Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02299765 2000-02-29
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TITLE OF THE INVENTION
Rod Puller
NAMES OF INVENTORS
Scott W. Widney
Richard L. Dedels
FIELD OF THE INVENTION
This invention relates to rod pulling/injection equipment and methods of rod
pulling and injection in wells.
BACKGROUND OF THE INVENTION
Various methods have been proposed for the handling of coiled rod in wells.
Corod of Canada has used a continuous chain system to inject coiled rod into
wells and
pull coiled rod out of wells. United States patent no. 5,992,516 of Palynchuk
et al,
2 0 issued November 30, 1999, shows a system in which clamps are moved on a
frame to
walk the coiled rod into and out of the well. This system works, but is
expensive to
build. The inventors have proposed a novel system of handling coiled rod that
is less
expensive and takes advantage of existing conventional rig equipment.
2 5 SUMMARY OF THE INVENTION
There is therefore proposed according to an aspect of the invention a rod
handling system for wells, comprising a wellhead, a rig having a mast, a
travelling
block suspended on the mast and a drive mechanism for the travelling block
arranged
to move the travelling block along the mast, an upper clamp secured to the
travelling
3 0 block, a lower clamp secured on the wellhead, and coiled rod extending
from a coiled
rod storage reel, through the upper clamp and lower clamp and into the
wellhead.
According to another aspect of the invention, there is proposed a method of
handling coiled rod in a well, comprising the steps of
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securing a lower clamp to a wellhead;
securing an upper clamp to a travelling block;
extending coiled rod from a storage reel through the upper clamp and lower
clamp; and
selectively gripping the coiled rod with one or both of the upper clamp and
lower clamp to guide the coiled rod into and out of the well.
According to an aspect of the invention, when coiled rod is injected into the
well, selectively gripping the coiled rod with one or both of the upper clamp
and lower
clamp comprises the steps of
a) gripping the coiled rod with the upper clamp;
b) releasing the coiled rod from the lower clamp;
c) lowering the travelling block downward a pre-determined distance;
d) gripping the coiled rod with the lower clamp;
e) releasing the upper clamp;
f) returning the travelling block upward to an initial position; and
2 0 g) repeating steps a-f until a desired depth has been reached with the
coiled rod.
According to a further aspect of the invention, when coiled rod is pulled from
the well, selectively gripping the coiled rod with one or both of the upper
clamp and
lower clamp comprises the steps of
a) gripping the coiled rod with the upper clamp;
2 5 b) releasing the coiled rod from the lower clamp;
c) pulling the travelling block upward a pre-determined distance;
d) gripping the coiled rod with the lower clamp;
e) releasing the upper clamp;
f) returning the travelling block downward to an initial position; and
3 0 g) repeating steps a-f until the coiled rod has been pulled up a desired
distance.
In either pulling or injecting, the upper clamp and lower clamp are released
from
the coiled rod only when the other of the upper clamp or lower clamp has
obtained 80%
of its full gripping pressure
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In other aspects of the invention: each of the upper and lower clamps
preferably
includes gripper blocks activated by respective cylinders to close on the
coiled rod. The
gripper blocks are preferably mounted on pivots to rotate into gripping
position on the
coiled rod or mounted for translational movement into gripping position on the
coiled
rod. The travelling block is preferably split to allow the coiled rod to pass
through the
travelling block. The coiled rod preferably passes through a guide terminating
adjacent
the travelling block, and the guide is secured to the mast of the rig (slant
or vertical).
These and other aspects of the invention are described in the detailed
description
of the invention and claimed in the claims that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
There will now be described preferred embodiments of the invention, with
reference to the drawings, by way of illustration only and not with the
intention of
limiting the scope of the invention, in which like numerals denote like
elements and in
which:
2 0 Fig. 1 is a side view of vertical rig equipment with a travelling block
and clamps
according to the invention;
Fig. 2 is a view of the equipment shown in Fig. 1 at right angles to the view
of
Fig. 1;
Fig. 3 is a side view of slant rig equipment with a travelling block and
clamps
2 5 according to the invention;
Fig. 3A shows a view of the slant rig of Fig. 3 from above at 45 degree angle
and shows the length of the clamping stroke;
Fig. 4 is a view of the equipment shown in Fig. 3 at right angles to the view
of
Fig. 1
3 0 Fig. 5 is a side view showing in more detail clamps used in the embodiment
of
Fig. 1;
Fig. 6 is a view at right angles to the view of Fig. 5 showing the clamps and
travelling block;
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Fig. 7A is a section through an embodiment of a clamp that could be used in
the
operation of the invention;
Fig. 7B is a section through the clamp of Fig. 7A along the line A-A;
Fig. 7C is a section through the clamp of Fig. 7A along the line B-B;
Fig. 8A is a section through another embodiment of a clamp that could be used
in the operation of the invention;
Fig. 8B is a side view of the clamp of Fig. 8A as shown by indicators A-A; and
Fig. 8C is a section through the clamp of Fig. 8 along the line B-B.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In this patent document, the word "comprising" is used in its non-limiting
sense
to mean that items following the word in the sentence are included and that
items not
specifically mentioned are not excluded. The use of the indefinite article "a"
in the
claims before an element means that one of the elements is specified, but does
not
specifically exclude others of the elements being present, unless, unless the
context
2 0 clearly requires that there be one and only one of the elements.
Figs. l and 2 show a conventional vertical rig 10 located in position to
inject
coiled rod into a well or pull coiled rod from a well through wellhead 12.
Apart from the
travelling block 14, rod guide 16, coiled rod 18 and clamps 22 and 24, the rig
10 is
conventional and includes a mast 20, the travelling block 14 suspended in
conventional
2 5 fashion from the mast 20 and a drive mechanism 26 for the travelling block
14 arranged
to move the travelling block 14 along the mast 20. The rig 10 may be a flush-
by, service
rig, drilling rig, or other rig having a travelling block and drive mechanism.
The
travelling block 14 may be conventional, but it is preferred to split the
travelling block
14 as shown in Fig. 1 to allow the coiled rod 18 to pass between the two sides
14a and
3 0 14b of the travelling block 14. This arrangement allows the coiled rod 18
to suffer
lower bending forces as it curves downward from rod guide 16 through the
travelling
block 14. The rod guide 16 is conventional as used in coiled rod applications,
except
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from the mast
20. The coiled rod 18 is supplied from a conventional carousel or storage reel
32.
Upper clamp 22 is secured to the travelling block 14 as for example by hanging
from the travelling block 14. Lower clamp is secured on the wellhead 12 as for
example
by screws. The coiled rod 18 extends from the coiled rod storage reel 32,
through the
upper clamp 22 and lower clamp 24 and into the wellhead 12.
Figs. 3 and 4 show the same equipment as shown in Figs. l and 2, except that
the rig is a slant rig 11 for use with a slant well 13, with slanted mast 21,
on which the
travelling block 14 slides along tracks 34 on the mast 21. The rod guide 36 in
this
system is provided with a swivel point 38 to accommodate the motion of the
travelling
block 14 along the tracks 34.
Figs. 5 and 6 show in more detail the location of the travelling block 14
upper
clamp 22, lower block 24 and wellhead 12. The upper clamp 22 hangs on hangers
39
from the travelling block 14. Upper clamp 22 is shown with gripper blocks 40
open,
while lower clamp 24 is shown with gripper blocks 40 closed.
2 0 Referring to Figs. 7A, 7B and 7C, an embodiment of the upper and lower
clamps 22, 24
is shown in which the gripper blocks 40a, 40b rotate about pivots 42a, 42b
respectively.
The exemplary clamp shown may be used for both upper clamp 22 and lower clamp
24.
The clamp is formed from a frame 44 with hanger ears 46 on opposite sides that
are
held by hangers 39 on the travelling block 14. The frame 44 has two sections
44a and
2 5 44b.
A first section 44a incorporates gripper blocks 40a, 40b that rotate about
pivots
42a, 42b secured to the frame 44. The gripper blocks 40a, 40b have gripping
surfaces 41
that are intended to minimize damage to the coiled rod 18. The surface is
described in
United States patent no. 5,992,516 issued November 30, 1999. Each gripper
block 40a,
3 0 40b is formed from a main block 48a, 48b which receives the pivot 42a, 42b
respectively. Extending from the blocks 48a, 48b are a pair of walls SOa, SOb
respectively which retain gripper pads 52a, 52b. The gripper pads 52a, 52b
each have a
slot 54 running down the length of the front surface 41 and cross-wise slots
56 cutting
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across the front surface 41. The cross-wise slots 56 become more closely
spaced
towards the downward end of the clamp, which permits a relatively uniform
stress
distribution. The slots 56 should be considerably thinner than the material of
the gripper
pads 52 between the slots 56. The walls 50 of one gripper block 40a should
extend
beyond the surface 41, while the walls 50 of the other gripper block 40b
should be
retracted. This construction helps to prevent walk out of the coiled rod 14.
The gripper
pads 52 are preferably mounted on the clamps 22, 24 such that they are readily
removable, as by bolting. The front surface 41 should have a sufficiently
smooth
surface, free of sharp teeth, or sharp edges, that well string gripped by the
gripping dies
is not damaged or scratched by the gripping dies during operation.
Frame section 44b houses a cylinder 60 which is used to activate the gripper
blocks 40a, 40b. The cylinder 60 is provided with drive fluid from a
conventional
source not shown. A piston rod 62 slides in the cylinder 60 and is connected
to the
gripper blocks 40a, 40b by a gripper block activating arm 64 and pivot arms 66
and 68.
The rod 62 is pivotally attached to the gripper block activating arm 64 at
pivot 70. One
2 0 end of the activating arm 64 is pivotally attached to pivot arm 66 at
pivot 72. An
intermediate part of the activating arm 64 located at an elbow 65 pivotally
attaches to
pivot arm 68 through a slot 74 through which runs a pivot pin 76. Pivot arm 66
is
pivotally attached to the frame section 44a at pivot 42a and to the gripper
block 40a at
pivot pin 78. Pivot arm 66 forms an acute angle. Pivot arm 68 is pivotally
secured to the
2 5 frame section 44a at pivot 42b and to the gripper block 40b at pivot pin
80. Pivot arm 68
forms an obtuse angle. As the rod 62 moves out of the cylinder 60, arm 64
moves to the
left in the Figs. 7A-7C, which rotates arm 66 counterclockwise and arm 68
clockwise,
which closes the gripper blocks 40a, 40b together to grip coiled rod between
them. The
gripper blocks 40a, 40b rotate into position against slips 82 which are
secured to the
3 0 frame 44a. Slips 82 ensure that any downward slippage motion of the
gripper blocks
40a, 40b tends to force the blocks together.
Refernng now to Figs. 8A, 8B and 8C, a further embodiment of a clamp is
shown that can be used as either the upper clamp 22 or lower clamp 24. The
clamp is
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formed from a frame 90 defined by side plates 92 and cross-pieces 94. A
cylinder 96 is
secured as by bolting between the side plates 92 and has a piston rod 98
extending out
from the cylinder 96. One gripper block 100 is mounted on an end of the piston
rod 98
remote from the cylinder 96 and another gripper block 102 is mounted in a
fixed
position, as by bolting, between the side plates 92. Gripper pads 104,
designed in the
same way as gripper pads 52, are secured in the gripper blocks 100 and 102.
The gripper
blocks 100, 102 are arranged so that at the full travel of the piston rod 98
to the right in
the drawing, the gap between the gripper pads 104 is slightly less than the
thickness of
the rod that is intended to be gripped by the gripper pads 104. Plates 106 are
secured to
the top and bottom of the gripper block 100 and extend beyond the side plates
92,
preferably on each side of the frame 90. An adjustable stop for the return
travel of the
gripper block 100 is formed by a stopper plate 108 that runs across the top of
the plates
92 from side to side between the cylinder 96 and the gripper block 100. The
stopper
plate 108 is mounted on pneumatic cylinders 110 secured to the plates 92 on
each side
of the frame 90. In normal operation, the movement of the piston rod 98 away
from the
2 0 rod being pulled or injected is restrained by the stopper plate 108. When
it is desired to
increase the range of movement of the gripper block 100, the pneumatic
cylinders 110
are activated to lift the stopper plate 108 off the plates 92 and allow
extended travel of
the gripper block 100.
The operation of the apparatus thus described is as follows. Continuous or
2 5 coiled rod is handled in the well by first securing the lower clamp to the
wellhead,
securing the upper clamp to the travelling block of a conventional rig,
extending coiled
rod from a storage reel through the upper clamp and lower clamp and
selectively
gripping the coiled rod with one or both of the upper clamp and lower clamp to
guide
the coiled rod into and out of the well.
3 0 For injection of coiled rod into the well, the clamp operation is as
follows:
a) gripping the coiled rod with the upper clamp;
b) releasing the coiled rod from the lower clamp;
c) lowering the travelling block downward a pre-determined distance;
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d) gripping the coiled rod with the lower clamp;
e) releasing the upper clamp;
f) returning the travelling block upward to an initial position; and
g) repeating steps a-f until a desired depth has been reached with the coiled
rod.
The upper clamp or lower clamp (as the case may be) is released from the
coiled
rod only when the other of the upper clamp or lower clamp has obtained 80% of
its full
gripping pressure.
For pulling of coiled rod from the well, the operation is as follows:
a) gripping the coiled rod with the upper clamp;
b) releasing the coiled rod from the lower clamp;
c) pulling the travelling block upward a pre-determined distance;
d) gripping the coiled rod with the lower clamp;
e) releasing the upper clamp;
f) returning the travelling block downward to an initial position; and
g) repeating steps a-f until the coiled rod has been pulled up a desired
distance.
As with injection, the upper clamp and lower clamp are released from the
coiled
rod only when the other of the upper clamp or lower clamp has obtained 80% of
its full
gripping pressure.
The above described clamps are preferably used in the method, so that
selectively gripping the coiled rod with the upper and lower clamps includes
activating
2 5 gripper blocks on the respective upper and lower clamps by respective
cylinders to close
on the coiled rod. The coiled rod passes through the split in the travelling
block for most
effective use.
Hydraulics for the operation of the clamps may be readily designed, and one
such design for the hydraulics is shown in United States patent no. 5,992,516
issued
3 0 November 30, 1999. The hydraulics need to be operated in conjunction with
the
operation of the travelling block on the rig.
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A person skilled in the art could make immaterial modifications to the
invention
described in this patent document without departing from the essence of the
invention
that is intended to be covered by the scope of the claims that follow.
