SNUBBING JACK

VERIN DE CURAGE SOUS PRESSION

English Abstract

A snubbing jack includes a first telescopic member and a second telescopic member. A stationary plate and a movable plate are affixed to the telescopic members. The movable plate moves away from the stationary plate upon expansion of the telescopic member and moves toward the stationary plate upon contraction of the telescopic members. An intermediate plate is removably secured between the stationary plate and the movable plate.

French Abstract

Vérin de curage sous pression comprenant un premier élément télescopique et un deuxième élément télescopique. Une plaque fixe et une plaque mobile sont fixées aux éléments télescopiques. La plaque mobile s'éloigne de la plaque fixe lors de l'expansion de l'élément télescopique et se rapproche de la plaque fixe lors de la contraction de l'élément télescopique. Une plaque intermédiaire est fixée de manière amovible entre la plaque fixe et la plaque mobile.

Claims

4
What is Claimed is:

1. A snubbing jack, comprising;
a first telescopic member and a second telescopic member;
a stationary plate affixed to the telescopic members;
a movable plate affixed to the telescopic members, the movable plate moving
away
from the stationary plate upon expansion of the telescopic member and moving
toward the
stationary plate upon contraction of the telescopic members; and
an intermediate plate secured between the stationary plate and the movable
plate,
wherein the intermediate plate is movable between a first position between the
stationary
plate and the movable plate and a second position withdrawn from between the
stationary
plate and the movable plate
2. The snubbing jack of Claim 1, wherein the intermediate plate is secured to
the telescopic
members.
3. The snubbing jack of Claim 1, wherein the movable plate and the
intermediate plate carry
slips.

Description

CA 02637330 2008-07-07
TITLE
Snubbing Jack
FIELD
There is described a snubbing jack which used on a well during a process
called
snubbing.

BACKGROUND
A conventional snubbing jack consists of a pair of hydraulic rams positioned
between
a stationary plate and a movable plate. Upon expansion of the hydraulic rams,
the movable
plate moves away from the stationary plate. Upon contraction of the hydraulic
rams, the
movable plate moves toward the stationary plate.

SUMMARY
There is provided a snubbing jack, comprising a first telescopic member and a
second
telescopic member. A stationary plate is affixed to the telescopic members. A
movable plate
affixed to the telescopic members. The movable plate moves away from the
stationary plate
upon expansion of the telescopic member and moves toward the stationary plate
upon
contraction of the telescopic members. An intermediate plate is secured
between the
stationary plate and the movable plate.

BRIEF DESCRIPTION OF THE DRAWINGS
These and other features will become more apparent from the following
description in
which reference is made to the appended drawings, the drawings are for the
purpose of
illustration only and are not intended to be in any way limiting, wherein:
FIG.1 is a front perspective view of a snubbing jack.
FIG. 2 is a front perspective view of the snubbing jack of FIG. 1 with a clamp
removed.
FIG. 3 is a front perspective view of the snubbing jack of FIG. 1 with the
intermediate plate withdrawn and the cap removed.

DETAILED DESCRIPTION


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2

A snubbing jack generally identified by reference numeral 10, will now be
described
with reference to FIG. 1 through 3.

Structure and Relationship of Parts:
Referring to FIG. 1, snubbing jack 10 has a first telescopic member 12 and a
second
telescopic member 14. A stationary plate 16 and a movable plate are affixed to
telescopic
members 12 and 14. Movable plate 18 is affixed to telescopic members 12 and 14
such that it
moves away from stationary plate 16 upon expansion of telescopic members 12
and 14 and
such that it moves toward stationary plate 16 upon contraction of telescopic
members 12 and
14 to perform snubbing operations. An intermediate plate 20 is secured between
stationary
plate 16 and movable plate 18. Intermediate plate 20 is also secured to
telescopic members
12 and 14, such that intermediate plate 20 is movable between a first position
between
stationary plate 16 and movable plate 18 as shown in FIG. 2 and a second
position withdrawn
from between stationary plate 16 and movable plate 18 as shown in FIG. 3.
Clamps 22 are
used to secure intermediate plate 20, such that, when one clamp 22 is removed,
the other may
be used as a hinge to remove intermediate plate 20. Referring to FIG. 3, clamp
22 is
supported vertically by an engagement profile on telescopic members 12 and 14.
Movable
plate 18 and intermediate plate 20 are designed to support slips (not shown)
used in snubbing
operations, while stationary plate 16 attached to, for example, a stripping
head 24 as depicted,
or other wellhead equipment, such as a blowout preventer, etc.

It will be understood that there may be other designs to allow intermediate
plate 20 to
be removably positioned between stationary plate 16 and movable plate 18. For
example,
there may be an attachment provided between stationary plate 16 and movable
plate 18, or a
combination of attachments. However, it has been found that the depicted
embodiment is
convenient as it allows intermediate plate 20 to be pivoted out of the way.

Operation:
Referring to FIG. 1, in operation, a tubing string (not shown) passes through
the
centre of plates 16, 18 and 20. In order to provide better access to the
snubbing jack, such as
for servicing requirements, the tubing string is moved out of the way, one of
the clamps 22 is
removed as shown in FIG. 2, and intermediate plate 20 is then pivoted out of
the way to allow


CA 02637330 2008-07-07
3

access to, in the example depicted, an RS stripping head 24 as shown in FIG.
3. In this
example, the RS stripping head cap 26 (shown in FIG. 1 and 2) may then be
removed, to
provide access to the sealing elements 28. As can be seen, the stationary
plate 16 is secured
to the neck of stripping head 26 by a multi-spiral retainer ring 30.
Advantages:
The design of snubbing jack 10 discussed above provides certain advantages.
For
example because intermediate plate 20 can be swung out of the way, and because
the slips are
carried by intermediate plate 20, it becomes easier to access certain elements
in the wellhead
equipment and/or the snubbing jack which require servicing.

In addition, while snubbing, the energy of the slips is applied to the bottom
surface of
intermediate plate 20 rather than on mounting bolts as is generally the case
in other snubbing
units. This reduces the chance of a thread failure, which could result in
losing control of the
tubing string.

In this patent document, the word "comprising" is used in its non-limiting
sense to
mean that items following the word are included, but items not specifically
mentioned are not
excluded. A reference to an element by the indefinite article "a" does not
exclude the
possibility that more than one of the element is present, unless the context
clearly requires that
there be one and only one of the elements.

The following claims are to understood to include what is specifically
illustrated and
described above, what is conceptually equivalent, and what can be obviously
substituted.
Those skilled in the art will appreciate that various adaptations and
modifications of the
described embodiments can be configured without departing from the scope of
the claims.
The illustrated embodiments have been set forth only as examples and should
not be taken as
limiting the invention. It is to be understood that, within the scope of the
following claims,
the invention may be practiced other than as specifically illustrated and
described.

Representative Drawing