1. Field of the Invention
This invention relates in general to drilling and production of oil and gas wells and, in particular, to a design of a slide actuating connector for tubular members.
2. Brief Description of Related Art
A riser is a large diameter pipe used in offshore drilling, production, export, import, mining, and free standing operations to guide the tubing strings, such as drill strings or production strings, from the offshore platform to and from the subsea wellhead and to provide means for circulation of fluid. The tubing string is lowered through the riser. Fluid circulates down from the platform through the tubing string, out through the drill bit, or other sub assembly, and returns to the platform in the space between the inner diameter of the riser and the outer diameter of the tubing string. Environmental forces caused by waves, currents, and the movement of the offshore platform, as well as internal forces caused by the weight of the heavy fluids, all contribute to the substantial loads applied to the riser. Additionally, high pressure risers, utilizing surface blowout preventers, may be exposed to full wellbore pressure. The connection between each successive joint of the riser must be able to withstand such loads.
The prior art makes up the riser pipe or joint connections with bolted flange type connectors or with radially oriented screws that move dogs into and out of engagement with a profile on the riser pipe. Both of these methods require manipulation with a wrench or stud tensioning device, placing personnel in close proximity to the drilling slots for prolonged periods of time, and increasing the danger level of performing the task.
In another prior art embodiment the riser box ends are formed with pockets and locking members positioned within the pockets. The locking members have a profile that mates with a profile on a pin end of the adjacent riser. This riser assembly includes a special cam ring that is actuated by specialty equipment on the platform. The specialty equipment causes the cam to move the locking members into engagement with the profile of the pin end to secure the riser tubulars. These cam assemblies may significantly increase the cost of the platform due to the increased capital costs for the special equipment and more expensive riser members. Therefore, a riser joint that allows for a strong connection that can be rapidly made-up without placing personnel in close proximity to the drilling slots for prolonged periods of time and at a lower capital cost would be desirable.
In still another prior art embodiment, the riser ends are formed with grooves. A collet, or split ring may surround the riser ends, and a sleeve may surround the collet or split ring. The sleeve will have a specially formed thread on an inner diameter that engages with a mating thread on an outer diameter of the collet or split ring. Rotation of the sleeve relative to the collet or split ring radially contracts the collet or split ring to couple the riser ends together. In embodiments utilizing a collet, the collet has inner diameter grooves that will engage the grooves formed on the riser ends. In embodiments utilizing a split ring, the radial contraction of the split ring will cause the grooves on the riser ends to engage. In these embodiments, one riser end will have grooves on an outer diameter portion, and one riser end will have grooves on an inner diameter portion. These riser assemblies require significant manufacturing time to machine complex collet or split ring engaging components. In addition, the strength of the riser may be limited by the strength of the collet member, a member typically formed with a thinner sidewall and subjected to higher rates of fatigue failure. Still further, make-up of these connectors still require worker proximity to rotating machinery. This is a significant worker injury risk. Therefore, a riser joint that allows for a strong connection not limited by an interposed component that can be rapidly made up without complex machined components is desirable.
These and other problems are generally solved or circumvented, and technical advantages are generally achieved, by preferred embodiments of the present invention that provide a cost effective rapid make-up connector for tubular members.
In accordance with an embodiment of the present invention, a tubular connector is disclosed. The tubular connector includes a first tubular member having an axis and an end portion with grooves formed on an outer diameter of the end portion. The tubular connector also includes a second tubular member having an end portion with a plurality of box end fingers separated by slots and grooves formed on an inner surface of the box end fingers, the second tubular member being coaxial with the first tubular member. The grooves of the first tubular member are proximate to the grooves of the second tubular member when the first tubular member is inserted into the end of the second tubular member in an initial position. The tubular connector further includes an outer sleeve disposed around the box end fingers. Axial movement of the outer sleeve relative to the box end fingers causes an inner surface of the outer sleeve to slide against the outer surface of the box end fingers, causing the box end fingers to contract radially into engagement with the grooves on the end portion of the second tubular member, thereby securing the first tubular member to the second tubular member in a made-up position.
In accordance with another embodiment of the present invention, a tubular connector is disclosed. The tubular connector includes a first tubular member having an axis and an end portion with grooves formed on an outer diameter of the end portion. The tubular connector also includes a second tubular member having an end portion with a plurality of outwardly biased box end fingers separated by slots, grooves formed on an inner surface of the box end fingers, and an arcuate surface on an outer surface of the box end fingers, the second tubular member being coaxial with the first tubular member. A depth of the second tubular member grooves increases as the grooves approach the second tubular member end portion, and a depth of the first tubular member grooves decreases as the grooves approach the first tubular member end portion. The grooves of the first tubular member are proximate to the grooves of the second tubular member when the first tubular member is inserted into the end of the second tubular member in an initial position. The tubular connector further includes an outer sleeve disposed around the box end fingers and having a tapered inner surface. Axial movement of the outer sleeve relative to the box end fingers causes the tapered inner surface of the outer sleeve to slide against the arcuate outer surface of the box end fingers, causing the box end fingers to contract radially into engagement with the grooves on the end portion of the second tubular member, thereby securing the first tubular member to the second tubular member in a made-up position.
In accordance with yet another embodiment of the present invention, a method for joining tubular members is disclosed. The method provides a first tubular member having a pin end, and a second tubular member having with a box end with outwardly biased fingers and an axially moveable sleeve having an inner cam surface. The method inserts the pin end of the first tubular member into the box end of the second tubular member to align oppositely facing grooves on the box end and the pin end in an initial position. The method moves the sleeve on an outer surface of the box end axially toward the first tubular member to move the box end fingers of the box end of the second tubular member inward into engagement with the pin end of the first tubular member to fully engage the opposite facing grooves and secure the first tubular member to the second tubular member.
In accordance with still another embodiment of the present invention, a tubular connector is disclosed. The tubular connector includes a first tubular member having an axis and an end portion with threads formed on an outer diameter of the end portion, and a second tubular member having an end portion with a plurality of box end fingers separated by slots and threads formed on an inner surface of the box end fingers, the second tubular member being coaxial with the first tubular member. The threads of the first tubular member are proximate to the threads of the second tubular member when the first tubular member is inserted into the end of the second tubular member in an initial position. An outer sleeve is disposed around the box end fingers and has an inner surface. Axial movement of the outer sleeve relative to the box end fingers causes the inner surface of the outer sleeve to slide against the outer surface of the box end fingers, causing the box end fingers to contract radially into engagement with the threads on the end portion of the second tubular member. In this manner the first tubular member secures to the second tubular member in a made-up position.
An advantage of a preferred embodiment is that it provides a cost effective rapid make-up connector for tubular members. The connector may be made-up without a wrench or stud tensioning device, placing personnel in close proximity to the drilling slots for shorter periods of time, and decreasing the danger level of performing the task. In addition, the connector may be made up with no turns, significantly decreasing the time required to make up the connection. Still further, the connection does not require extensive time intensive machining of multiple components to manufacture the riser joint.
So that the manner in which the features, advantages and objects of the invention, as well as others which will become apparent, are attained, and can be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof which are illustrated in the appended drawings that form a part of this specification. It is to be noted, however, that the drawings illustrate only a preferred embodiment of the invention and are therefore not to be considered limiting of its scope as the invention may admit to other equally effective embodiments.
The present invention will now be described more fully hereinafter with reference to the accompanying drawings which illustrate embodiments of the invention. This invention 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.
In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be obvious to those skilled in the art that the present invention may be practiced without such specific details. Additionally, for the most part, details concerning rig operation, subsea assembly connections, riser use, and the like have been omitted inasmuch as such details are not considered necessary to obtain a complete understanding of the present invention, and are considered to be within the skills of persons skilled in the relevant art.
Described herein are example embodiments of connecting tubulars to form a string of tubulars. Shown in a side view in
Referring to
Referring to
In an initial position, illustrated in
Continuing to refer to
A person skilled in the art will understand that outer surface portion 33 may be conical as described above. A person skilled in the art will also understand that inner diameter 36 may be conical as illustrated herein, or may have a convex curvature. Embodiments include curved outer surface portion 33 paired with conical inner diameter 36 as shown, conical outer surface portion 33 paired with curved inner diameter 36, curved outer surface portion 33 paired with curved inner diameter 36, and conical outer surface portion 33 paired with conical inner diameter 36. A person skilled in the art will understand that in each embodiment, outer surface portion 33 will interact with inner diameter 36 such that axial movement of the sleeve 35 will cause radial movement of box end fingers 23.
Sleeve 35 may move axially relative to box end 19. Sleeve 35 may be moved axially by any suitable means. In an exemplary embodiment, a hydraulic actuation tool capable of gripping sleeve 35 with sufficient force to prevent slippage of sleeve 35 relative to the hydraulic actuation tool may be used. For example, the hydraulic actuation tool may apply an axial force to sleeve 35 of approximately 500 kips. In another embodiment, sleeve 35 may have grooves, slots, channels, or the like formed in an exterior diameter of sleeve 35. The hydraulic actuation tool may couple or secure to these grooves to apply an axial force to sleeve 35 to actuate joint 18. A person skilled in the art will recognize that any suitable means to actuate joint 18 by moving sleeve 35 is contemplated and included in the disclosed embodiments.
Upper tubular member 41 has a pin end 43 that inserts into box end 19 of lower tubular member 17. In the illustrated embodiment, upper tubular member 41 and lower tubular member 17 are coaxial with axis 24. Pin end 43 has an inner diameter equivalent to the inner diameter of lower tubular member 17 and an outer diameter less than the inner diameter of box end 19. An end of pin end 43 will land on nose seal 29 or, alternatively, upward facing shoulder 27. An annular ring 45 is formed on an outer diameter of pin end 43 and defines a downward facing shoulder 46. Annular ring 45 may be spaced from the end of pin end 43 so that annular ring 45 will be axially over box end fingers 23. In the illustrated embodiment, an upper inner diameter end of sleeve 35 may seal to annular ring 45 with a seal 48. Sleeve 35 has an upper sealing portion 52 proximate to seal 48. Upper sealing portion 52 has a substantially cylindrical inner diameter and an axial length sufficient to allow for sleeve 35 to seal at seal 48 in both the initial position and the made up position. Grooves 47 are formed on an outer diameter portion of pin end 43. As shown in
An unlocking ring 49 may be interposed between pin end 43 and sleeve 35 axially over box end fingers 23. Unlocking ring 49 includes a protrusion 51 with a ramped surface 53 on an inner portion proximate to the outer diameter of pin end 43. Ramped surface 53 may face outward toward sleeve 35. An outer portion of unlocking ring 49 will reside within a groove 55 of sleeve 35. Groove 55 will be axially below upper sealing portion 52. Thus, axial movement of sleeve 35 will result in axial movement of unlocking ring 49. When in the initial position of
Referring to
When sleeve 35 moves axially upwards groove 55 may carry unlocking ring 49 axially upwards until the top of unlocking ring 49 is proximate to, but does not contact downward facing shoulder 46. Ramped surface 53 of unlocking ring 49 moves upward relative to box end fingers 23 sufficient to allow grooves 31 to mesh fully with grooves 47. Upwards axial movement of sleeve 35 is limited by interference between inner diameter portion 36 and outer surface portion 33 as inner diameter portion 36 decreases in diameter as it approaches location 39. In the exemplary embodiment, upward facing shoulder 37 will not contact downward facing shoulder 21 when in the made up position of
To unlock the tubular members 17, 41, sleeve 35 may move axially in the opposite direction. The downwards axial movement of sleeve 35 will cause protrusion 51 to insert into the mated grooves 31, 47. Continued downwards movement will force protrusion 51 further between grooves 31, 47, releasing grooves 31 of box end fingers 23 from grooves 47 of pin end 43, thereby decoupling lower tubular 17 from upper tubular 41.
As shown in
A person skilled in the art will recognize that following engagement of grooves 31 of tubular member 17 with grooves 47 of tubular member 41, frictional forces between outer surface portion 33 of box end fingers 23 and inner diameter portion 36 of sleeve 35 will maintain engagement of tubular 17 and tubular 41 until sleeve 35 is actively moved to the initial position of
A person skilled in the art will understand that while the tubular members are referred to as a lower tubular member and an upper tubular member, it is not necessary that the members be assembled or positioned relative to one another as shown. For example, a first tubular member having pin end 43 may be axially below a second tubular member having box end 19 and the components described above. Joint 18 may then operate generally as described above. A person skilled in the art will recognize that such positioning is contemplated and included in the disclosed embodiments.
Accordingly, the disclosed embodiments provide numerous advantages. For example, the disclosed embodiments provide a cost effective rapid make-up connector for tubular members. The connector may be made-up without a wrench or stud tensioning device, placing personnel in close proximity to the drilling slots for shorter periods of time, and decreasing the danger level of performing the task. Still further, the connection uses a radially collapsible member to generate a higher axial preload force than current tubular connection systems using rotation and torque to make up.
It is understood that the present invention may take many forms and embodiments. Accordingly, several variations may be made in the foregoing without departing from the spirit or scope of the invention. Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered obvious and desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.