Patent Publication Number: US-6698514-B2

Title: Remote operated coil connector apparatus

Description:
DESCRIPTION OF THE INVENTION 
     BACKGROUND OF THE INVENTION 
     The invention relates to a remote operated coil connector apparatus for use with coiled tubing in a well bore. 
     The use of coiled tubing as a device for well intervention applications is well known. The use of coiled tubing permits the insertion and withdrawal from a well bore of both mechanical and hydraulic tooling. It is also applicable to the use of electronic devices in the well bore that require an electrical conductor extending from the device to surface facilities. Since various operations are required to be performed in the well bore, which in turn require various tool strings, it is necessary to, in coiled tubing operations, change the tool to accommodate the desired function. This operation is performed manually. For extreme and remote operations, however, such as sub-sea or hazardous operations, manual selection and changing of the tools required is not practical or efficient. 
     It is accordingly an object of the present invention to provide a coil connector apparatus that may be remotely operated from the standpoint of connecting and disconnecting tool strings to accommodate various well bore operations. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, there is provided a remote operated coil connector apparatus for use with coiled tubing in a well bore. The apparatus comprises a coiled tubing connector having at one end thereof connector means for mechanical connection to coiled tubing and at an opposite end thereof a second connector means. There is further provided an upper assembly having at one end thereof connector means for mechanical connection to the second connector means of the coiled tubing connector and said coiled tubing, and at an opposite end thereof second mechanical connector means and electrical connection means. There is further provided a lower assembly having at one end thereof connector means for mechanical connection to the mechanical connection means of the upper assembly and electrical connection means for electrical connection to the electrical connection means of the upper assembly. The lower assembly is also provided at an opposite end thereof second connector means for mechanical connection. Further, there is a tool holder having connection means at an upper end thereof for mechanical connection to the second connector means of the lower assembly and at a lower end thereof means for securing the tool holder to a tool string within the well bore. 
     The apparatus may further include said upper assembly and said lower assembly having means for remotely selectively connecting and disconnecting the second mechanical connector means and electrical connector means thereof. 
     The upper assembly and the lower assembly may have a sealed through passage for fluid to pass through the apparatus. 
     The means for remotely selectively connecting the second mechanical connector means of the upper assembly and the lower assembly may include a latching connector. This latching connector may include a plurality of spring-loaded latch keys located in the upper assembly for latching into a receptacle in the lower assembly. 
     The electrical connector means of the upper assembly and lower assembly may include a male-half electrical connector in the upper assembly and a mating female-half electrical connector in the lower assembly. 
     The latched keys of the upper assembly may be adapted to contact a reduced diameter portion of the tool holder resulting from movement of the tool string upwardly to compress the latch keys out of engagement with the receptacles to disconnect the upper assembly from the lower assembly. 
     The latch keys of the lower assembly may engage with a corresponding profile within the tool holder to hold the tool string in place within the tool holder. 
     The latch keys of the upper assembly may be operated to contact a reduced diameter portion of the tool holder resulting from movement of the tool string downwardly to compress the latch keys out of engagement with the receptacle to disconnect the tool string from the tool holder and into the well bore. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sectional view of one embodiment of a coil connector for use with the remote operated coil connector apparatus of the invention; 
     FIG. 2 is a sectional view of one embodiment of an upper assembly of the apparatus; 
     FIG. 3 is a sectional view of an embodiment of the lower assembly of the apparatus; and 
     FIG. 4 is a sectional view of an embodiment of a tool holder for use with the apparatus. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With respect to FIG. 1, the coiled tubing  1  is shown with a coiled tubing connector having helical serrated slips  2  that grip the coiled tubing by a wedging action. Thus, an increase in tension between the tool string (not shown) and coiled tubing  1  results in an increased grip by the helical serrated slips. The slips are designed with two opposed handed sets of helical serrations  2   a  and tangs  2   b  that key the slip to the bottom sub  3  to provide torque resistance. 
     A twin flapper check valve  5  with cable bypass  4  prevents the backflow of well fluids into the coil in the event of failure or damage of the coiled tubing string or surface equipment. A bypassing cable (not shown) is packed off with dual rubber elements  4   a  for forming a cavity  4   b  which is pumped with grease to form a liquid seal around the cable. The valve  5  provides a fluid flow path through the lower tool string sufficient to feed jetting/simulation fluids and operate tools and hydraulic manipulation tools to the well bore. 
     A cable anchor  8  is provided in fluted housing  6  to permit fluid flow below the valve  5 . It comprises a retainer  7  with an internal taper and housing  7   a  that has a matching tapered collet  8   a  with internal serrated teeth (not shown). The retainer  7  is fed over the cable followed by the housing  7   a . Thus, by screwing the retainer  7  into the housing  7   a  the serrated teeth are forced to grip the cable to provide a stable anchor point. Depending upon the type of cable used, the cable outer and inner armor may then be cut back flush to the ends of the cable anchor  8  to expose the insulated 
     The upper assembly shown in FIG. 2 comprises a series of spring-loaded latch keys  9  designed to locate and latch into a receptacle  16  in the lower assembly of FIG.  3 . The keys  9  are retained externally by retainer rings  10  attached to the body of the upper assembly. Once the keys  9  are latched into the receptacle in the lower assembly, a joint is formed which can only be released by extraneous means provided by the tool holder which will be later described. 
     Internally, the lower body  11  of the upper assembly houses a bulkhead carrier  12  for a single or multiple electrical pressure resistant connectors  13 . The coiled tubing cable-core conductors may be connected to these connectors. The bulk head carrier  12  when mated with the lower assembly provides a chamber that is pressure resistant to the well and to internal coiled tubing fluid. The bulkhead carrier  12  is oriented to the body  11  by an integral key  14 . The upper and lower assemblies are aligned by a cam profile  15 . This is shown as a multi-profile cam, but may be a single cam depending upon the application. The cam profile is self-aligning as the upper and lower assemblies are pushed together. This ensures correct alignment for the connectors  13  in order to form a sealed electrical connection. The male fluid union  29  of the upper assembly with external seals  29   a  will be engaged into the seal receptacle  30  provided in the lower assembly, as shown in FIG. 3, to provide a continuous, pressure containing through passage. 
     With reference to FIG. 3, the lower assembly comprises a latch receptacle  16  to receive the keys  9  of the upper assembly. Once the keys  9  of the upper assembly are latched into this receptacle  16 , a connection is formed which can only be released by extraneous means provided by the tool holder, which will be later described. 
     Internally, the latch receptacle  16  houses a bulkhead carrier  18 , which houses a multiple of electrical connectors  17  to match the male connectors  13  of the upper assembly. The bulk head carrier  18  is free to rotate radially. It has a single or series of cam profiles  21  designed to align with the mating profiles  15  in the upper assembly, prior to forming the electrical connection. The cam profiles  21  are therefore self-aligning as the upper and lower assemblies are pushed together. The bulkhead carrier  18 , when mated with the upper assembly, provides a chamber  17   a  that is pressure resistant to the well and to internal coiled tubing fluid. 
     Externally, a series of spring-loaded downward-facing anchor keys  20  are positioned to provide a positive, downward load-bearing seat  20   a  against a mating shoulder  25  housed within the tool holder shown in FIG.  4 . This structure is capable of holding up the hanging weight of the tool string. 
     Similarly, a set of upwardly facing anchor keys  19  are positioned to provide a positive, upward load-bearing seat ( 19 A) against a mating shoulder  24  housed within the tool holder of FIG. 4, thereby acting as a positive stop for the location of the tool string. The shoulder  24  will also enable an over-pull to be taken through the coiled tubing once the upper assembly has been connected to the lower assembly. 
     The tool holder shown in FIG. 4 is incorporated into the apparatus in accordance with the invention to provide an interface between the handling equipment and the upper and lower assemblies. Within the handling equipment, a multiple of tool strings can be housed in carousels (not shown) ready for use, and can be selected at the well head as desired to accommodate the intervention operation. The main requirement of the tool holder is to provide the tool string, within each carousel, with a holding mechanism that is compatible with the upper and lower assemblies of the remote operated coil connector apparatus. 
     As shown in FIG. 4, housed within the body  22  of the tool holder is a spring-loaded catcher sleeve  23 . Spring  28  of the catcher sleeve  23  is pre-loaded to a set force. At each end of the internal diameter of the catcher sleeve  23 , square load-bearing shoulders  24  and  25  are formed into which the anchor keys  19  and of the lower assembly will respectively locate. 
     When the upper assembly is connected to the lower assembly, an upward overpull with the coiled tubing is required to confirm that the joint is positively latched. This is achieved by picking up the tool string, through the load-bearing shoulders  24  of the catcher sleeve  23 , so that the pre-loaded spring  28  compresses. 
     If the tool string is pulled beyond a certain force limit, the latch keys of the upper assembly will contact a reduced neck  26  in the upper body of the tool holder, at which point, the latch keys will be compressed and released from the lower assembly latch receptacles. 
     Similarly, after confirming that the joint between the upper and lower assemblies is positively latched so that the tool string may be inserted into the well, the upper and lower assembly is pushed down by the coiled tubing against the lower load-bearing shoulder  25  of the catcher sleeve  23  so that the pre-loaded spring  28   
     If the tool string is pushed beyond a certain predetermined force, the anchor keys of the lower assembly will contact a reduced neck  27  in the lower body of the tool holder at which point the anchor keys will be compressed and released from the catcher sleeves. This disconnects the tool string from the tool holder and allows the coil string to be deployed into the well for the required operation. 
     When the operation is completed, the tool string is returned to the tool holder, the lower assembly will locate into the catcher sleeve  23 , whereupon and over-pull/push with the coiled tubing will confirm that the tool string is positively located. The upper assembly joint can then be released by over-pulling as previously described, leaving the lower assembly with the tool string in place in the tool holder and separated from the upper assembly.