1. Field of the Invention
The invention relates generally to fishing tools and methods for removing objects from a wellbore.
2. Description of the Related Art
Fishing tools are used to remove stuck objects from a wellbore. Typical fishing tools include a mechanical latch or set of collets which are intended to engage a lip or similar structure on a stuck object, or fish, to be removed. Difficulties arise when the fish is irregularly shaped or lacks a sufficient lip which would allow a conventional fishing tool to securely grip the fish.
The invention provides a fishing tool design which is useful for removing fish having irregular shapes and/or a lack of gripping structures to which a conventional fishing tool might be secured. An exemplary fishing tool is described which includes an overshot portion which defines an interior chamber.
The overshot portion of the fishing tool includes a gripping mechanism that will radially grip a fish or portion of a fish. The gripping mechanism includes a plurality of gripping segments which are moveably mounted to first and second end members. Rotation of the end members in opposite directions relative to one another will move the gripping segments radially inwardly or radially outwardly between a radially expanded configuration and a radially restricted configuration which is used for gripping a fish. Movement of the gripping members between radially expanded and restricted configurations may have an appearance similar to an iris surrounding a pupil in the eye.
The first end member is secured against rotation while the second end member is not secured against rotation. In described embodiments, the second end member presents a radially outwardly projecting lug which resides within a helical track in a surrounding sleeve so that downward axial movement of the second end member with respect to the sleeve will cause the second end member to rotate with respect to the first end member and the sleeve.
An alternative fishing tool is described in which movement of the gripping assembly with respect to the outer housing is controlled using a J-slot mechanism. In a described embodiment, the gripping assembly includes a J-slot ring from which an arm projects radially outwardly. A J-slot is inscribed within the outer housing. Axial movement of the gripping assembly with respect to the outer housing can only occur when the arm enters an axial leg of the J-slot.
For a thorough understanding of the present invention, reference is made to the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings, wherein like reference numerals designate like or similar elements throughout the several figures of the drawings and wherein:
In
Referring now to
Gripping assembly 34 includes a first end member 44 and a second end member 46. In currently preferred embodiments, the first and second end members 44, 46 are annular rings which have a central opening. However, other shapes might also be used. A central opening might be absent (for the first end member) or the member may have a non-circular shape. A plurality of gripping segments 48 is retained between the first and second end members 44, 46. A single gripping segment 48 is illustrated in
Each of the first and second end members 44, 46 contain a plurality of curved slots which are shaped and sized to receive the pins 60, 64 of the gripping segments 48 in a complementary manner and such that the respective pins 60, 64 can slidably move within them. The first end member 44 includes curved slots 68 which extend from a radially inner boundary 70 of the first end member 44 to a radially outer boundary 72 of the first end member 44. The second end member 46 includes curved slots 74 which also extend from a radially inner boundary 76 of the second end member 46 to a radially outer boundary 78 of the second end member 46. As depicted in
As can best be seen in
The first end member 44 of the gripping assembly 34 is secured to the tube 36 such that the first end member 44 will not rotate with respect to the tube 36 or within the outer housing 32. It is noted that the tube 36 may also be a rod, arm or other structure which is capable of securing the first end member 44 against rotation within the outer housing 32 and which is capable of moving the first end member 44 axially upwardly and downwardly within the outer housing 32. Preferably, the first and second end members 44, 46 are retained in a spaced relation to one another using a bracket or tie rod (not shown).
During operation, the fishing arrangement 20 is run into the wellbore 10 until the overshot portion 30 of the fishing tool 24 surrounds the reduced diameter portion 18 of fish 16. During run-in, the gripping assembly 34 is in the radially expanded configuration shown in
The gripping assembly 34′ includes first and second end members 44′, 46 and gripping members 48. First end member 44′ is preferably provided with a radially-projecting lug 108 which will reside within the helical track 42. A J-slot ring 110 is located axially above and is affixed to the first end member 44′. The J-slot ring 110 is an annular member from which an arm 112 extends radially outwardly. The arm 112 extends into the J-slot 102. Initially, the arm 112 is located within the semi-annular track 104 of the J-slot 102, as shown in
In operation, the fishing tool 100 is disposed into the wellbore 10 until the outer housing 32 of the fishing tool 100 contacts the fish 16. Weight is set down on the fishing tool 100 at surface to create a frictional engagement between the fish 16 and the outer housing 32. Tube 36 is rotated with respect to the outer housing 32 until the arm 112 of the J-slot ring 110 aligns with the axial leg 106 of the J-slot 102. The gripping assembly 34′ is then moved axially downwardly with respect to outer housing 32 as the arm 112 slides downwardly along the axial leg 106. This axial movement of the gripping assembly 34′ will cause the gripping members 48 to be moved radially inwardly to grip the reduced diameter portion 18 of the fish 16, as described previously.
Those of skill in the art will recognize that numerous modifications and changes may be made to the exemplary designs and embodiments described herein and that the invention is limited only by the claims that follow and any equivalents thereof.
Number | Name | Date | Kind |
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1454819 | Jones | May 1923 | A |
1582485 | Sauls | Apr 1926 | A |
1766177 | Langstaff | Jun 1930 | A |
1777592 | Thomas | Oct 1930 | A |
1788912 | Corey | Jan 1931 | A |
1825025 | Thomas | Sep 1931 | A |
1825026 | Thomas | Sep 1931 | A |
2061864 | Wells | Nov 1936 | A |
2072338 | Kelso | Mar 1937 | A |
2075248 | Wickersham | Mar 1937 | A |
2427438 | Breaux | Sep 1947 | A |
2737410 | Stohn | Mar 1956 | A |
4101157 | Richey | Jul 1978 | A |
5054833 | Bishop | Oct 1991 | A |
20030205377 | Streater | Nov 2003 | A1 |
Number | Date | Country | |
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20180209234 A1 | Jul 2018 | US |