipe thereby minimizing flow disruptions and turbulence of the fluid within the pipe at the interface of the seal carrier and the composite pipe. 
     Each of the components of the end connector  100 , namely the service end  108 , the slip  110 , the slip nut  112  and the seal carrier  114  (or seal carrier  414 ) can be constructed from either metallic materials, composite materials, thermoplastics, elastomers, or combinations thereof. 
     When assembled, the slip nut  112  is slid over the outer surface of the composite pipe  102 . The slip  110  is positioned about the composite pipe  102  and within a recess formed between the outer surface of the pipe and tapered surface  140  of the slip nut  112 . The seal carrier  114  is positioned within the bore of the composite pipe  102  such that the shoulder  146  abuts the end of the composite pipe  102 . The service end  108  is inserted over the end of the seal carrier  114  such that radial surface  148  of the service end  108  engages the annular shoulder  146  of the seal carrier  114 . The slip nut  112  is coupled to the service end  108  by threaded engagement of the second coupling surface  118  and the threaded coupling surface  136  of the slip nut. During coupling, the service end  108  and the slip nut  112  move axially towards one another and the tapered surface  140  of the connector engages the tapered outer surface  124  of the slip  110 . Once the distal end  126  of the slip  110  abuts the end of the service end  108 , as best illustrated in  FIG. 6 , the engaging action of the tapered surface  140  on the slip  110  acts to radially compress the teeth  130  of the slip  110  into engagement with the outer surface of the composite pipe  102 . 
     Preferably, the seal carrier  114  is positioned such that the annular groves  142  and  142 , and the seal members  145  are positioned radially opposite the slip  110  when the end connector  100  is coupled to the composite pipe  102 , as illustrated in  FIGS. 6 and 7 . By positioning the seal carrier  114  in this manner, the seal carrier  114  can establish a fluid seal with the bore of the composite pipe  102  while concomitantly resisting deformation of the pipe from the radially compressive forces applied by the slip  110 . Thus, in contrast to the connector embodiments described above, the end connector  100  does not require a separate load support member to inhibit deformation of the composite pipe  102 . The seal carrier  114  provides this function. Additionally, in this arrangement, the radially compressive force from the slip  110  can operate to increase the sealing relationship between the seal members  145  and the bore of the composite pipe  102 . 
     A connector  200  for establishing a pipe-to-pipe connection between a first composite pipe  202 A and a second composite pipe  202 B is shown in  FIGS. 11 and 12 . The pipe-to-pipe connector includes a service end  204  having a coupling surface  206  in the form of threads formed on the outer of the first service end  204  and the outer surface of the composite pipe. The first service end  204  includes a housing bore  208  for receiving an end of the first composite pipe  202 A. A first slip  210 A is positioned about the outer surface of the first composite pipe  202 A and is received within a recess formed by a conically tapered surface  209  of the first service end  204 . The first slip  210 A can be sized and shaped in a manner analogous to the slip  110  of the end connector  100  or the slip  45 , both of which are described above. In this regard, the first slip  110  preferably includes teeth sized, shaped, and arranged to penetrate and embed into the first composite pipe  202 A. 
     A slip nut  212  includes a bore  214  for receiving an end of the second composite pipe  202 B and has a second coupling surface  216  in the form of threads formed on the inner surface of the bore  214 . The second coupling surface  216  is configured to matingly engage the first coupling surface  206  of service end  204 . As discussed above, alternative attachment mechanisms can be employed in place of the first and second thread surfaces  206 ,  216 . A second slip  210 B is positioned about the outer surface of the second composite pipe  202 B and is received within a recess formed by a conically tapered surface  216  of the slip nut  212  and the outer surface of the composite pipe. The second slip  210 B, like the first slip  210 A, can be sized and shaped in a manner analogous to the slip  110  of the end connector  100  or the slip  45 , described above. In this regard, the second slip  210 B includes teeth sized, shaped, and arranged to penetrate and embed into the second composite pipe  202 B. 
     Continuing to refer to  FIGS. 11 and 12 , and in particular to  FIGS. 13A and 13B , a double seal carrier  220  is positioned within the end of the first composite pipe  202 A and the end of the second composite pipe  202 B. The double seal carrier  220  is preferably of single piece, unitary construction and is generally tubular in shape. The double seal carrier  220  includes a raised annular shoulder  222  having a first radially extending surface  224  for axially engaging the end of the first composite pipe  202 A and a second radially extending surface  226  for axially engaging the end of the second composite pipe  202 B. Annular grooves  228 A,  228 B,  228 C, and  228 D are formed in the outer surface of the seal carrier  220  and are sized and shaped to receive seal members  229 , such as elastomeric O-rings. The seal members  229  sealingly engage the inner surface of the first composite pipe and the inner surface of the second composite pipe to provide a fluid seal between the double seal carrier  220  and both the first composite pipe  202 A and the second composite pipe  202 B. 
     Alternatively, the annular grooves and the seal members of the double seal carrier  220  can be replaced with raised, barb-like replaced with raised, barb-like, ridges  520 , as illustrated in  FIG. 13C . The ridges  520  can be generally triangular in cross-section to form a sharpened point for embedding into the inner layer, such as the interior liner, of the composite pipe. The ridges  520  can also have other cross-sectional shapes sufficient for the ridges to embed in the inner layer of the composite pipe. The ridges  520  can also be spiral or circular oriented threads. The raised ridges  520  eliminate the need for separate seal members, which can wear during use resulting in fluid leakage. Also, because grooves need not be formed in the seal carrier, the thickness of the wall of the double seal carrier can be reduced. This reduction in thickness allows the seal carrier inner diameter to more closely match the inner diameter of the composite pipes thereby minimizing flow disruptions and turbulence of the fluid within the pipes at the interface of the double seal carrier and the composite pipes. 
     In assembly, the service end  204  is positioned about the end of the first composite pipe  202 A and the slip nut  212  is positioned about the end of the second composite pipe  202 B. The first slip  210 A is positioned about the first composite pipe  202 A and within the recess of the service end  204 . Likewise, the second slip  210 B is positioned about the second composite pipe  202 B and within the recess of the slip nut  212 . The double seal carrier  220  is then positioned within the end of the first composite pipe  202 A and within the end of the second composite pipe  202 B such that the first radially extending surface  224  of the shoulder  222  axially abuts the end of the first composite pipe  202 A and a second radially extending surface  226  of the shoulder  222  axial abuts the end of the second composite pipe  202 B. The service end  204  is then coupled to the slip nut  212 . As the service end  204  and the slip nut  212  are drawn together axially, the conically tapered surface  209  and the conically tapered surface  216  engage the first and second slips  210 A,  210 B, respectively, to radially compress the teeth of the slips into engagement with the outer surface of the composite pipes. 
     Preferably, the double seal carrier  220  is positioned such that annular grooves  228 A and  228 B, and the seal members  229  carried therein, are positioned radially opposite the first slip  210 A. Likewise, it is preferable for the annular grooves  228 C and  228 D, and the seal members  229  carried therein, to be positioned radially opposite the second slip  210 B. By positioning the double seal carrier  220  in this manner, the double seal carrier can establish a fluid seal with the inner surface of the composite pipe  202 A and the inner surface of the composite pipe  202 B, while concomitantly resisting deformation of both pipes from the radially compressive forces applied by the slips. 
     Each of the components of the connector  200 , namely the service end  204 , the first slip  210 A, the slip nut  212 , the second slip  210 B, and the double seal carrier  220 , can be constructed from either metallic materials, composite materials, thermoplastic materials, elastomers, or combinations thereof. 
       FIGS. 14 and 15  illustrate an alternative embodiment of the end connector of the present invention. The end connector  300  includes similar components as the end connector  100  illustrated in  FIGS. 5-10C , namely a service end  108 , a slip  110 , and a slip nut  112 . The end connector  300 , however, does not require a seal carrier to provide a fluid seal between the end connector and the composite pipe. Instead, a generally annular, integral seal  302  is positioned at the end of the composite pipe  102  to provide the primary fluid seal between the service end  108  and the composite pipe  102 . 
     The integral seal  302  is formed by folding a portion of the interior liner  106  of the composite pipe  102  radially outward. In this manner, a radially extending first seal surface  304  is formed for engaging a radially extending surface  306  of the service end  108  in a sealing relationship. A gasket  308  can be interposed between the first seal surface  304  and the surface  306  of the service end  108  to enhance the seal. The integral seal  302  also includes a second radially extending surface  310  that contacts and seals the end of the composite layer  104 . 
     The annular seal  302  can be formed by removing the outer layers of the composite pipe  102 , such as composite layer  104 , to expose a portion of the interior liner  106  at the end of the pipe. The exposed portion of the liner  106  can then be heated until the liner becomes pliable. In the case of a liner formed from a polymer material, such as a thermoplastic, the liner can be heated to a softening temperature which is less than the melt temperature of the thermoplastic. Once pliable, the exposed portion of the liner can be folded to form the integral seal  302 . By heating the end of the composite layer  104 , the integral seal  302  can coalesce with the polymer matrix of the composite layer  104  to provide a fluid impervious connection between surface  310  of the integral seal  302  and the end of the composite layer  104 . 
     The integral seal  302  can be formed from layers other than the interior liner  106  of the composite pipe. Any layer, including any composite layers, can be folded radially outward to form the seal  302 . Alternatively, an outer layer of the composite pipe can be folded radially inward to form the integral seal  302 . To provide the most effective seal, however, it is preferable for the either innermost or the outermost layer of the composite pipe to be used. In this manner delamination of any exposed layers of the pipe, i.e., layers not encompassed by the integral seal, will be inhibited. 
     Moreover, the integral seal  302  need not be formed with a radially extending seal surface  304 . The seal surface  304 , as well as the mating surface  306  of the service end, can be oriented at angles other than perpendicular to the longitudinal axis of the composite pipe. The seal surface  304  can be any angle from 0° to 180° relative to the longitudinal axis of the composite pipe. 
     An alternative embodiment of the pipe-to-pipe connector of the present invention is illustrated in  FIGS. 16 and 17 . The pipe-to-pipe connector  400  includes similar components as the pipe-to-pipe connector  200  illustrated in  FIGS. 11 and 12 , namely, a service end  204 , a first slip  210 A, a slip nut  212 , and a second slip  210 B. Connector  400  does not, however, require a double seal carrier to provide a fluid seal between the first and second composite pipes. Instead, first and second integral seals  402 A and  402 B are provided at the respective ends of the first and second composite pipes  202 A and  202 B to provide fluid seals between the composite pipes. 
     The integral seals  402 A and  402 B can be formed in a manner analogous to integral seal  302 , described above. A layer of the composite pipe can folded radially outward or inward to provide a sealing surface. The first integral seal  402 A has a radially extending first seal surface  404 A. The second integral seal  402 B has a radially extending second seal surface  404 B. 
     Prior to assembly of the pipe ends, the integral seals  402 A and  402 B can be bonded or welded together by heating and joining the first and second seal surfaces such that the first seal surface  404 A coalesces with the second seal surface  404 B. In this manner a fluid impervious seal can be established between the first and second composite pipes. A reinforcing ring  406  can be provided at the interface between the first seal surface  404 A and the second seal surface  404 B to inhibit radial separation of the seal surfaces due to internal fluid pressure within the composite pipes. 
     It is not, however, necessary for the first integral seal  402 A to be bonded or welded to the second integral seal  402 B to provide an effective fluid seal between the integral seals. The mating engagement of the service end  204  and the slip nut  212 , together with the radial compressive force provided by the first and second slips  210 A and  210 B, can be sufficient to maintain the first and second sealing surfaces  404 A and  404 B in a sealing relationship. In addition a gasket can be provided between the integral seals  402 A and  402 B to improve the effectiveness of the fluid seal at the interface of the integral seals. 
     A further alternative embodiment of the pipe-to-pipe connector of the present invention is illustrated in  FIGS. 18 and 19 . The pipe-to-pipe connector  450  includes similar components as the pipe-to-pipe connector  200  illustrated in  FIGS. 11 and 12 , namely, a service end  204 , a first slip  210 A, a slip nut  212 , and a second slip  210 B. Connector  450  does not, however, require a double seal carrier to provide a fluid seal between the first and second composite pipes. Instead, the end  454 A of the first composite pipe  202 A and the end  454 B of the second composite pipes  202 B provide the fluid seal between the composite pipes. 
     The composite pipe ends  454 A and  454 B are preferably formed such that the end of each layer forming the composite pipe is flush, i.e., the ends of the layers cooperatively form a continuous planar surface. In this manner, the ends  454 A and  454 B can provide effective sealing surfaces with which to join the composite pipes. 
     Prior to assembly of the pipe ends, the composite pipe ends  454 A and  454 B can be bonded or welded together by heating and joining the ends such that the first end  454 A coalesces with the second end  454 B. In this manner a fluid impervious seal can be established between the first and second composite pipes. A reinforcing ring  406  can be provided at the interface between the first seal surface  404 A and the second seal surface  404 B to inhibit radial separation of the seal surfaces due to internal fluid pressure within the composite pipes. 
     It is not, however, necessary for the first end  454 A to be bonded or welded to the second integral seal  454 B to provide an effective fluid seal between the composite pipes. The mating engagement of the service end  204  and the slip nut  212 , together with the radial compressive force provided by the first and second slips  210 A and  210 B, can be sufficient to maintain the first and second composite pipe ends  454 A and  454 B in a sealing relationship. In addition, a gasket  452  can be provided between the ends  454 A and  454 B to improve the effectiveness of the fluid seal at the interface of the composite pipes. 
     Each of the connector embodiments described herein can also include one or more energy conductors to permit connection of energy conductors mounted within the composite pipe to the energy conductors of a service member or the energy conductors of another composite pipe. For example,  FIG. 20  illustrates the service end  108  of the end connector illustrated in  FIG. 5  including an energy conductor  500  embedded within, i.e. surrounded by a material of, the service end  108 .  FIG. 22  illustrates an energy conductor  500  embedded in the annular shoulder  222  of a double seal carrier  220  for a pipe-to-pipe connector. The energy conductor  500  can be an electric medium, such as a copper wire, an optical medium, such as an optical fiber, a hydraulic medium, a pneumatic medium or any material or substance capable of being modulated with data signals or power. The energy conductor  500  provides structure to connect the energy conductors of the composite pipe to the energy conductors of a service member, in the case of an end connector, or the energy conductors of another composite pipe, in the case of a pipe-to-pipe connector. Composite pipes including energy conductors are described in commonly assigned U.S. Pat. No. 5,921,285 and commonly assigned U.S. No. 6,004,639, each of which are expressly incorporated by reference herein in their entireties. 
     Referring to  FIGS. 23 and 24 , an end connector  2010  according to the present invention provides for the attachment of a composite pipe  2012  to a service member (not shown), such as a logging tool, or t-fitting in a pipeline. The composite pipe  2012  includes at least one composite layer  2014  of fibers embedded in a polymer matrix and preferably includes a substantially fluid impervious interior liner  2016  disposed concentrically within the composite layer  2014 . Although only one composite layer is illustrated and described herein, one skilled in the art will appreciate that the composite pipe  2012  can include multiple composite layers depending on the application and service in which the composite pipe is to be used. The principal components of the end connector  2010  include a service end  2018 , a slip  2020 , and a slip nut  2022 . 
     Referring to  FIGS. 23-26 , the service end  2018  includes a first coupling surface  2026  at a first end  2024  thereof for connecting the pipe  2012  with a service member and a second coupling surface  2028  proximate the midpoint between the first end  2024  and the second end  2030  of the service end  2018 . The second coupling surface  2028  provides for the connection of the service end  2018  with the slip nut  2022  and, thus, the assembly of the service end  2018  to the pipe  2012 . The first and second coupling surfaces  2026  and  2028  can be threaded as illustrated or can be provided with alternative mechanisms for attaching the service end to the service member or the pipe. The service end  2018  includes a generally tubular housing bore  2031  having an inner diameter that is preferably equal to, or slightly less than, the inner diameter of the composite pipe  2012 . 
     The second end  2030  of the service end  2018  includes an integral seal carrier  2032 . The integral seal carrier  2032  is generally cylindrical in shape and is sized to be received within the bore of the composite pipe  2012 , as shown in  FIGS. 23 and 24 . Preferably, the outer diameter of the integral seal carrier  2032  is equal to, or slightly less than, the inner diameter of the composite pipe  2012  such that the integral seal carrier  2032  can be received within the bore of the composite pipe  2012  in a substantially friction-tight fit. Annular grooves  2034  are formed in the outer surface of the seal carrier  2032  to receive seal members  2036 , such as elastomeric O-rings, for providing a seal between the integral seal carrier  2032  and the composite pipe  2012 . One skilled in the art will recognize that additional seal members or a single seal member may be used depending on the integrity of the fluid seal desired. A radially extending surface  2038  extends radially outward from the outer surface of the seal carrier  2032  to form an annular shoulder for engaging the end of the composite pipe  2012 , as well as an end of the slip  2020 , when the end connector  2010  is coupled to the composite pipe  2012 . 
     The service end  2018 , including the integral seal carrier  2032 , is preferably of single piece, unitary construction. A significant advantage of the end connector of the present invention is that, unlike conventional end connectors, the end connector  2010  of the of the present invention does not require are separate, discrete seal carrier to provide a fluid seal between the end connector and the composite pipe and/or a separate load support member to inhibit deformation of the composite pipe  2012  from the slip  2020 . The service end  2018 , including the integral seal carrier  2032 , provides both of these functions. 
     Referring to  FIGS. 23 ,  24 , and  29 A- 31 , the slip  2020  is generally cylindrical in shape and is sized to fit about the outer surface of the composite pipe  2012 . The slip  2020  includes a tapered outer surface  2040  that tapers from an increased diameter at a first end  2044  to a reduced diameter at a second end  2046 . A longitudinal slot  2042  is formed in the slip  2020  to permit radial compression of the slip  2020 . The slip  2020  can also be formed in multiple sections to permit radial compression. Pipe-engaging teeth  2050  are formed on the inner surface of the slip  2020 . The teeth  2050  are sized and shaped to fully embed into the outer surface of the composite pipe  2012 . The teeth  2050  can be arranged in longitudinally, circumferentially, and/or helically spaced rows. In one preferred embodiment, illustrated in  FIG. 29B , the teeth are arranged in helically spaced rows oriented at approximately 45° to the longitudinal axis of the composite pipe. Applicants determined that this particular orientation of the teeth provides increased resistance to external torque exerted on the connector. 
     Each row of teeth preferably includes a generally radially extending surface  2052  that intersects with an angled surface  2054  to form a sharp point  2056 , as best illustrated in  FIG. 31 . Preferably, the entire surface of each tooth, i.e. the radially extending surface  2052  and the angled surface  2054 , is engaged with the fibers and the polymer resin forming the composite layer  2014  of the pipe  2012 . In this manner, the teeth  2050  permit the transfer of loads into the composite layer  2014  of the composite pipe  2012 . 
     Alternatively, the slip  2020  can be provided with teeth sized, shaped, and arranged in a manner analogous to the teeth of the slip of the end connector described in commonly-assigned U.S. Pat. No. 5,988,702, expressly incorporated by reference herein in its entirety. 
     Continuing to refer to  FIGS. 23 and 24 , and referring specifically to  FIGS. 27 and 28 , the slip nut  2022  is generally cylindrical in shape and is provided with a threaded coupling surface  2060  formed on the inner surface thereof. The inner bore  2064  of the slip nut  2022  includes a centrally located tapered surface  2062  for engaging the outer surface  2040  of the slip  2020  when the end connector  2010  is coupled to the pipe  2012 . The inner bore  2064  is sized to permit the slip nut  2022  to be positioned about the outer surface of the composite pipe  2012 . 
     Each of the components of the end connector  2010 , namely the service end  2018 , the slip  2020 , and the slip nut  2022  can be constructed from either metallic materials, composite materials, thermoplastics, elastomers, or combinations thereof. In one preferred embodiment, as shown in  FIG. 26 , the components of the end connector  2010 , in particular the service end  2018 , can be constructed of a metallic material  2018   a  coated with a corrosion resistant material  2018   b ,  2018   bb , such as, for example, epoxy. 
     When assembled, the slip nut  2022  is slid over the outer surface of the composite pipe  2012 . The slip  2020  is positioned about the composite pipe  2012  and within a recess formed between the outer surface of the pipe and tapered surface  2062  of the slip nut  2022 . The integral seal carrier  2032  of the service end  2018  is positioned within the bore of the composite pipe  2012  such that the shoulder formed by radially extending surface  2038  abuts the end of the composite pipe  2012 . The slip nut  2022  is coupled to the service end  2018  by threaded engagement of the second coupling surface  2028  and the threaded coupling surface  2060  of the slip nut. During coupling, the service end  2018  and the slip nut  2022  move axially towards one another and the tapered surface  2062  of the slip nut  2022  engages the tapered outer surface  2040  of the slip  2020 . Once the first end  2044  of the slip  2020  abuts the radially extending surface  2038  of the service end  2018 , as best illustrated in  FIG. 24 , the engaging action of the tapered surface  2062  on the slip  2020  acts to radially compress the teeth  2050  of the slip  2020  into engagement with the outer surface of the composite pipe  2012 . 
     Preferably, the service end  2018  is positioned such that the annular groves  2034  of the integral seal carrier  2032 , and the seal members  2036 , are positioned radially opposite the slip  2020  when the end connector  2010  is coupled to the composite pipe  2012 , as illustrated in  FIGS. 23 and 24 . By positioning the integral seal carrier  2032  in this manner, the integral seal carrier  2032  can establish a fluid seal with the bore of the composite pipe  2012  while concomitantly resisting deformation of the pipe from the radially compressive forces applied by the slip  2020 . Thus, in contrast to conventional connector embodiments, the end connector  2010  of the present invention does not require a separate seal carrier to provide a fluid seal or a separate load support member to inhibit deformation of the composite pipe  2012 . The integral seal carrier  2032  of the service end  2018  provides these functions. Additionally, in this arrangement, the radially compressive force from the slip  2020  can operate to increase the sealing relationship between the seal members  2036  and the bore of the composite pipe  2012 . 
     The end connector of the present invention can also include one or more energy conductors to permit connection of energy conductors mounted within the composite pipe to the energy conductors of a service member or the energy conductors of another composite pipe. For example,  FIG. 32  illustrates a service end  2118  including an energy conductor  2170  embedded in, i.e. surrounded by a material of, the service end  2118 . The energy conductor  2170  can be an electric medium, such as a copper wire, an optical medium, such as an optical fiber, a hydraulic medium, a pneumatic medium or any material or substance capable of being modulated with data signals or power. The energy conductor  2170  provides structure to connect the energy conductors of the composite pipe to the energy conductors of a service member. Composite pipes including energy conductors are described in commonly assigned U.S. Pat. No. 5,921,285 and commonly assigned U.S. Pat. No. 6,004,639, each of which are expressly incorporated by reference herein in their entireties. 
     In embodiments, the end connector can include one or more openings or conduits to permit connection of energy conductors mounted within the composite pipe to energy conductors of a service member and/or energy connectors of another composite pipe. The conduits can isolate energy conductors from the environmental conditions (such as pressure and/or temperature) of the interior of the composite pipe. In one such embodiment, the end connector can include a conduit and an energy conductor of a composite pipe can be passed through the conduit to a service member. 
     An alternative embodiment of the service end  2218  is illustrated in  FIGS. 33A-33B , in which the annular grooves and the seal members of the integral seal carrier  2232  are replaced with raised, barb-like, ridges  2280 . The ridges  2280  can be generally triangular in cross-section to form a sharpened point for embedding into the inner layer, such as the interior liner, of the composite pipe. The ridges  2280  can also have other cross-sectional shapes sufficient for the ridges to embed in the inner layer of the composite pipe. The ridges  2280  can alternatively be spiral oriented threads, as shown in  FIG. 33B , or circular oriented threads, as shown in  FIG. 33A . The raised ridges  2280  eliminate the need for separate seal members, which can wear during use resulting in fluid leakage. Also, because grooves need not be formed in the seal carrier, the thickness of the wall  2290  of the integral seal carrier  2232 , indicated by arrow t in  FIGS. 33A ,  33 B, can be reduced. This reduction in thickness allows the inner diameter of the integral seal carrier  2232  to more closely match the inner diameter of the composite pipe thereby minimizing flow disruptions and turbulence of the fluid within the pipe at the interface of the seal carrier and the composite pipe. 
     It should be understood that the component parts of the embodiments of  FIGS. 32 and 33A ,  33 B, respectively, are similar to those previously described herein, and accordingly the same reference numerals are used to designate similar parts although the numerals are incrementally increased by 100 to differentiate the embodiments described herein. 
     While particular embodiments of the present invention have been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.