Patent Application
20050056429
The present invention relates in general to well tools and more specifically to a device and method for removing debris from the vicinity of a portion of a well tool and for improved operation of the well tool.
Well tools are operated in harsh downhole conditions often resulting in failure of the well tool to operate as intended. One cause of the failure is due to debris that exists in the well fluid. For example, many well tools include moveable mechanisms such as flapper type valves. These valves are positioned to be readily operated when needed.
However, it is all to common for debris contained in the well fluid to settle around the flapper preventing the flapper from opening or opening completely as desired.
Another problem encountered in existing well tools is failure of a moveable mechanism to operate due to pressure fluctuations in the well bore. These failures tend to occur more often in high downhole pressure environments with large diameter well tools. For example, often one shear pin bears an excessively load resulting in premature shearing of that pin and failure of the well tool to operate properly.
Therefore, it is a desire to provide a system and method for increasing the operational reliability of a well tool. It is a further desire to provide a debris removal system for removing debris from the vicinity of a portion of the well tool to alleviate jamming and tool failure. It is a still further desire to provide a dischargeable protection fluid for removal of debris from proximate a moveable mechanism of a well tool. It is a still further desire to provide an improved release mechanism for operating a well tool.
In view of the foregoing and other considerations, the present invention relates to well tools and more specifically to a system and method for removing debris from proximate a well tool.
Accordingly, a well tool protection system and method is provided. The system including a well tool having a housing forming a protection fluid chamber in fluid communication with a discharge port, a protection fluid disposed within the protection fluid chamber, and a moveable mechanism in functional connection with the protection fluid chamber in a manner to expel a portion of the protection fluid when the moveable mechanism moves.
The housing may be a part of the well tool or a member attached to an existing well tool. The housing may include a portion of the tubing or casing.
The discharge port may be positioned in any position wherein it is desired to remove debris from the vicinity of the well tool. For example, in a well tool, such as a flapper type formation or tubing isolation valve, it may be desired to position the discharge port proximate the back of the flapper. It may further be desired to include more than one discharge port. Additionally, it may be desired to design the discharge port to achieve a type of discharge fluid flow.
It may be desired for the moveable mechanism to include an operational feature of the well tool. In an embodiment of the present invention the moveable mechanism includes a slide sleeve that carries the flapper. When the slide sleeve is actuated to move downward the flapper may be moved from the closed to the open position. Utilizing the slide sleeve in functional connection with the protection fluid chamber, the protection fluid is expelled as the flapper is being opened alleviating jamming of the flapper by debris.
It has been further realized that well tools may fail when there is a pressure fluctuation in the well. The moveable mechanism spreads an uneven load across the shearing members resulting in premature shearing of a shearing member preventing movement of the moveable mechanism. Therefore it may be desired to include a first and a second sleeve in a moveable mechanism and additional breakaway or breakable members. Breakable or breakaway members include, but are not limited to, release mechanism such as collets as detents, shearable ratchets, shear pins, springs, c-rings, dogs, tension rods and other mechanisms known in the art. The sleeves may have ports that facilitate equalization of the pressures encountered in the well. In this manner uniform loads are spread across the breakaway members and a consistent and uniform release of the moveable mechanism is achieved.
A well protection system of the present invention may include a flapper, a housing having a protection fluid chamber in fluid communication with a discharge port positioned proximate the flapper, a protection fluid contained within the protection fluid chamber; a first slide sleeve positioned in moveable connection with the flapper wherein the first slide sleeve is held in a static position by a first breakable member; a second slide sleeve positioned in moveable relation to the first slide sleeve; a load support positioned below the second slide sleeve in a manner supporting the second slide sleeve in a set position; a retainer maintaining the load support in a set position, and a second breakable member maintaining the retainer in a set position.
A method of protecting a well tool allowing full and proper operation may include the steps of supporting a force from a pressure differential across a flapper when the flapper is in a closed position, actuating a first slide sleeve to move the flapper to an open position, parting a first breakable member allowing the first slide sleeve to move, equalizing the pressure differential across the flapper; parting a second breakable member releasing a second slide sleeve for movement, urging a second slide sleeve into movement by movement of the first slide sleeve, moving a load support, expelling the protections fluid, and moving the flapper to the open position.
The foregoing has outlined the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.
The foregoing and other features and aspects of the present invention will be best understood with reference to the following detailed description of a specific embodiment of the invention, when read in conjunction with the accompanying drawings, wherein:
Refer now to the drawings wherein depicted elements are not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views.
As used herein, the terms “up” and “down”; “upper” and “lower”; and other like terms indicating relative positions to a given point or element are utilized to more clearly describe some elements of the embodiments of the invention. Commonly, these terms relate to a reference point as the surface from which drilling operations are initiated as being the top point and the total depth of the well being the lowest point.
Well tool 12 is illustrated as a tubing isolation valve having a flapper 20. In
Slide sleeve 22 is positioned within protection fluid chamber 26. A protection fluid channel 28, or channels, is formed by a groove in slide sleeve 22. Protection fluid channel 28 has a discharge port 30 in fluid communication with chamber 26. Discharge port 30 may be positioned proximate pivot pin 24 such that protection fluid 16 will be discharged at the back 21 of flapper 20, as flapper 20 is being opened, to remove debris 25 and permit full movement of flapper 20 to the position shown by flapper 20a. It should be recognized that discharge port 30 may be positioned in various positions for debris removal. System 10 may include more than one discharge port. Discharge port 30 may be designed for the type of discharge flow desired.
Operation of debris removal system 10 of the present invention is now described with reference to
Since protection fluid channel 28 is formed on the same side of slide sleeve 22 as pivot pin 24, protection fluid 16 will only be discharged to the back of flapper 20. Protection fluid 16 will not have significant interaction with the well fluid getting into flow tube 38 through well fluid channels 46.
Debris removal system 10 shown in
Before flapper 20 is opened, there is a pressure differential across flapper 20, and the downward load caused by this pressure differential is taken by the load support members 48, which may include but are not limited to split rings. Seal 40 and seal 41 positioned in the outside diameter of flow tube 38 form a differential area. This differential area, with differential pressure, resists downward movement of second slide sleeve 23 until the pressure across flapper 20 is equalized. This minimizes the stress on flapper pin 24 and load support members 48.
Load support members, split rings 48, have a wedge face 70 and is installed in the groove 71 in flow tube 38.
Groove 71 in flow tube 38 also has a wedge face 72 to match the wedge face on split rings 48 to balance the load acting on split rings 48. Meanwhile, the radial load acting on split rings 48 from the ring wedge face 70 is balanced by the inner face 74 of retainer 50. Split rings 48 can be made by cutting a whole ring with a wedge face into multiple pieces along its axial direction. Once retainer 50 is moved away from split rings 48, split rings 48 will be free to be moved out of the groove of flow tube 38.
When operating well tool 12 from the closed to the open position, operating sleeve 32 is actuated to move downward urging moving member 18 including first slide sleeve 22 downward. As first slide sleeve 22 is urged downward the first shear pin 34a is sheared releasing first slide sleeve 22 for downward movement. Movement of first slide sleeve 22 downward opens the flow ports 42 in the second slide sleeve 23. The pressure across flapper 20 then equalizes and first slide sleeve 22 continues to move downward.
Because of the equalized pressure the split rings 48 and retainers 50 do not bear a high load. As the lower end 52 of first slide sleeve 22 contacts retainer 50 it breaks second shear pin 34b. As the first slide sleeve 22 continues to move downward its shoulder 54 urges the second slide sleeve 23 downward moving split rings 48 out of the groove 71 in flow tube 38. As slide sleeves 22 and 23 move downward protection fluid 16 is discharged through discharge port 30 urging debris 25 from the vicinity of flapper 20. As second slide sleeve 23 moves downward flapper seat 56 moves downward and tip 44 of flow tube 38 moves flapper 20 to an open position.
With reference to
From the foregoing detailed description of specific embodiments of the invention, it should be apparent that a debris removal system for clearing a moveable mechanism of a well tool and a release mechanism that is novel has been disclosed. Although specific embodiments of the invention have been disclosed herein in some detail, this has been done solely for the purposes of describing various features and aspects of the invention, and is not intended to be limiting with respect to the scope of the invention. It is contemplated that various substitutions, alterations, and/or modifications, including but not limited to those implementation variations which may have been suggested herein, may be made to the disclosed embodiments without departing from the spirit and scope of the invention as defined by the appended claims which follow. For example, the invention is described in relation to a flapper type valve such as in a formation isolation valve, tubing isolation valve or safety valve; however, the present invention may be incorporated into any well tools in particular well tools having moveable components.
This application claims benefit of priority from United States Provisional Application No. 60/503,024, filed Sep. 15, 2003 and entitled Well Tool Protection and Debris Removal, Release Mechanism, which is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 60503024 | Sep 2003 | US |
