Wells – Processes – Parallel string or multiple completion well
Reexamination Certificate
1999-04-30
2001-10-23
Neuder, William (Department: 3672)
Wells
Processes
Parallel string or multiple completion well
C166S117600
Reexamination Certificate
active
06305474
ABSTRACT:
RELATED APPLICATIONS
Not Applicable.
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to an apparatus for supporting and resisting rotation of a whipstock in a desired position in a well. More particularly, the present invention relates to a slip device that prevents rotation of the tool, and to a whipstock key that has a single locking orientation but provides axial supports at multiple azimuthal positions.
BACKGROUND OF THE INVENTION
Once a petroleum well has been drilled and cased, it is often necessary or desired to drill one or more additional wells that branch off, or deviate, from the first well. Such multilateral wells are typically directed toward different parts of the surrounding formation, with the intent of increasing the output of the well. Because the location of the target formation typically falls within a known azimuthal range, it is desirable to control the initial orientation of the deviation fairly precisely.
In order to drill a new borehole that extends outside an existing cased wellbore, the usual practice is to use a work string to run and set an anchored whipstock. The upper end of the whipstock comprises an inclined face. The inclined face guides a window milling bit laterally with respect to the casing axis as the bit is lowered, so that it cuts a window in the casing. The lower end of the whipstock is adapted to engage the anchor in a locking manner that prevents both axial and rotational movement.
It has been found that conventional whipstock supports may be susceptible to small but not insignificant amounts of rotational movement. Hence, it is desired to provide an anchor and whipstock setting apparatus that effectively prevent the whipstock from rotating. It is further desired to provide a system that can set the packer and anchor the whipstock in a single trip. It is further desired to provide an effective whipstock support that can be run in and set using conventional wireline methods.
Furthermore, in prior art devices, disengagement of the whipstock from the orienting key is typically prevented by a shear pin or similar device. The load capacity of this device limits the amount of load that can be placed on the tool. Hence, it is further desired to provide a key element that resists unintentional disengagement while allowing a greater downhole load to be supported by the tool.
In addition, relative rotation of the components of prior art devices is typically resisted by a key or straight spline. The separation of duties (orienting, resisting rotational movement, and resisting axial movement) in the prior art, and the performance of these duties by separate mechanisms resulted in a tool that was relatively complex and susceptible to a variety of failure modes. Hence, it is desirable to provide a tool that combines performance of these duties in, single, robust device.
SUMMARY OF THE INVENTION
The present invention provides an anchor and whipstock setting apparatus that effectively prevents the whipstock from rotating. According to a preferred embodiment, the present tool includes a frangible slip ring that includes a tongue-and-groove interface with the bottom sub of the tool, so as to resist rotation about the tool axis when the slips engage the casing. The tongue and groove interface provides a plurality of interface surfaces that can bear rotational loads and thus resist rotation better than previously known devices.
The present invention further provides a key, or scoop, that resists unintentional disengagement of the stinger from the key element. The preferred scoop includes a two part locking device that includes at least one, and preferably at least three, pin engaging slots. The preferred scoop comprises inner and outer concentric tubular members, each including at least one pin engaging slot. In this manner, the key element provides a single orientation, while simultaneously providing axial support at multiple points around the azimuth of the tool and allowing greater loads to be supported.
A further object of the present invention is to provide an apparatus that allows anchoring and orienting a whipstock in a well casing on a single trip of a running string into and out of the casing or using two trips with wireline tools.
REFERENCES:
patent: 5129453 (1992-07-01), Greenlee
patent: 5871046 (1999-02-01), Robison
patent: 6019173 (2000-02-01), Saurer et al.
patent: 2271791 (1994-02-01), None
patent: 2293187 (1996-03-01), None
patent: WO94/29563 (1994-12-01), None
Guillory J. Brandon
Roberts William M.
Neuder William
Smith International Inc.
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