Abstract:
A running tool for use in handling control modules on a subsea production tree. The running tool is deployable on wire line and includes a column like body and a connector adapted for connection to the production tree. The running tool also includes a hoist system that is selectively positioned by a swiveling jib crane for handling the control modules. A replacement control module can be included with the running tool when the tool is deployed from above the sea surface. After the running tool connects to the production tree, the jib crane can position the hoist for attachment to and removal of an existing control module on the production tree. The hoist can then to attach to and install the replacement control module and can be further manipulated to retrieve the existing control module and stow it onto the body.

Description:
1. FIELD OF THE INVENTION 
     This invention relates in general to production of oil and gas wells, and in particular to a device and method for delivery and/or retrieval of modules used in conjunction with subsea hydrocarbon production. 
     2. DESCRIPTION OF RELATED ART 
     Subsea wellbores are formed from the seafloor through subterranean formations lying underneath. Systems for producing oil and gas from subsea wellbores typically include a subsea wellhead assembly set over a wellbore opening. A typical subsea wellhead assembly includes a high pressure wellhead housing supported in a lower pressure wellhead housing and secured to conductor casing that extends downward past the wellbore opening. Wells are generally lined with one or more casing strings coaxially inserted through, and significantly deeper than, the conductor casing. The casing strings are suspended from casing hangers landed in the wellhead housing. One or more tubing strings are provided within the innermost casing string; that among other things are used for conveying well fluid produced from the underlying formations. A production tree mounts to the upper end of the wellhead housing for controlling the well fluid. The production tree is typically a large, heavy assembly, having a number of valves and controls mounted thereon 
     Controls mounted on a production tree may be in the form of a subsea control module. Typically, subsea control modules are modular devices that regulate a supply of hydraulic fluid to subsea actuators, where the actuators are generally used to open and/or close a valve or valves. A choke bridge module is another type of module that is sometimes found on a production tree. Choke bridge modules generally regulate production flow from a production tree with an integrated flow restriction. Subsea control modules and choke bridge modules typically require replacement, installation, or removal during the operational life of the subsea wellhead assembly. 
     SUMMARY OF THE INVENTION 
     Disclosed herein is a running tool for handling a control module attachable to a subsea production tree. In an example embodiment the running tool includes a body having a connector that attaches to a subsea wellhead assembly. Also included is a swivel on the body distal from the connector that rotates about an axis of the body. A hoist assembly is included that couples with the swivel. 
     Also disclosed is a method of handling a control module subsea. In an example embodiment the method includes providing a running tool, where the running tool includes a body having an axis and a hoist assembly. The running tool is deployed subsea on a wire line to a subsea wellhead assembly and a control module is retrieved from the wellhead assembly using the hoist assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side partial sectional view of an example embodiment of a running tool being lowered to a subsea wellhead assembly. 
         FIGS. 2-4  are side partial sectional views of the running tool of  FIG. 1  coupled to the subsea wellhead assembly and replacing a subsea module on the wellhead assembly. 
         FIG. 5  is a side partial sectional view of the running tool of  FIG. 1  removing a subsea module from the wellhead assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The apparatus and method of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. This subject of the present disclosure may, however, be embodied in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. For the convenience in referring to the accompanying figures, directional terms are used for reference and illustration only. For example, the directional terms such as “upper”, “lower”, “above”, “below”, and the like are being used to illustrate a relational location. 
     It is to be understood that the subject of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments of the subject disclosure and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. Accordingly, the subject disclosure is therefore to be limited only by the scope of the appended claims. 
     Referring now to  FIG. 1 , a side view of a running tool  10  is shown being deployed subsea on lift line  12 . In the example of  FIG. 1 , the lift line  12  is being reeled from a vessel  14  shown at the sea surface. In the example of  FIG. 1 , the vessel  14  is a workboat of the type typically used for subsea operations. Optionally, the vessel  14  can be an offshore rig, a floating production storage and offloading vessel (FPSO), or any type of vessel used for operations associated with a subsea assembly. 
     The running tool  10  is shown being lowered towards a subsea wellhead assembly  16  shown disposed at the sea floor. The running tool  10  includes a body  18 , which in an example embodiment, is an elongate substantially cylindrical member. Shown on an upper end of the body  18  is a swivel portion  20  that is substantially coaxial with the body  18  and rotatable about an axis. A portion of a hoist assembly  22  attaches to a side of the swivel portion  20  and includes a jib or boom  24  shown as an elongated member that projects radially outward from the swivel portion  20 . Supported on the jib  24  is a pulley  26  that is selectively movable along the length of the jib  24 . A line  28 , separate from the lift line  12 , extends between the pulley  26  and the body  18 . The running tool  10  attaches to the lift line  12  with a lift line attachment  29  shown coupled between the lift line  12  and swiveling portion  20 . A replacement choke bridge module  30  is shown attached on a lateral side of the body  18 . Choke bridge module  30  is releaseably parked on the body  18  and is a component to be attached to subsea equipment. In an example embodiment, the choke bridge module  30  can be deployed with the running tool  10  and used to replace an existing choke bridge module  31  shown provided with the wellhead assembly  16 . The choke bridge modules  30 ,  31  can be used for regulating and/or diverting flow produced or otherwise flowing from the subsea wellhead assembly  16 . 
     Still referring to  FIG. 1 , the wellhead assembly  16  includes a wellhead housing  32  set over a well bore  34  bored through formation beneath the sea floor. A production tree  36  attaches to an upper end of the wellhead housing  36 . A main bore  38  (shown in phantom line) extends substantially vertically through the wellhead housing  32  and production tree  36 . A swab valve in the main bore  38  controls access through the main bore  38 . An annular tree mandrel  39  is shown projecting upward from the production tree  36  from the main bore  38  and through a rectangular top plate  40 . Column struts  42  support the top plate  40  over the production tree  36 . Also included with the subsea wellhead assembly  16  are flow lines  44  coupled to lateral sides of the production tree  36 . The flow lines  44  each include a wing valve  46  therein for controlling and regulating flow through the flow lines  44 . 
     In  FIG. 2  the running tool  10  is shown landed on the wellhead assembly  16  with the body  18  substantially coaxial with the main bore  38  and tree mandrel  39 . The running tool  10  is shown having a funnel  50  on its lower most portion to facilitate landing onto the tree mandrel  39 . The funnel  50  is a conically shaped annular member with an opening on a lower end and an inner circumference that narrows with distance away from the opening. The funnel  50  can help to guide the running tool  10  to a desired orientation with the tree mandrel  39 . Shown adjacent the funnel  50  is a connector  52  that can be manipulated to grapple the outer circumference of the tree mandrel  39  to rigidly attach the running tool  10  to the wellhead assembly  16 . In an example embodiment the connector  52  is annular and includes clamps on an inner circumference that can selectively attach on the outer circumference of the tree mandrel  39 . One example embodiment the connector  52  is a Vetco MDH4 connector. 
     The example of  FIG. 2  further illustrates the line  28  having been reeled out from the running tool  10  to have an attachment end extending past the hoist assembly  22 . The attachment end of the line  28  is connected with the existing choke bridge module  31 . In an example embodiment, an actuator  54  is illustrated set within the body  18  for supplying the line  28  from the running tool  10 . In one example, the actuator  54  includes gears (not shown) connected to a spool or reel  55  within the body  18 . The line  28  can be stored on the reel  55  within the body  18  and then reeled out for connection to the choke bridge module  31 , or other object. The actuator  54  may be powered by a motor  56 , also shown within the housing  18  and connected to the actuator  54  via a shaft. Other connection means such as belts or chains may be employed as well. To effectuate connection between the line  28  and choke bridge module  31  a connector  57  is illustrated that can selectively couple to the original or existing choke bridge module  31  as well as the replacement choke bridge module  30 . 
     Referring now to  FIG. 3  the existing choke bridge module  31  has been released and lifted from its original location on the subsea wellhead assembly  16  and parked on the top table  40 . Additionally, the hoist assembly  22  is further manipulated so that the swivel  20  rotates about the axis A X  thereby aligning the line  28  with the replacement choke bridge module  30 . Also optionally, as indicated by the arrow A, the reel  26  has been moved radially inward along the boom  24  for a precise alignment with the replacement choke bridge module  30 . Additionally, the line  28  is shown connected to the replacement choke bridge module  30  via connector  57 . Arrow A R  illustrates one example direction of swiveling rotation of the swivel  20 . 
     Referring to  FIG. 4 , the hoist assembly  22  is further actuated in a position to land the replacement choke bridge module  30  in the same location where the original choke bridge module  31  was located. Rotational swiveling movement of the swivel  20  is shown by arrow A R  and lateral movement of the pulley  26  is illustrated by arrow A. A remotely operated vehicle  58  is illustrated that may be used to assist in positioning the replacement choke bridge module  30  on the production tree  36 . A control tether  60  attaches to an end of the ROV and used for powering and/or control of the ROV. In the example of  FIG. 4 , the original choke bridge module  31  and replacement control module are modules having a choke bridge for regulating flow from the production tree  36  to processing or other terminal locations. 
     Optionally, as shown in  FIG. 5 , the procedures described herein may be used to replace a subsea control module  62  shown attached to the production tree  36 . The subsea control module  62  can be used for control of actuators associated with the subsea wellhead assembly  16 , such as for opening and closing the swab valve and/or wing valves. In an example embodiment, subsea control module  62  includes hardware and software for controlling operation of systems within or associated with the subsea wellhead assembly  16 . For example, the flow of electricity or hydraulics may be regulated through the subsea control module  62  for actuating movable devices, such as valves, located on the subsea wellhead assembly  16 . 
     While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention. For example, in addition to the modules  30 ,  31 ,  62  discussed above, other wellhead components may be replaced or installed using the devices and methods provided herein. Such additional components include choke inserts, sand detectors, and flow control devices. Thus, in an example embodiment, a hoist assembly  22  could be deployed having one or more of a choke bridge module, subsea control module, a choke insert, a sand detector, flowmeter control unit, and a flow control device. Moreover, the hoist assembly  22  can also carry with it the tools for replacing any of the components, such as an interface tool. In an example embodiment, an interface tool is included with the connector  57  for interfacing with the component being replaced. One advantage of the device and method described herein is the running tool  10  can be lowered subsea at a rate of descent so it “softly” lands on the wellhead assembly  16  without imparting a damaging impulse in the running tool  10  or component being replaced.