Anchoring tool

Details Anchoring tool Anchoring tool

1999-02-16

2001-02-20

Neuder, William (Department: 3672)

Wells

Expansible anchor or casing

Liner hanger

C166S117700, C166S242100

Reexamination Certificate

active

06189610

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to anchoring tools, and more particularly to devices for anchoring a tubing string to a surrounding well casing. Specifically the anchoring tool is for anchoring the tubing string against rotational and vertical displacement in relation to the well casing.
BACKGROUND OF THE INVENTION
Oil is commonly collected from below surface reservoirs using a tubing string. Typically the tubing string is constructed in threaded sections and includes an inline pump. The pump considered is a screw-type pump including a rotary drive, a stator and a screw type rotor rotatable therein. The pumps are commonly of right-hand rotation and under certain conditions can transmit large forces to the tubing string. This tends to rotate the tubing string and release the threaded sections which is undesirable.
This problem has been addressed by J. L. Weber in Canadian Patent No. 1,274,470, which discloses a “No-Turn™ Tool” for preventing such rotation of a tubing string. The device comprises an outer tubular housing which rotates about an inner mandrel. The housing holds four retractable slips which are extended for anchoring the device to the stationary well casing. Right-hand rotation of the inner mandrel relative to the housing engages cams which extend the slips into the well casing. Rotation in the opposite direction disengages the cams and the slips are pushed away from the well casing by springs. The device is relatively complex, using both springs and cams, resulting in significant manufacturing costs.
Also addressing the problem of rotation of a tubing string, U.S. Pat. No. 5,275,239 to M. Obrejanu discloses a device for anchoring a tubing string within a stationary well casing against right-hand rotation. The device has four anchoring mechanisms spaced circumferentially about a main housing. Each anchoring mechanism includes a recess and an anchoring member free-floating within the recess. A spring urges the anchoring member outward to engage the well casing. Right-hand rotation of the device will rotate the anchoring members into a locking position. The device is also complex, requiring a spring for each anchoring member. The anchoring members are free-floating and can jam, making the device less reliable.
SUMMARY OF THE INVENTION
The present invention is a simple, robust device with only one moving part improving upon the reliability of the previous art of preventing right-hand rotation of a tubing string.
According to a first aspect of the invention there is provided an anti-rotation device to prevent right-hand rotation for a tubing string within a stationary well casing, comprising:
a tubular housing for connection to the tubing string;
a fixed jaw mounted on the tubular housing for engaging the well casing;
two floating jaws for engaging the well casing; and
mounting means for mounting the two floating jaws on the tubular housing for free rotation about the housing.
According to a second aspect of the invention there is provided an anchoring device for anchoring a tubing string within a stationary well casing, the device comprising:
a tubular housing for connection to the tubing string;
a fixed jaw mounted on the tubular housing for engaging the well casing;
two floating jaws for engaging the well casing; and
mounting means for mounting the two floating jaws on the tubular housing for free rotation about the housing.
It is preferred that the mounting means comprises two collars which rotate freely about the tubular housing for mounting the floating jaws.
It is also preferred that the jaws project outwardly from the tubular housing and that outer edges of the jaws are configured for gripping the well casing.
The two collars may include a first collar rotating above the fixed jaw and a second collar rotating below the fixed jaw. The collars may also include stops which engage the fixed jaw to inhibit full rotation of the floating jaws.
There may be provided teeth on the jaws oriented to prevent rotational and vertical displacement of the device.
According to a further aspect of the invention there is provided an anti-rotation device to prevent right-hand rotation for a tubing string within a stationary well casing having a prescribed diameter with production tubing along the casing and the anti-rotation device connected to the tubing string, the device comprising:
a tubular housing for connection to the tubing string;
a fixed jaw projecting outwardly from the tubular housing and configured for gripping the well casing;
two floating jaws projecting outwardly from the housing and configured for gripping the well casing; and
mounting means for mounting the two floating jaws for free rotation about the tubular housing between a free position in which the floating jaws are positioned adjacent the fixed jaw and the overall diameter of the device is less than the diameter of the well casing and an engaged position with the floating jaws and the fixed jaw situated on opposing sides of the housing and the overall diameter of the device is greater than the diameter of the well casing.


REFERENCES:
patent: 4811785 (1989-03-01), Weber
patent: 4947944 (1990-08-01), Coltman et al.
patent: 5275239 (1994-01-01), Obrejanu
patent: 5829531 (1998-11-01), Hebert et al.
patent: 1274470 (1925-09-01), None

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