Patent Application
20110062670
Flow control seals are well known in downhole industries such as drilling and completion industries and especially so in the hydrocarbon recovery industry. Those of skill in the art will readily recognize that all manner of seals are used including compression seals, inflatable seals, etc. for different applications in the downhole environment.
Compression set seals are traditionally fabricated from flexible rubber material. The seals are set by an axial force that may be applied mechanically by, for example, decreasing the weight of a tubing string supported by equipment uphole such as a derrick. Applying an axial force to the seal expands the seal such that the seal contacts the walls of a borehole. And while compression set seals are some of the oldest seals, and indeed some of the most reliable seals, the art is always receptive to improvements in performance.
A seal assembly including, a deformable force transmission portion having an inner surface and an outer surface, the force transmission portion operative to transmit an applied force to a component linked to the seal assembly, and deformable in a direction transverse to a main axis of the seal assembly in response to a increased applied force greater than a threshold setting force, and a flexible outer seal portion attached to the outer surface.
A method for sealing a borehole includes applying a first axial force to a seal system operative to actuate a first seal assembly, applying a second axial force greater than the first axial force operative to actuate a second seal assembly.
A seal assembly system includes a first seal assembly and a second seal assembly each having a deformable force transmission portion having an inner surface and an outer surface, the force transmission portion operative to transmit an applied force to a component linked to the seal assembly, and deformable in a direction transverse to a main axis of the seal assembly in response to a increased applied force greater than a threshold setting force, and a flexible outer seal portion attached to the outer surface.
Referring now to the drawings wherein like elements are numbered alike in the several figures:
The seal assembly 10 is capable of transmitting a compressive axial force through the force transmission portion 12, and due thereto, to components downhole of seal assembly 10. This occurs while a threshold compressive force is not achieved whereat the seal 10 will itself set. Therefore depending upon the selected threshold force dictated by the ability of the force transmission portion to hold a load without itself deforming, other tools including seals, slips, or any other mechanically activated device downhole may be set (at lower threshold loads than the seal 10) prior to seal 10 setting and effectively preventing the application of compressive force downhole thereof thereafter. It is to be understood that multiple seals 10 may be used in a single system with increasing threshold compression set levels toward a surface location and setting of all of these is effectible through the compression set concept noted herein.
After more downhole components are set, the seal assembly 10 may be set by applying a compressive axial force of greater than the threshold force to the seal assembly 10 that is sufficient to deform the force transmission portion 12. At this point the seal 10 will set substantially normally. It is noted that a byproduct of the teaching hereof may be that the seal 10 is energized to a greater degree than traditional compression set seals because of the embedded force transmission portion that will tend to want to stay deformed once deformation thereof is effected. This is because it is contemplated that the deformation of the portion 12 is plastic deformation somewhere beyond the yield point of the material employed.
While it is to be appreciated that a number of different shaped of force transmission portions 12 could be used, as illustrated, the profile of the force transmission portion 12 has a greater outer diameter in the center of the force transmission portion 12 relative to the ends. This encourages a more uniform deformation of the portion 12 thereby avoiding seal contact pressure irregularities. Other embodiments may include a force transmission portion 12 having a greater outer diameter that is offset from the center resulting in an asymmetrical profile.
Referring to
While one or more embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.
