Patent Grant
7341111
The present invention relates to bridge plugs of the type used to control fluid flow in a well. More particularly, the invention relates to an expandable bridge plug assembly for sealing within an existing tubular in a well to provide high reliability against inadvertent fluid flow past the bridge plug.
Bridge plugs have long been used in the oil and gas industry to control the flow of fluid through the well. A bridge plug commonly may employ resilient elastomeric sealing rings and anchoring slips, and may either seal off all flow through the well to isolate a lower interval from an upper interval in a well, or may be supplied with an internal passage or a choke to reduce or control flow through tubular at a desired depth.
A compression set bridge plug adaptable for through tubing operations is disclosed in U.S. Pat. No. 5,678,635. The anchor mechanism includes upper and lower independently movable slips. U.S. Pat. No. 4,436,150 discloses a bridge plug with an internal bypass passage which is closed when the bridge plug is set. The bridge plug includes external slips on a slip carrier. Bridge plugs are commonly hydraulicly or mechanically set. While various procedures have been employed for setting the bridge plug, sealing reliability between the bridge plug and the wall of the tubular in the well has been a significant problem, particularly when intended to seal off high pressure gas below the bridge plug.
The problems with the existing bridge plugs include poor reliability, particularly to seal gas in a well after the bridge plug has been set. In a subsea well, for example, tubular may be cut at or below the mud line and a bridge plug placed in the well to completely seal off the well. If gas bypasses the bridge plug, it bubbles to the surface and creates environmental hazzards. Accordingly, expensive remedial action must be taken to set another bridge plug in the well to stop the inadvertent flow of gas from the well.
The disadvantages of the prior art are overcome by the present invention, and an improved bridge plug assembly and method of setting a bridge plug in a well are hereinafter disclosed.
In one embodiment, a bridge plug and setting assembly are used to seal off fluid flow through a tubular in a well. One or more fluid powered units are provided for suspending in the well on a work string to exert a driving force, and a plug member having a closed end is suspended in the well below the one or more fluid powered units. An expansion sleeve is axially movable relative to the plug member in response to the driving force to radially expand the sleeve into sealing engagement with both the plug member and the tubular. A release mechanism is provided for releasing the one or more fluid powered units from the plug member and the expansion sleeve once set in the well. A flow passageway may be provided from the interior of the plug member to an annulus surrounding the power units. A bearing between the work string and the plug member facilitates rotation of the work string relative to the plug member. A ball seat at the lower end of the work string receives a ball to increase fluid pressure to the fluid power units, and releases the ball upon an increase in fluid pressure to drain the work string once a plug member and expansion sleeve are set in the well.
An advantage of the system and method of the present invention for setting a plug member in a well is the use of conventional components with high reliability. Existing personnel with a minimum of training may reliably use the system according to the invention.
These and further features and advantages of the present invention will become apparent from the following detailed description, wherein reference is made to the figures in the accompanying drawings.
A lower end 29 of the actuator sleeve 28 abuts the top of the expansion sleeve 40, and more particularly the upper head portion 32 of the expansion sleeve, as shown in
Expansion sleeve 40 includes a plurality of annular radially outer sealing members 42, and circumferentially spaced outer slips 44. The sealing members 42 provide a fluid tight seal with the interior of the tubular 12, and the slips 44 axially fix the expanded sleeve to the tubular.
When run in the well, its lower tapered end 46 of the expansion sleeve may thus be in engagement with the upper tapered surface 48 of the plug member 50, which includes a plurality of annular bumps 52 for reliable sealing engagement with the interior of the expansion sleeve once the plug member is set in the well. Plug member 50 may have various configurations, but in a preferred embodiment has a generally U-shaped construction, with a lower closed end 54 as shown.
The annular bumps could alternatively be provided on the ID of the expansion sleeve rather than on the OD of the plug member 50, although providing the bumps on the expansion sleeve may be less costly to manufacture.
Although not shown in
During the operation of setting the plug member, fluid pressure is increased within the work string and is thus supplied to the fluid powered units, connectors or pistons 16, 24 to exert a driving force by pushing upwards on the pistons 16 and downward on the pistons 24. Referring to
Once the plug member 50 is set in the well, fluid pressure may be increased to release the ball, as previously described. The work string 14 may then be rotated to the right, with the bearing 64 allowing the inverted cup shaped member 66 to remain stationary with the set plug member 50 while rotating the work string 14. Nut 68 is unthreaded by this right hand operation from the mandrel or work string, thereby detaching the work string and setting assembly from the set plug member and setting sleeve. With the nut 68 unthreaded from the plug member 50, the remaining apparatus may be retrieved to the surface, leaving the plug member 50 and the setting sleeve 40 reliably set in the well, as shown in
Various types of plug members may be used for control of fluid flow through a tubular. The plug member may completely block fluid flow once set in a well, or may include a restrictive aperture to allow controlled axial fluid flow through the set plug member, or may have a small diameter tubular passing axially through the bridge plug. The plug member need not be U-shaped, but may alternatively be a substantially solid and generally cylindrical shaped plug member.
In addition to left hand threads, various types of release mechanisms may be used for releasing the fluid powered units from the plug member and expansion sleeve once set in the well, including an axially movable collet mechanism. Other conventional release mechanisms include a releasable collet mechanism, a keeper which may engage and disengage a groove, or a releasable catch mechanism.
Although specific embodiments of the invention have been described herein in some detail, this has been done solely for the purposes of explaining the various aspects of the invention, and is not intended to limit the scope of the invention as defined in the claims which follow. Those skilled in the art will understand that the embodiment shown and described is exemplary, and various other substitutions, alterations and modifications, including but not limited to those design alternatives specifically discussed herein, may be made in the practice of the invention without departing from its scope.
| Number | Name | Date | Kind |
|---|---|---|---|
| 1945943 | Layne | Feb 1934 | A |
| 2178844 | Baker | Nov 1939 | A |
| 2715943 | True | Aug 1955 | A |
| 2813588 | O'Reilly | Nov 1957 | A |
| 3125162 | True | Mar 1964 | A |
| 3160209 | Bonner | Dec 1964 | A |
| 4436150 | Barker | Mar 1984 | A |
| 5678635 | Dunlap et al. | Oct 1997 | A |
| 6739398 | Yokley et al. | May 2004 | B1 |
| 6814143 | Braddick | Nov 2004 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 20060266529 A1 | Nov 2006 | US |
