Abstract:
An orientation joint for a subsea landing string equipped to maintain both unitary and telescoping configurations. For example, the joint may maintain a unitary configuration to provide continuous orientation definition while lowering a landing string within a blowout preventer (BOP). Additionally, the orientation joint may be configured to telescope and provide an appropriately sized uniform outer diameter surface to enable a sealing engagement with an aligned ram of the BOP.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present document is based on and claims priority to U.S. Provisional Application Ser. No. 61/333549, filed May 11, 2010. 
     
    
     FIELD 
       [0002]    Embodiments described relate to landing strings for delivering a host of interventional and/or monitoring tools to a downhole location in a well. More specifically, embodiments of subsea landing strings are detailed which are configured for uniquely interfacing with blowout preventer equipment. Thus, well integrity and access may be enhanced. 
       BACKGROUND 
       [0003]    Exploring, drilling and completing hydrocarbon and other wells are generally complicated, time consuming, and ultimately expensive endeavors. As a result, over the years, a significant amount of added emphasis has been placed on well monitoring and maintenance. 
         [0004]    In terms of interventional monitoring and maintenance in subsea hydrocarbon operations, various tools and testing devices may be provided by way of a subsea landing string system. Such a system may enable completion, flow testing, intervention, and other subsea well operations to be performed from a floating vessel. Generally, the landing string is run down through a marine riser and access to the well is achieved through a BOP (blowout preventer). The BOP contains a number of features used to ensure well integrity, including any of several shearing and sealing rams, as well as some operation-specific features, such as orientation pins used to define the orientation of the landing string. 
         [0005]    One of the more significant considerations in designing a subsea landing string is the space-out of the landing string within the BOP. The “space-out” refers to the location of various features of the landing string relative to the relevant features of the BOP, in particular shearing and sealing rams, as well as orientation pins and other features. It is important that the landing string be configured in such a way that the necessary BOP functionality (e.g., sealing) can be maintained. 
         [0006]    With such landing string challenges as noted above, one feature that may be included, particularly when running well completions, is a Tubing Hanger Orientation Joint (THOJ). This is a section of the landing string that defines the rotational orientation of the landing string relative to the BOP in order to properly install or interface with the tubing hanger for vertical production trees. In many cases the THOJ achieves this orientation through the use of an orientation helix and a slot (keyway) or the like, which interact with a pin or key projecting into the BOP interior. Typically these orientation features gradually impose the correct orientation over some distance of vertical travel as the landing string is lowered into the BOP. 
         [0007]    Unfortunately, the required distance of vertical travel to achieve proper orientation contributes to a minimum height requirement for the orientation joint. This in turn, may conflict with the desired BOP space-out for performing certain well operations. Addressing this conflict may potentially be achieved by performing the necessary operations in multiple runs, each with a different landing string configuration. However, the requirement of multiple runs and landing string change outs would be quite time-consuming, dramatically increasing the cost of operations. 
       SUMMARY 
       [0008]    Embodiments of a Tubing Hanger Orientation Joint (THOJ) are disclosed. These embodiments are directed at the potential conflict between the long distance of vertical travel needed to define the orientation of the landing string, and the requirement of placing an appropriate sealing surface at a particular location within a blowout preventer (BOP). More specifically, a sealing interface is generally sought across the BOP sealing rams, most likely upon landing out or connecting to a tubing hanger. In such a case the necessary vertical height of the orientation feature (such as a helix of the joint) might result in this feature blocking a necessary BOP ram, rendering it ineffective. Thus, in order to avoid eliminating the sealing capacity of the ram, the THOJ is configured to telescope after landing. As such, a continuous orientation feature (such as a helix) for orienting the landing string may be available until proper landing is achieved. Thereafter, the joint may be split and telescoped to provide a sealing (or shearing) surface across the desired BOP rams, as may be required for subsequent operations. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIGS. 1   a  and  1   d  is a side comparison view of an embodiment of a telescoping hanger joint in retracted and extended positions. 
           [0010]      FIGS. 1   b  and  1   c  are sectional views of a side comparison of an embodiment of a telescoping hanger joint in a retracted and extended position. 
           [0011]      FIGS. 2   a  and  2   b  are side cross-sectional comparison views of an embodiment of the hanger joint in retracted and extended positions within a space-out location of blowout preventer equipment. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Embodiments herein are described with reference to certain types of landing strings and blowout preventer equipment. For example, these embodiments focus on completion assemblies for subsea operations. However, a variety of alternative operations may take advantage of embodiments of a telescoping joint for a landing string as detailed herein. 
         [0013]    The present application design proposes a telescoping THOJ, which provides an orientation helix for orienting the landing string, but which subsequent to landing may be split and telescoped to provide a sealing (or shearing) surface across the desired BOP rams, as may be required for subsequent operations. In  FIGS. 1   a - 1   d , the THOJ  1  can be seen in its retracted and extended positions. In the retracted position, the orientation helix  4  is continuous (or substantially continuous in the sense that a pin or other protuberance will be guided along the helix without). This helix  4  engages a pin  12  protruding into the interior of the BOP  10  (pin shown in  FIGS. 2   a  and  2   b ) to rotate the landing string to the correct orientation as the landing string is lowered, until the correct orientation is reached and the BOP  10  pin  12  reaches the vertical slot  5 . The landing string is then fully landed out with the correct orientation. In the extended position, the helix  4  is split to expose a ported slick joint  8  against which the BOP pipe ram  11  can seal. The ported slick joint  8  can have a uniform outer diameter surface adapted for sealing with the BOP pipe ram  11 . The BOP  10  space-out is shown in  FIG. 2   b.    
         [0014]    Looking more specifically at  FIGS. 1   a - 1   d,  a THOJ  1  is shown having a lower THOJ  2  and an upper THOJ  3 . When in the retracted position, the helix  4  of the THOJ  1  forms a continuous helix stepped surface which leads to vertical slot  5 . In practice, when lowered into a BOP  10  a pin  12  will contact the helix  4  and be forced along the helix  4  and into the vertical slot  5 . This interaction between the helix  4 , pin  12  and vertical slot  5  orients the THOJ  1  into a proper angular position. 
         [0015]    The helix  4  can be a single stepped helix part or can be multiple helix parts. According to one embodiment, the helix  4  can be a first helix part and a second helix part where the first helix part and the second helix part converge toward one another as they are closer to the slot  5 . In another embodiment the second helix part can mirror the first helix part. The helix parts can be concave in shape and face one another in the concave direction. According to yet another embodied feature, the step of the first helix part can face the step of the second helix part, thereby defining a low region between the helix parts to guide the pin  12  into the slot  5 . The helix parts can converge and meet at an apex of the helix  4 . 
         [0016]    Once the THOJ  1  is oriented properly, the THOJ  1  is extended from the retracted position ( FIGS. 1   a  and  1   b ) to the extended position ( FIGS. 1   c  and  1   d ). When in the extended position, a ported slick joint  8  (seal surface) is exposed to the BOP pipe ram  11 . Also, the helix  4  is divided into a lower helix  6  and an upper helix  7 . The extension of the THOJ  1  can be accomplished by applying tensile force on the THOJ  1 . Also, a hydraulic force (e.g., hydraulic chambers in the THOJ) could be applied to extend the THOJ  1 . 
         [0017]      FIGS. 2   a  and  2   b  show a wellhead  13  in connection with the BOP  10 . A BOP Wellhead Connector  14  and Tubing Hanger  9  are also schematically shown. 
         [0018]    In this way, the proposed orientation joint provides both a continuous helix  4  for orienting the landing string, and a sealing surface  8  (e.g., ported slick joint) against which the BOP pipe rams  11  can close once the string is landed. 
         [0019]    The preceding description has been presented with reference to presently preferred embodiments. Persons skilled in the art and technology to which these embodiments pertain will appreciate that alterations and changes in the described structures and methods of operation may be practiced without meaningfully departing from the principle, and scope of these embodiments. Furthermore, the foregoing description should not be read as pertaining only to the precise structures described and shown in the accompanying drawings, but rather should be read as consistent with and as support for the following claims, which are to have their fullest and fairest scope.