Abstract:
A system for setting and retrieving a tool including a tubular having a first profile and a tool having a second profile, the first and second profiles complementarily formed and engagable together for enabling the tool to be located in a borehole with respect to the tubular, the first profile or the second profile at least partially formed from a degradable material, the degradable material degradable upon exposure to a downhole fluid.

Description:
BACKGROUND 
     Tools in the downhole drilling and completions industry are often located in a borehole by the use of no-go profiles (or landing nipples, radially inner restrictions, etc.). While these no-go profiles are relied upon for providing positive indication that a tool is properly set, too much load on the tool can deform or swage the tool and/or the no-go profile. If a tool becomes swaged into a no-go profile, retrieval of the tool can become difficult and the tool and profile can become damaged. As a result, advances to the setting and subsequent retrieval of tools, particularly those overcoming the above problems, are well received by the industry. 
     BRIEF DESCRIPTION 
     A system for setting and retrieving a tool including a tubular having a first profile and a tool having a second profile, the first and second profiles complementarily formed and engagable together for enabling the tool to be located in a borehole with respect to the tubular, the first profile or the second profile at least partially formed from a degradable material, the degradable material degradable upon exposure to a downhole fluid. 
     A system for setting and retrieving a tool including an engagement including a first profile of a first component and a second profile of a second component, the engagement operatively arranged for locating the first component in a borehole with respect to the second component, the first profile at least partially degradable by exposure to a downhole fluid. 
     A component of a no-go engagement including a first profile operatively arranged to engage with a second profile of the no-go engagement for locating a tool downhole, the first profile at least partially degradable upon exposure to a downhole fluid. 
     A method of setting and retrieving a tool downhole including landing a first profile of a tool at a second profile of a tubular, exposing the first profile or the second profile to a downhole fluid for degrading the first profile or the second profile at least partially. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIG. 1  is a quarter-sectional view of a system having a no-go engagement between a tubular and a tool; 
         FIG. 2  is an enlarged view of the area generally encircled in  FIG. 1 ; 
         FIG. 3  is a quarter-sectional view of the system of  FIG. 1  having dogs of the tool set into recesses of the tubular; 
         FIG. 4A  is a cross-sectional view of the system taken generally along line  4 A- 4 A in  FIG. 1 ; 
         FIG. 4B  is a cross-sectional view of the system taken generally along line  4 B- 4 B in  FIG. 1 ; 
         FIG. 5  is a quarter-sectional view of the system of  FIG. 1  after application of an additional load on the tool; 
         FIG. 6  is an enlarged view of area generally encircled in  FIG. 5 ; and 
         FIG. 7  is a quarter-sectional view of the system of  FIG. 1  after a ring of the no-go engagement has been removed by degradation. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
     Referring now to  FIG. 1 , a system  10  is shown having a tool  12  being run in a tubular  14 . As shown in more detail in  FIG. 2 , the system  10  includes a no-go engagement  16  comprising a landing profile  18  on the tubular  14  and a no-go ring  20  on the tool  12  having a corresponding profile  22 . Once received at the landing profile  18 , positive interference or radial overlap with the profile  22  of the ring  20  prevents the tool  12  from traveling further downhole. The tool  12  is illustrated throughout the Figures in the form of a lock mandrel, but it will be appreciated that other tools or downhole components (the term “tool” used collectively herein) could utilize the no-go engagement of the current invention. That is, for example, tools benefiting from the current invention include those that carry a load in excess of the setting load such as plugs, tubing hangers, check valves, etc. 
     Accordingly, after landing at the profile  18 , a setting load is applied to the tool  12 , specifically on a sub  24  for the tool  12 . The sub  24  includes a mandrel  26  for engaging with one or more dogs  28  and expanding the dogs  28  radially outwardly into complementarily formed recesses  30  in the tubular  14 , as shown in  FIG. 3 . This creates positive interference or a radial overlap between the dogs  28  and the tubular  14 , which can be appreciated by comparing  FIGS. 4A and 4B . 
     Under high pressure or an additional force or load after being set (e.g., the tool including or being formed as a plug housing, check valve retainer, tubing hanger, etc., as noted above), the tool  12  is shifted downhole such that the dogs  28  result in an engagement at a surface  32  of the recesses  30 , as shown in  FIG. 4 . Once the dogs  28  are fully engaged against the walls of the recesses  30 , the tubular  14 , via the dogs  28 , picks up the weight of the tool  12  and any components hanging therefrom or pressures applied thereto. 
     Shifting the dogs  28  downhole to engage at the surface  32 , however, causes the ring  20  of the tool  12  to also shift downhole, becoming swaged into the landing profile  18  of the tubular  14 . As shown in more detail in  FIG. 5 , the ring  20  is deformed a distance D into the landing profile  18  of the tubular  12 . This swaging makes retrieval of the tool  12  difficult as it significantly increases the force required to pull the ring  20 , and therefore the tool  12 , free of the tubular  14 . 
     In order to facilitate the retrieval of the tool  12  in the system  10 , the no-go engagement  16  is at least partially degradable. “Degradable” is intended to mean that the ring is disintegratable, dissolvable, corrodible, consumable, or otherwise removable. It is to be understood that use herein of the term “degrade”, or any of its forms, incorporates the stated meaning. The ring  20  is formed as any known degradable material, such as a metal, polymer, composite, etc. that is removed or weakened by exposure to a downhole fluid, for example, water, oil, acid, brine, etc. In  FIG. 6  the ring  20  has been removed by exposure to one of the downhole fluids, for example, by spotting acid to the ring  20 . In another example, the material of the ring  20  could be selected such that is degrades more slowly over time, and is sufficiently weakened or removed by the time any additional load is applied to the tool  12 . Once the ring  20  is removed, there is no longer a swaged engagement of the tool  12  with the tubular  14 , thereby facilitating removal of the tool  12 . It is also to be appreciated that degrading of the ring  20  could occur before application of the additional pressure or force on the tool  12 , such that swaging never occurs, in which case the dogs  28  would engage with the surface  32  before the application of any additional pressures, loads, or forces (e.g., for or with operation of a plug, check valve, tubing hanger, etc.). 
     Although the system  10  is shown with the tool  12  disposed radially inwardly of the tubular  14 , in another embodiment a tool could be located radially outwardly of a tubular, with a degradable ring disposed radially inwardly of the tool. In another embodiment, the degradable ring could be formed as part of the tubular with the tool including a non-degradable landing profile. The ring  20  could be a c-ring, a full ring held by a retainer, a full ring that is press fit onto or into the tool or tubular, etc. Furthermore, although the term “ring” is used consistently herein, it is to be appreciated that other members or portions of a non-go engagement could be used for decreasing the amount of undesirable swaging between two components in order to facilitate retrieval of one or both of the components. 
     While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.