Patent Publication Number: US-2022220823-A1

Title: Tieback assemblies with circulating subs for well intervention

Description:
BACKGROUND 
     Field 
     The present disclosure relates to assemblies and methods for insertion into a wellbore for the isolation of an annular space of the wellbore. 
     Technical Background 
     Oil and gas wells commonly require maintenance or repair during the life of the well. Well intervention generally falls into one of two categories, light or heavy. In light well interventions, tools or sensors may be lowered into a live well while pressure is contained at the surface (i.e., production is not stopped). In heavy well interventions, production of the well may be stopped prior to the necessary maintenance or repair. Heavy well interventions may require removing the wellhead and other pressure barriers from the well to allow full access to the wellbore. Accordingly, heavy well interventions may require isolating the wellbore such that the required maintenance or repair may take place. 
     SUMMARY 
     In hydrocarbon production, a wellbore may be drilled into a hydrocarbon-rich geological formation. While drilling or after the wellbore is completely drilled, a completion system may be installed to secure the wellbore in preparation for production. The completion system may include a series of casings or liners cemented in the wellbore to help control the well and maintain well integrity. 
     Throughout the life of the well, maintenance or repair may be necessary. Completion system components may wear out during the life of the well, requiring maintenance or repair. For example, casings or liners may develop leaks, such as shallow casing leaks near the surface. As another example, multiple hydrocarbon-producing regions along the wellbore may experience crossflow, where instead of hydrocarbons flowing to the surface, they flow from one hydrocarbon-producing region to a second hydrocarbon-producing region. To solve the problems associated with leaks and crossflow, well intervention may be necessary to maintain or repair equipment. Depending on the type of well intervention, it may be necessary to kill the well (i.e., stop the well from producing by preventing hydrocarbons from flowing into the wellbore) and isolate the annular space of the wellbore. Killing the well and isolating the annular space of the wellbore may be costly, as the well is not actively producing hydrocarbons. Therefore, it is important that the well be killed quickly and efficiently such that the necessary well intervention may take place. 
     Accordingly, there is an ongoing need for assemblies and methods for isolating annular spaces of wellbores to increase the efficiency of the well intervention process. The present disclosure is directed to tieback assemblies and methods for insertion of tieback assemblies into wellbores for isolating annular spaces of wellbores for well intervention. More specifically, the present disclosure may allow for the pumping of a kill fluid down boreholes and for the circulating of the kill fluid into the annular space where a shallow caking leaks or crossflow is occurring. In the present disclosure tieback assemblies including tieback stem seals, check valves, and circulating subs may be used to increase the efficiency of isolating annular spaces of wellbores for well intervention. As further described herein, well isolation may be reached efficiently due to the assemblies and methods of the present disclosure. 
     According to one or more aspects of the present disclosure, a method of isolating an annular space of a wellbore may include inserting a tieback assembly into the wellbore. The tieback assembly may include a tieback stem seal at a downhole end of the tieback assembly, a check valve disposed vertically above the tieback stem seal, and a circulating sub disposed vertically above the check valve. The method may also include engaging the tieback stem seal of the tieback assembly at a tieback receptacle of a liner in the wellbore, passing a kill fluid into the tieback assembly, through the circulating sub, and into the annular space of the wellbore, and displacing an annulus fluid in the annular space of the wellbore with the kill fluid to isolate the annular space of the wellbore. 
     According to one or more other aspects of the present disclosure, a tieback assembly for insertion into a wellbore may include a tieback stem seal, a check valve, and a circulating sub. The tieback stem seal may define a downhole end of the tieback assembly. The circulating sub may define an uphole end of the tieback assembly. The check valve may be positioned between the tieback stem seal and the circulating sub. The tieback stem seal may be operable to be engaged into a tieback receptacle of a liner in the wellbore and to isolate an annular space of the wellbore. The circulating sub may be operable to pass kill fluid from the tieback assembly, through the circulating sub, and into the annular space of the wellbore when activated. The check valve may be operable to control a flow of fluid either through the tieback assembly or out of the circulating sub. 
     Additional features and advantages of the technology described in this disclosure will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from the description or recognized by practicing the technology as described in this disclosure, including the detailed description which follows, the claims, as well as the appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which: 
         FIG. 1  schematically depicts a tieback assembly engaged at a tieback receptacle of a liner in a wellbore, according to one or more embodiments shown and described in this disclosure; and 
         FIG. 2  schematically depicts a tieback assembly, according to one or more embodiments shown and described in this disclosure. 
     
    
    
     Reference will now be made in greater detail to various embodiments of the present disclosure, some embodiments of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts. 
     DETAILED DESCRIPTION 
     The present disclosure is directed to tieback assemblies for insertion into a wellbore for isolating annular spaces of wellbores for well intervention. In particular, the tieback assemblies of the present disclosure may include a tieback stem seal, a check valve, and a circulating sub. Referring to  FIG. 1 , one embodiment of a tieback assembly is schematically depicted. The tieback assembly may include a tieback stem seal, a check valve, and a circulating sub. The tieback stem seal may define a downhole end of the tieback assembly. The circulating sub may define an uphole end of the tieback assembly. The check valve may be positioned between the tieback stem seal and the circulating sub. The tieback stem seal may be operable to be engaged into a tieback receptacle of a liner in the wellbore and to isolate an annular space of the wellbore. The circulating sub may be operable to pass kill fluid from the tieback assembly, through the circulating sub, and into the annular space of the wellbore when activated. The check valve may be operable to control a flow of fluid either through the tieback assembly or out of the circulating sub. 
     The present disclosure is also directed to methods of isolating annular spaces of wellbores. Referring to  FIG. 2 , the methods may include inserting a tieback assembly into the wellbore, engaging the tieback stem seal of the tieback assembly at a tieback receptacle of a liner in the wellbore, passing a kill fluid into the tieback assembly, through the circulating sub, and into the annular space of the wellbore, and displacing an annulus fluid in the annular space of the wellbore with the kill fluid to isolate the annular space of the wellbore. The tieback assembly may have any of the features as described in the preceding paragraph. 
     The various apparatuses and methods for isolating an annular space of a wellbore may provide increased efficiency for the isolation of the annular space of the wellbore to conventional apparatuses and processes for isolating an annular space of a wellbore. That is, the various apparatuses and methods may allow for quick and efficient isolation of the annular space such that well intervention may be performed as quickly as possible. The apparatuses and methods of the present disclosure may allow the time that the well is killed, and therefore, not producing hydrocarbons, to be minimized. 
     As used throughout the present disclosure, the term “wellbore” may refer to a drilled hole or borehole, including an openhole or uncased portion of the well. Borehole may refer to an inside diameter of the wellbore wall (i.e., the rock face that bounds the drilled hole). As used throughout the present disclosure, the term “annular space” may refer to space surrounding one cylindrical object placed inside another, such as the space surrounding a tubular object (e.g., coiled tubing) placed in a wellbore. 
     As used throughout the present disclosure, the term “tieback stem seal” may refer to a tieback assembly component having one or more seals that may be engaged into a tieback receptacle of a liner in a wellbore to isolate the liner from an annular space of the uphole casing. 
     As used throughout the present disclosure, the term “check valve” may refer to mechanical device that permits fluid to flow or pressure to act in one direction only, and/or that may selectively block flow in a direction. 
     As used throughout the present disclosure, the term “circulating sub” may refer to a downhole tool typically used with motors or assemblies that may restrict the allowable fluid-circulation rates. The circulating sub may allow a higher circulation rate to be established by opening a path to the annulus in the top section of the tool string. 
     As used throughout the present disclosure, the term “crossover” may refer to a subassembly used to enable two components (e.g., a circulating sub and a check valve or a check valve and a tieback stem seal) with different thread types, connection types, or sizes to be connected. 
     Referring to  FIGS. 1 and 2 , a tieback assembly  100  for insertion into a wellbore  200  may include a tieback stem seal  110 , a check valve  120 , and a circulating sub  130 . The tieback stem seal  110  may define a downhole end  101  of the tieback assembly  100 . The circulating sub  130  may define an uphole end  102  of the tieback assembly  100 . The check valve  120  may be positioned between the tieback stem seal  110  and the circulating sub  130 . The tieback stem seal  110  may be operable to be engaged into a tieback receptacle  210  of a liner  220  in the wellbore  200  and to isolate an annular space  202  of the wellbore  200 . The annular space  202  of the wellbore  200  may be the space between a casing  230  and any interior components, such as the tieback assembly  100 . The circulating sub  130  may be operable to pass kill fluid from the tieback assembly  100 , through the circulating sub  130 , and into the annular space  202  of the wellbore  200  when activated. The check valve  120  may be operable to control a flow of fluid either through the tieback assembly  100  or out of the circulating sub  130 . 
     The tieback stem seal  110  may include a seal  112  around the tieback stem seal  110  along the length of the tieback stem seal. The seal  112  may be operable to isolate the annular space  202  of the wellbore  200 . The seal  112  may include a metal-to-metal seal or an elastomeric seal. The tieback stem seal  110  may be any conventional or yet to be developed tieback stem seal  110 . For an example of a tieback stem seal  110  and for further description of how a tieback stem seal  110  may operate, reference is made to U.S. Pat. No. 10,358,888 B2. 
     An uphole end  112  of the tieback stem seal  110  may include an outer diameter  114  larger than an inner diameter of the tieback receptacle  210  of the liner  220 . Those skilled in the art may refer to the outer diameter of the tieback stem seal  110  that is larger than the inner diameter of the tieback receptacle  210  of the liner  220  as a “no-go profile.” Engaging the tieback assembly  100  at the tieback receptacle  210  of the liner  220  in the wellbore  200  may include inserting a length of the tieback stem seal  110  until the no-go profile engages the tieback receptacle  210  of the liner  220 . This interaction between the outer diameter  114  of the uphole end  112  of the tieback stem seal  110  and the inner diameter of the tieback receptacle  210  of the liner  220  may form a metal-to-metal seal. 
     The check valve  120  may be positioned directly above the tieback stem seal  110  and directly below the circulating sub  130 . The check valve  120  may be operable to close and prevent upward fluid flow when the tieback stem seal  110  engaged into the tieback receptacle  210  of the liner  220  in the wellbore  200 . According to one or more embodiments, the check valve  120  may be a flapper valve. As used in the present disclosure, a “flapper valve” may refer to a type of check valve  120  having a spring-loaded plate (i.e., flapper) that may be pumped through, generally in the downhole direction, but may close if fluid attempts to flow back through the plate, generally in the uphole direction, along a drillstring or coiled tubing to the surface. 
     The check valve  120  may further include a ball seat  122 . The ball seat  122  may be operable to catch a ball  124  and direct the flow of fluid out of the circulating sub  130  and into the annular space  202  of the wellbore  200 . For an example of a ball seat  122  and for further description of how a ball seat  122  may operate, reference is made to U.S. Pat. No. 6,155,350 A. 
     As previously discussed, the circulating sub  130  may define an uphole end  102  of the tieback assembly  100 . The circulating sub  130  may be operable to pass kill fluid from the tieback assembly  100 , through the circulating sub  130 , and into the annular space  202  of the wellbore  200  when activated. The circulating sub  130  may be activated by inserting or dropping a ball  124  from the surface and pumping the ball  124  down to the ball seat  122 . Once the ball  124  is set in the ball seat  122 , pressure may be applied to force the ball  124  into the ball seat  122 , which may activate the circulating sub  130 . When the circulating sub  130  is activated, a portion of kill fluid may continue to pass through the tieback assembly  100  and into the liner. The circulating sub  130  may allow a higher circulation rate to be established by opening a path to the annular space  202  above the liner. 
     The tieback assembly  100  may further include coiled tubing  150 . The coiled tubing  150  may be in fluid communication with the surface and the tieback assembly  100 . As one skilled in the art will appreciate, coiled tubing  150  may be a continuous length of pipe wound on a spool. The coiled tubing  150  may be attached or coupled to the tieback assembly  100  such that the tieback assembly  100  may be lowered into the wellbore  200 . The coiled tubing  150  may be operable to pass kill fluid from the surface, into the tieback assembly  100 , through the circulating sub  130 , and into the annular space  202  of the wellbore  200 . 
     The tieback assembly  100  may further include one or more crossovers  140  to connect tieback assembly  100  components having different thread or connection types. The one or more crossovers  140  may be positioned between the tieback stem seal  110  and the check valve  120 , the check valve  120  and the circulating sub  130 , or both. The one or more crossovers  140  may have an internal void such that fluid (e.g., kill fluid) may be pumped from the coiled tubing  150  and along the internal bore of the tieback assembly  100 . 
     It is contemplated that other components or tools may be added to the tieback assembly  100  as necessary. Depending on the wellbore  200 , liner, type of well intervention, etc. one skilled in the art would recognize that additional components or tools may be beneficial to add to the tieback assembly  100  of the present disclosure. 
     Referring again to  FIG. 2 , a method of isolating the annular space  202  of the wellbore  200  may include inserting the tieback assembly  100  into the wellbore  200 , engaging the tieback stem seal  110  of the tieback assembly  100  at the tieback receptacle  210  of the liner  220  in the wellbore  200 , passing a kill fluid into the tieback assembly  100 , through the circulating sub  130 , and into the annular space  202  of the wellbore  200 , and displacing an annulus fluid in the annular space  202  of the wellbore  200  with the kill fluid to isolate the annular space  202  of the wellbore  200 . 
     The method of isolating the annular space  202  of the wellbore  200  may further include attaching coiled tubing  150  to the tieback assembly  100  and running the tieback assembly  100  using coiled tubing  150 . As one skilled in the art will appreciate, “running” may refer to the process of lowering a component down the wellbore to a certain location. The coiled tubing  150  may be attached to the tieback assembly  100  prior to inserting the tieback assembly  100  into the wellbore  200 . The coiled tubing  150  may fluidly couple the tieback assembly  100  to the surface, such that the kill fluid may be passed from the surface to the annular space  202  of the wellbore  200 . 
     As previously discussed in the present disclosure, the uphole end  112  of the tieback stem seal  110  may include an outer diameter  114  larger than an inner diameter  212  of the tieback receptacle  210  of the liner  220  (i.e., a no-go profile). Engaging the tieback assembly  100  at the tieback receptacle  210  of the liner  220  in the wellbore  200  may include inserting a length of the tieback stem seal  110  until the no-go profile engages the tieback receptacle  210  of the liner  220 . This coupling between the uphole end  112  of the tieback stem seal  110  and the tieback receptacle  210  of the liner  220  may create a metal-to-metal seal isolating the annular space  202  of the wellbore  200 . 
     In one or more embodiments, the tieback stem seal  110  may include a seal  110  around the tieback stem seal  110  along the length of the tieback stem seal  110 . The method of isolating the annular space  202  of the wellbore  200  may further include engaging the seal  110  with an interior surface  214  of the tieback receptacle  210  of the liner  220 . The seal  110  may include a metal-to-metal seal or an elastomeric seal. 
     The method of isolating the annular space  202  of the wellbore  200  may further include closing the check valve  120  after engaging the tieback stem seal  110  of the tieback assembly  100  at the tieback receptacle  210  of the liner  220  in the wellbore  200 . The check valve  120  may be opened while engaging the tieback stem seal  110  of the tieback assembly  100  at the tieback receptacle  210  such that kill fluid may be pumped below the tieback stem seal  110  until a borehole  204  below the tieback stem seal  110  is killed (i.e., isolated) and production has stopped. The ball  124  may then be dropped down the wellbore  200  and into the ball seat  122 , which may close the check valve  120 . After closing the check valve  120 , kill fluid may be bullheaded into the annular space  202  of the wellbore  200 . The circulating sub  130  may be operable to passing a kill fluid into the tieback assembly  100 , through the circulating sub  130 , and into the annular space  202  of the wellbore  200 . As the kill fluid is passed into the annular space  202 , any annular fluid, such as hydrocarbons or air, may be displaced back into the formation. The kill fluid may be any fluid having a density high enough to produce a hydrostatic pressure at the point of influx in a wellbore  200  that is sufficient to shut off flow from a hydrocarbon-producing region into the wellbore  200 . 
     In well interventions to fix a leak, it may be important to identify a leak depth prior to deploying and installing the tieback assembly  100 . Similarly, in well interventions to reduce or eliminate crossflow, it may be important to identify the depth of the multiple hydrocarbon-producing regions prior to deploying and installing the tieback assembly  100 . The method of isolating the annular space  202  of the wellbore  200  may further include identifying the leak depth or depth of the multiple hydrocarbon-producing regions in the wellbore  200 . Identifying the leak depth or depth of the multiple hydrocarbon-producing regions in the wellbore  200  may be accomplished by running a multi-finger caliper log, a noise log, a temperature survey, or any other known or yet to be developed method. If the leak depth or depth of the multiple hydrocarbon-producing regions is identified to be above the existing liner depth, the tieback assembly  100  may be used to isolate the annular space  202  of the wellbore  200  to kill the well while isolating the leak or stopping any crossflow between the multiple hydrocarbon-producing regions. 
     After the annular space  202  of the wellbore  200  is isolated, the method may further include installing downhole plugs to isolate a reservoir section of the wellbore  200  from a shallow leak once the annular space  202  of the wellbore  200  is isolated. Alternatively or additionally, the method may further include installing other equipment to isolate multiple hydrocarbon-producing regions such that any crossflow may be reduced or eliminated. 
     One or more aspects of the present disclosure are described herein. A first aspect of the present disclosure may include a method of isolating an annular space of a wellbore, the method comprising inserting a tieback assembly into the wellbore. The tieback assembly may comprise a tieback stem seal at a downhole end of the tieback assembly, a check valve disposed vertically above the tieback stem seal, and a circulating sub disposed vertically above the check valve. The method may further comprise engaging the tieback stem seal of the tieback assembly at a tieback receptacle of a liner in the wellbore, passing a kill fluid into the tieback assembly, through the circulating sub, and into the annular space of the wellbore, and displacing an annulus fluid in the annular space of the wellbore with the kill fluid to isolate the annular space of the wellbore. 
     A second aspect of the present disclosure may include the first aspect, further comprising attaching coiled tubing to the tieback assembly prior to inserting the tieback assembly into the wellbore and running the tieback assembly using coiled tubing. 
     A third aspect of the present disclosure may include the second aspect, where the coiled tubing fluidly couples the tieback assembly to the surface, such that the kill fluid may be passed from the surface to the annular space of the wellbore. 
     A fourth aspect of the present disclosure may include any one of the first through third aspects, where an uphole end of the tieback stem seal may comprise a no-go profile having an outer diameter larger than an inner diameter of the tieback receptacle of the liner. The method may further comprise engaging the tieback assembly at the tieback receptacle of the liner in the wellbore, which may comprise inserting a length of the tieback stem seal until the no-go profile engages the tieback receptacle of the liner. 
     A fifth aspect of the present disclosure may include the fourth aspect, where the uphole end of the tieback stem seal and the tieback receptacle of the liner may form a metal-to-metal seal isolating the annular space of the wellbore. 
     A sixth aspect of the present disclosure may include any one of the first through fifth aspects, where the tieback stem seal may comprise a seal around the tieback stem seal along the length of the tieback stem seal, and where the method may further comprise engaging the seal with an interior surface of the tieback receptacle of the liner. 
     A seventh aspect of the present disclosure may include the sixth aspect, where the seal may comprise a metal-to-metal seal or an elastomeric seal. 
     An eighth aspect of the present disclosure may include any one of the first through seventh aspects, further comprising closing the check valve after engaging the tieback stem seal of the tieback assembly at the tieback receptacle of the liner in the wellbore. 
     A ninth aspect of the present disclosure may include any one of the first through eighth aspects, further comprising identifying a leak depth in the wellbore prior to inserting the tieback assembly into the wellbore and isolating the annular space of the wellbore. 
     A tenth aspect of the present disclosure may include any one of the first through ninth aspects, further comprising installing downhole plugs to isolate a reservoir section of the wellbore from a shallow leak once the annular space of the wellbore is isolated. 
     An eleventh aspect of the present disclosure may include a tieback assembly for insertion into a wellbore, the tieback assembly comprising a tieback stem seal, a check valve, and a circulating sub. The tieback stem seal may define a downhole end of the tieback assembly. The circulating sub may define an uphole end of the tieback assembly. The check valve may be positioned between the tieback stem seal and the circulating sub. The tieback stem seal may be operable to be engaged into a tieback receptacle of a liner in the wellbore and to isolate an annular space of the wellbore. The circulating sub may be operable to pass kill fluid from the tieback assembly, through the circulating sub, and into the annular space of the wellbore when activated. The check valve may be operable to control a flow of fluid either through the tieback assembly or out of the circulating sub. 
     A twelfth aspect of the present disclosure may include the eleventh aspect, where the tieback stem seal may comprise a seal around the tieback stem seal along a length of the tieback stem seal, and the seal may be operable to isolate the annular space of the wellbore. 
     A thirteenth aspect of the present disclosure may include the twelfth aspect, where the seal may comprise a metal-to-metal seal or an elastomeric seal. 
     A fourteenth aspect of the present disclosure may include any one of the eleventh through thirteenth aspects, where the check valve may be operable to close and prevent upward fluid flow when the tieback stem seal is engaged into the tieback receptacle of the liner in the wellbore. 
     A fifteenth aspect of the present disclosure may include any one of the eleventh through fourteenth aspects, where the check valve may be a flapper valve. 
     A sixteenth aspect of the present disclosure may include any one of the eleventh through fifteenth aspects, where the check valve may further comprise a ball seat operable to catch a ball and direct the flow of fluid out of the circulating sub and into the annular space of the wellbore. 
     A seventeenth aspect of the present disclosure may include any one of the eleventh through sixteenth aspects, where the check valve may be positioned directly above the tieback stem seal and directly below the circulating sub. 
     An eighteenth aspect of the present disclosure may include any one of the eleventh through seventeenth aspects, further comprising coiled tubing in fluid communication with the surface and the tieback assembly. 
     A nineteenth aspect of the present disclosure may include the eighteenth aspect, where the coiled tubing may be operable to pass kill fluid from the surface, into the tieback assembly, through the circulating sub, and into the annular space of the wellbore. 
     A twentieth aspect of the present disclosure may include any one of the eleventh through nineteenth aspects, further comprising one or more crossovers positioned between the tieback stem seal and the check valve, the check valve and the circulating sub, or both to connect tieback assembly components having different thread or connection types. 
     It is noted that one or more of the following claims utilize the term “where” as a transitional phrase. For the purposes of defining the present technology, it is noted that this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term “comprising.” 
     Having described the subject matter of the present disclosure in detail and by reference to specific embodiments, it is noted that the various details described in this disclosure should not be taken to imply that these details relate to elements that are essential components of the various embodiments described in this disclosure, even in cases where a particular element is illustrated in each of the drawings that accompany the present description. Rather, the claims appended hereto should be taken as the sole representation of the breadth of the present disclosure and the corresponding scope of the various embodiments described in this disclosure. Further, it will be apparent that modifications and variations are possible without departing from the scope of the appended claims.