Abstract:
A slip joint assembly that is usable with a well includes first, second and third tubular housing sections; and first and second mandrels. The first tubular housing section is adapted to connect to a first tubing string segment; the second tubular housing section is adapted to connect to a second tubing string segment; the third tubular housing section disposed between the first and second tubular housing sections; the first mandrel forms a slidable connection with the first tubular housing section; and the second mandrel forms a slidable connection with the second tubular housing section.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 62/053,307 entitled, “TELESCOPING SLIP JOINT,” which was filed on Sep. 22, 2014, and is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore is drilled, various forms of well completion components may be installed in order to control and enhance the efficiency of producing the various fluids from the reservoir. 
       SUMMARY 
       [0003]    In an example embodiment, a slip joint assembly that is usable with a well includes first, second and third tubular housing sections; and first and second mandrels. The first tubular housing section is adapted to connect to a first tubing string segment; the second tubular housing section is adapted to connect to a second tubing string segment; the third tubular housing section disposed between the first and second tubular housing sections; the first mandrel forms a slidable connection with the first tubular housing section; and the second mandrel forms a slidable connection with the second tubular housing section. 
         [0004]    In another example embodiment, a system that is usable with a well, includes a tubing string and a slip joint assembly, which is disposed in the tubing string to allow longitudinal expansion and contraction of the tubing string along a longitudinal axis of the assembly so that the string may change in length by up to a stroke of the assembly. The slip joint assembly includes a housing, a central portion, a first mandrel and a second mandrel. The first mandrel extends from the central portion into the housing in a first direction along the longitudinal axis to provide part of the stroke; and the second mandrel extends from the central portion into the housing in a second direction along the longitudinal axis to provide the remaining part of the stroke. The second direction is opposed to the first direction. 
         [0005]    In yet another example embodiment, a technique that is usable with a well includes running a tubing string in the well and using a telescoping symmetrical slip joint in the tubing string to accommodate thermal expansion or contraction of tubing string material. 
         [0006]    Other advantages and features will become apparent from the following drawings, description, and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a schematic of a well-based system according an example implementation. 
           [0008]      FIG. 2  is a cross-sectional view of a symmetric telescoping slip joint assembly of the tubing string of  FIG. 1  illustrating the assembly in a fully refracted state according to an example implantation. 
           [0009]      FIG. 3  is a cross-sectional view of the symmetric telescoping slip joint assembly in a fully extended state according an example implementation. 
           [0010]      FIG. 4  is a cross-sectional view of the telescoping slip joint assembly taken along line  4 - 4  of  FIG. 2  according to an example implementation. 
           [0011]      FIG. 5  is a flow diagram depicting a technique to accommodate thermal expansion and contraction in a tubing string according to an example implementation. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    In the following description, numerous details are set forth to provide an understanding of the present disclosure. However, it will be understood by those skilled in the art that the embodiments of the present disclosure may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible. 
         [0013]    In the specification and appended claims: the terms “connect”, “connection”, “connected”, “in connection with”, and “connecting” are used to mean “in direct connection with” or “in connection with via one or more elements”; and the term “set” is used to mean “one element” or “more than one element”. Further, the terms “couple”, “coupling”, “coupled”, “coupled together”, and “coupled with” are used to mean “directly coupled together” or “coupled together via one or more elements”. As used herein, the terms “up” and “down”, “upper” and “lower”, “upwardly” and downwardly”, “upstream” and “downstream”; “above” and “below”; and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly describe some embodiments of the disclosure. 
         [0014]      FIG. 1  generally depicts a well-based system  100 , in accordance with example implementations. Referring to  FIG. 1 , a tubing string  140  may be run downhole in a wellbore  120  for purposes for performing various downhole functions. For example, the tubing string  140  may be a test string, which is run downhole inside a wellbore  120  for purposes of performing formation tests, pressure tests, and so forth, downhole inside the well. In accordance with further implementations, the tubing string  140  may be run downhole for purposes other than testing. 
         [0015]    For the example implementation that is depicted in  FIG. 1 , the wellbore  120  is lined, or supported by, a casing string  130 . However, in accordance with further example implementations, the wellbore  120  may not be cased. Moreover, although  FIG. 1  depicts a vertical wellbore  120 , the tubing string  140  may be deployed in a deviated or lateral wellbore. 
         [0016]    Due to the well environment (downhole temperatures, downhole well fluids, fluids pumped downhole from the Earth surface, and so forth), the tubing string  140  may be subject to various temperature changes, which may, in turn, result in corresponding contraction and/or thermal expansion of the string  140 . The tubing string  140  may be secured in position at one or more locations along its length. In this manner, as depicted in  FIG. 1 , the tubing string  140  may be secured in place at such locations as a downhole packer  144 , at a well head and/or blowout preventer (BOP)  150 , and so forth. Due the tubing string  140  being secured at such points, thermal expansion/contraction of the string  140  may result in tubing/equipment failure downhole. 
         [0017]    For purposes of accommodating its expansion/contraction, the tubing string  140  may contain one or multiple slip joint assemblies, such as a symmetrical telescoping slip joint assembly  142  that is depicted in  FIG. 1 . For the example implementation depicted in  FIG. 1 , the slip joint assembly  142  connects an upper segment  140 - 1  of the tubing string  140  to a lower segment  140 - 2  of the string  142 . 
         [0018]    In general, a slip joint assembly, or slip joint, is used in a downhole string for purposes of allowing the string to extend and retract to compensate for thermal expansion and contraction of the string. In this manner, the slip joint has a stroke, which is the difference in length of the slip joint between its fully extended and fully contracted positions. As an example, a given slip joint may have a stroke of five to ten feet. The slip joint may also one or multiple sealing elements, which are constructed to isolate the interior of the slip joint (i.e., the interior passageway of the string) from the annulus outside of the slip joint (and string). 
         [0019]    The slip joint may be pressure balanced, which means that the slip joint is constructed to be independent of a pressure differential between the inside and outside (or annulus) of the string. In other words, for a pressure balanced slip joint, the pressure differential between the outer and inner pressures of the string does not cause the slip joint to longitudinally contract or expand during normal operations. To achieve the pressure balance, a conventional slip joint may have a relatively intricate arrangement of parts, with several components of the slip joint serving the purposes of maintaining the pressure balance (or pressure independence) of the slip joint. 
         [0020]    In accordance with example implementations that are disclosed herein, the symmetric telescoping slip joint assembly  142  has a construction that reduces its overall length (as compared to conventional slip joints), for a given stroke. In accordance with example implementations, the slip joint assembly  142  may provide the same stroke as a conventional slip joint but have an overall length that is one half of the length of a conventional slip joint. More specifically, as described herein, the slip joint assembly  142  takes advantage of its symmetric design: an upper portion of the assembly  142  provides one half of the stroke; and a lower portion of the assembly  142  provides the other half of the stroke. Moreover, due to the symmetric geometry of the slip joint assembly  142 , the assembly  142  maintains a pressure balance between the interior of the assembly  142  and an annulus  143  of the assembly  142  by maintaining the same effective area (upon which the tubing and annulus pressures act) in opposing directions. Therefore, in accordance with example implementations, a change in the tubing-to-annulus pressure does not cause a change in the length of the slip joint assembly  142 . 
         [0021]      FIG. 2  depicts the symmetrical telescoping slip joint assembly  142 , in accordance with example implementations. In particular,  FIG. 2  depicts the slip joint assembly  142  in its fully refracted state. In general, the slip joint assembly  142  is symmetric about a plane  212  that longitudinally divides the assembly  142  into two telescoping portions: an upper telescoping portion  200 - 1  (called the “upper portion  200 - 1 ” herein); and a lower telescoping portion  200 - 2  (called the “lower portion  200 - 2 ” herein). In accordance with example implementations, the upper portion  200 - 1  is formed from components that are replicas of the components of the lower portion  200 - 2 . As such, the same reference numeral is used to refer to replica components in both portions  200 - 1  and  200 - 2 , with the suffix “1” being used to denote an actual component in the upper portion  200 - 1  and the suffix “2” being used to denote an actual component in the lower portion  200 - 2 . For example, example, the slip joint assembly  142  contains a tubular housing section  210 - 1  that is part of the upper portion  200 - 1  and a housing section  210 - 2  that is a replica of the housing section  210 - 1  and is part of the lower portion  200 - 2 . As depicted in  FIG. 2 , the plane  212  bisects a tubular, central housing section  211  of the slip joint assembly  142 . Thus, the upper half of the housing section  211  is part of the upper portion  200 - 1 , and the lower half of the housing section  211  is part of the lower portion  200 - 2 . 
         [0022]    The upper housing section  210 - 1  is concentric about a longitudinal axis  201  of the assembly  142 . The upper housing section  210 - 1  is disposed above the central housing section  211  and moves with respect to the central housing section  211  along the longitudinal axis  201  to provide a stroke (called “S 1 ” in  FIG. 2 ) that is one half of the overall stroke for the assembly  142 . The upper housing section  210 - 1  is connected at its upper end to the upper segment  140 - 1  (see  FIG. 1 ) of the tubing string  140 . In this manner, in accordance with example implementations, the upper end of the upper housing section  210 - 1  is connected to (as shown at reference numeral  240 - 1 ) to a tubular connector  204  (a female connector, for example), which, in turn couples the slip joint assembly  142  to the upper  140 - 1  segment of the tubing string  140  (see  FIG. 1 ). 
         [0023]    In a similar manner, a lower housing section  210 - 2  of the lower portion  200 - 2  of the slip joint assembly  142  is concentric about the longitudinal axis  201  of the assembly  142 ; is disposed below the central housing section  211  and moves with respect to the central housing section  211  to provide a stroke (called “S 2 ” in  FIG. 2 ), which is the other half of the overall stroke for the assembly  142 . The lower housing section  210 - 2  is is connected to (as shown at reference numeral  240 - 2 ) to a tubular connector  208  (a male connector, for example), which, in turn couples the slip joint assembly  142  to the lower  140 - 2  segment of the tubing string  140  (see  FIG. 1 ). 
         [0024]    The central housing section  211  is a tubular body, which is concentric about the longitudinal axis  201  and is secured to both an upper mandrel  250 - 1  (part of the upper portion  200 - 1 ) and a lower mandrel  250 - 2  (part of the lower portion  200 - 2 ). The upper mandrel  250 - 1  is concentric about the longitudinal axis  201  and extends upwardly from the central housing section  211  into the upper housing section  210 - 1 , which circumscribes at least part of the mandrel  220 - 1 . Likewise, the lower mandrel  220 - 2  is concentric about the longitudinal axis  201  and extends downwardly from the central housing section  211  into the lower housing section  210 - 2 , which circumscribes the mandrel  250 - 2 . 
         [0025]    The mandrel  250 - 1  and the upper housing section  210 - 1  form a telescoping slip connection for the upper portion  200 - 1 ; and likewise, the mandrel  250 - 2  and the lower housing section  210 - 2  form a telescoping slip connection for the lower portion  200 - 2 . In this manner, the slip connection that is formed between the mandrel  250 - 1  and the upper housing section  210 - 1  provides the S 1  stroke for the slip joint assembly  142 ; and the slip connection that is formed between the mandrel  250 - 2  and the lower housing section  210 - 2  provides the S 2  stroke for the slip joint assembly  142 . Due to the symmetry of the slip joint assembly  142 , the overall stroke of the slip joint assembly  142  is the sum of the strokes S 1  and S 2 . 
         [0026]    The slip joint assembly  142  further contains sealing elements for purposes of forming fluid seals between the mandrels  250  and the corresponding housing sections  210 . In accordance with example implementations, the interior of the upper housing section  210 - 1  contains a channel, or groove, that holds a sealing element  230 - 1  to form a pressure/fluid seal between the upper housing section  210 - 1  and the inner mandrel  250 - 1 ; and correspondingly, an interior channel of the lower housing section  210 - 2  contains a groove that holds a sealing element  230 - 2  to form a pressure/fluid seal between the lower housing section  210 - 2  and the inner mandrel  250 - 2 . The seal  230  may be a chevron seal stack, in accordance with example implementations. 
         [0027]      FIG. 2  depicts the slip joint assembly  142  in its fully retracted state, and  FIG. 3  depicts the slip joint assembly  142  in its fully extended position. Although  FIG. 3  depicts the extension of the slip joint assembly  142  as being divided equally between the upper  200 - 1  and lower  200 - 1  portions, in operation, the upper portion  200 - 1  of the slip joint assembly  142  extends and retracts along the longitudinal axis  201  independently from the lower portion  200 - 2 . Therefore, in operation, the distance between the upper housing  210 - 1  and the central housing  211  may be different than the distance between the lower housing  210 - 2  and the central housing  211 . 
         [0028]    As depicted by the cross section of  FIG. 4 , in accordance with some implementations, the inner mandrel  250  and outer housing  210  may be connected in a manner that allows a torque force to be transferred between these components. Such a torque force transfer allows a rotational force to be applied through the slip joint assembly  142  for purposes of rotating the tubing string  141  (see  FIG. 1 ). In this manner, tubing string  141  may be rotated for purposes of setting the packer  144 , releasing the packer  144 , opening a downhole valve or performing other downhole operation. 
         [0029]    In accordance with some implementations, the lower mandrel  250 - 2  (as an example) may have channels  251 - 2  that receive associated splines  400  of the housing section  210 - 2 . For the example implementation of  FIG. 4 , four splines  400  and four associated channels  251 - 2  are shown. However, in accordance with further example implementations, the slip joint assembly  142  may contain more than four or fewer than four splines (and corresponding channels). 
         [0030]    The engagement of the splines  400  with the channels  251 - 2  allow the transfer f a torque force between the inner mandrel  250 - 2  and the outer housing  210 - 2 , while permitting longitudinal translation of the housing section  210 - 2  with respect to the mandrel  250 - 2 . The upper mandrel  250 - 1  and upper housing section  210 - 1  may have a similar spline-based connection, in accordance with example implementations. 
         [0031]    The mandrel  250  and the housing section  210  may be connected to allow a torque force connection using a connection other than a spline-based connection, in accordance with further example implementations. 
         [0032]    Referring to  FIG. 5 , thus, in accordance with example implementations, a technique  500  includes running (block  504 ) a tubing string in a well and using (block  508 ) a symmetric telescoping slip joint assembly in the tubing string to accommodate thermal expansion or contraction of tubing string material. 
         [0033]    In accordance with example implementations, the telescoping symmetric slip joint assembly may have one or more of the following advantages. The reduction of length of the telescoping symmetric slip joint assembly, as compared to conventional slip joints, enhances handling of the slip joint assembly and reduces its overall manufacturing cost. The telescoping symmetric slip joint assembly may have fewer components than the conventional slip joint, thereby translating into lower manufacturing costs. Moreover, due to a lower number of components, the number of potential leak paths (sources of potential tool failure) may be reduced. Other and different advantages are contemplated, which are within the scope of the appended claims. 
         [0034]    Other implementations are contemplated, which are within the scope of the appended claims. For example, in accordance with further implementations, a slip joint assembly may have a similar design to the slip joint assembly  142 , except that the slip joint assembly is not symmetric about the plane  212 . In this manner, the upper mandrel  220 - 1  and the upper housing section  210  may be longer than the lower mandrel  220 - 2  and lower housing section  210 - 1 , or vice versa, to impart differences between the S 1  and S 2  strokes. As another variation, in accordance with further implementations, slip joint assembly may have a similar design to the slip joint assembly  142 , except that the housing section sections  210 - 1  and  210 - 2  may be connected to the central housing section  211  (instead of being connected to the tubular connectors  204  and  208 ); and the mandrels  220 - 1  and  220 - 2  may be connected to the tubular connectors  204  and  208 , respectively (instead of being connected to the central housing section  211 ). 
         [0035]    While the present techniques have been described with respect to a number of embodiments, it will be appreciated that numerous modifications and variations may be applicable therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the scope of the present techniques.