Wells – Grapple and well anchored lifting means
Reexamination Certificate
1998-12-11
2001-03-06
Shackelford, H. (Department: 3671)
Wells
Grapple and well anchored lifting means
C166S099000, C166S178000, C166S301000, C294S086180, C294S086300
Reexamination Certificate
active
06196309
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an apparatus and method for retrieving objects from a well bore. More particularly, but not by way of limitation, the invention relates to a pulling tool and method for retrieving objects that are located within a well.
In the oil and gas industry, a well will intersect a subterranean hydrocarbon reservoir. The well will be completed to the reservoir, and the hydrocarbons will be produced to the surface. During the drilling, completion, and production of the well, operators will many times find it necessary to set various tools within the well. As those of ordinary skill in the art will appreciate, various devices are run into the well, set into the well, and later retrieved from the well. In order to run tools into the well, running tools that are commercially available from various manufacturers such as Camco and Halliburton are used. The devices set into the well may include valves, plugs, safety devices, and other tools.
In the event that the tool previously placed into the well requires removal, the operator will run into the well with a pulling tool. The pulling tool is used to retrieve the previously set device within the well and is commercially available from Camco, Halliburton and others. Nevertheless, when an operator attempts to retrieve a device from a well, the device may be difficult to pull. As those of ordinary skill in the art will appreciate, the operator may latch onto an object and experience a high degree of difficulty with retrieving the object/device. Even during normal retrieval operation, significant demands are placed on the integrity and strength of a pulling tool.
Sometimes, the amount of force required to dislodge the object overcomes the structural integrity of the pulling tool. In other cases, the object being pulled becomes in effect stuck in the well. Therefore, pulling tools have been designed so that the tool will shear off of the object at a predetermined force.
Prior art tools have been limited in the amount of pull force that can be applied to the pulling tool. The pull force will be limited by the structural design of the pulling tool. Therefore, there is a need for a tool that will allow for a greater pulling force to be exerted. There is also a need for a pulling tool that will allow for a greater force to be exerted in highly deviated and horizontal wells.
SUMMARY OF THE INVENTION
An apparatus for pulling objects from a well is described. The apparatus may comprise an elongated housing having an internal chamber. The housing will have means for connecting to the work string. The work string may include wireline, tubular, and/or coiled tubing. In the preferred embodiment, the work string will be wireline. A skirt is attached to the housing, with the skirt having an inner portion. The skirt will contain a first window and a second window therein, with the first window having a first shoulder thereon and the second window having a second shoulder thereon.
The apparatus further contains a mandrel disposed within the inner portion of the skirt, and a dog member disposed after the mandrel. The dog member has a first surface that cooperates with the first shoulder and a second surface that cooperates with the second shoulder. The apparatus also contains means, disposed about the mandrel, for biasing the dog member in a downward direction. The mandrel will have a first end and a second end, with the second end containing an angled shoulder. The dog member will contain an angled leg that is configured to cooperate with the angled shoulder of the mandrel. In the preferred embodiment, two dog members are used. When two dog members are used, the skirt contains a third and fourth window with a third shoulder and a fourth shoulder respectively.
In one embodiment, the apparatus will further comprise means for connecting the skirt with the mandrel. The first end of the mandrel contains a core nut attached thereto, with the core nut cooperating with the internal chamber of the housing to form a first spring chamber. The apparatus further comprises a first spring disposed within the first spring chamber, with the first spring acting to create a force against the core nut in an upward direction. The connecting means includes a shear pin that attaches the skirt to the mandrel such that as the shear pin is sheared, the mandrel is slidably received within the inner chamber of the housing. The biasing means may further comprise a spring, and a retaining ring disposed about the mandrel and cooperating with the spring to urge the dog member into engagement with the first shoulder and the second shoulder. Also, the mandrel may contain an inner bore, and the device may further include seal means, disposed about the mandrel, for sealing a fluid in the inner bore from the first spring chamber.
The device may be attached to a work string. The device comprises a tubular housing, a skirt attached to the tubular housing, the skirt containing a first and second window with shoulders thereon, a core being disposed within an inner bore of the skirt, with the core containing an end having an angled shoulder, a dog member disposed about the core, the dog member having a first end that cooperates with the first window and a second end that cooperates with the second window.
The method includes pulling upward on the wire line so that an upward force is created, and transferring the upward force to the tubular housing. Next, the upward force is transferred to the first window and the second window. The dogs are supported at the first shoulder of the first window and at the second shoulder of the second window. This allows distribution of the upward force to two points in the skirt. The operator may then provide a downward jarring force to the tubular housing. The core is contacted against the object, and a pin may be sheared so that the core is slidably disposed within the inner portion of the tubular housing. A core spring, located in a first spring chamber, is expanded which in turn lifts the core upward.
Next, the angled core end is engaged with an angled surface of the dog member which in turn lifts the dog member thereby expanding the dog member outward into the first window. The core is biased with the core spring located within the spring chamber. Thereafter, the core is moved upward within the inner portion. Next, the device is sheared and released from the object, and the device can be retrieved from the well bore.
An advantage of the present invention is the novel dog, support herein disclosed. Another advantage is the that the dogs are supported at two points in the skirt. Dogs in the prior art are supported at only one point in the skirt. Still yet another advantage is that the upward pull force is distributed to the skirt in two different locations.
A feature of the present invention is the use of a first and second dog member in the preferred embodiment that are extra wide so that approximately 50% of the fishing neck circumferential area is covered. Another feature is the ability to have a jar-up embodiment and a jar-down embodiment with essentially identical components. Also, in cases where it is not recommended to run a “jar down to shear” pulling tool, the operator has the ability to run the “jar-up to shear” pulling tool embodiment.
Another feature is that upon shearing of the pulling tool, the dogs are forced into the release mode by the angle on the top of the dogs being pushed up against the top shoulder in the windows and the mid section of the dog's inner surface being pushed out of the angled surface at the bottom of the core. There is a 1.5 degree difference between the longer surface of the mandrel and the upper inside surface of the two member dogs which facilitates member dog release from the object. The angle at the bottom of the mandrel is responsible for lifting the dogs and pushing the dog legs outward. Another feature is that the tool is designed so that after shearing, the two sheared ends of the pin can not be accidentally lost while pulling out of the well. Yet another feature is
Domingue & Waddell PLC
Shackelford H.
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