Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02854409 2014-06-16
QUARTER TURN TORQUE ANCHOR AND CATCHER
FIELD OF THE INVENTION
The present invention relates to tools for oil and gas wells generally,
including
wells accessing heavy crude, and in particular relates to a torque or tubing
anchor
(collectively herein a tubing anchor) and catcher for anchoring from rotation
and linear
movement, and catching well equipment, such as a progressive cavity or rod
pump, and
related tubing string in a well conduit.
BACKGROUND OF THE INVENTION =
Known tubing anchors, also referred to as anchor catchers, use either a
combination of right and left hand threads, or are limited to one thread
orientation.
Examples of such tubing anchors are shown in US patent no. 3,077,933 to
Bigelow and in
Canadian patent no. 933,089 to Conrad. Disadvantages of such tubing anchors
include
the expense of manufacturing the threaded portions, and the stop pins are
vulnerable to
breakage during use.
Another type of tubing anchor shown in US patent no. 5,771,969 and
corresponding Canadian patent no. 2,160,647 to Garay avoids the aforementioned
threads
and instead uses a helical bearing to transform rotational movement into
linear movement
CA 02854409 2014-06-16
for setting and unsetting the tubing anchor. The helical bearing also
accommodates shear
pins for secondary unsetting if required. The use of one component, namely the
helical
bearing, to perform several functions has the advantage over the previous
prior art of
being less expensive to manufacture and less susceptible to breakage.
However, there is a need for a tubing anchor that further improves on these
prior
designs. In particular, there is a need for a tubing anchor that avoids the
prior art threads
and helical bearings that require one or more full (i.e. 360 degree) rotations
of the tubing
anchor's mandrel to either set or unset the tubing anchor. The tubing anchor
should not
need to translate rotational movement into linear movement to engage the
anchor slips
with the well conduit, but rather should directly transfer a short
longitudinal movement of
the mandrel to extend the slips into gripping engagement with the well
conduit. The
tubing anchor should require only a limited rotation, such as a quarter turn,
of the
mandrel in a first direction to set the tubing anchor, and to help maintain
the anchor in the
set position by merely pulling tension on the mandrel via the tubing string.
One or more
tracks in the mandrel, each formed by a groove having joined longitudinal and
transverse
arms, should guide a corresponding drive pin to achieve the desired
longitudinal and
rotational movements. The groove's arms should be relatively short to reduce
both
manufacturing costs and the risk of debris entering the groove to interfere
with proper
operation. The tubing anchor should have a secondary unsetting capability
where release
2
CA 02854409 2014-06-16
is achieved by merely pulling the mandrel at a predetermined force to sever
certain
fasteners mounted to the mandrel.
SUMMARY OF THE PRESE'N'T INVENTION
A tubing anchor for anchoring well equipment in a well conduit to arrest
movement in both longitudinal directions and rotation in a first direction
includes:
a mandrel connected to said well equipment;
a first cone element slidably mounted to said mandrel and having a first
conical
surface;
a drag body slidably mounted on said mandrel, housing a drag or a drag means
for
contacting said well conduit, and having a second cone element having a second
conical
surface;
a slip retainer mounted on said mandrel housing at least one slip, each slip
having
an inner surface, and an opposed outer surface for gripping said well conduit,
and a
biasing device or biasing means for urging said slip inwardly toward said
mandrel and
away from said well conduit;
at least one pin connected to said drag body and a portion of said pin
protruding
toward said mandrel; and,
said mandrel having at least one groove for slideably receiving said
protruding
portion of said pin in sliding relation on a corresponding groove;
3
CA 02854409 2014-06-16
_
and wherein said groove has at least one longitudinally extending portion and
at least one
lateraly extending portion contiguous with and extending laterally of said at
least one
longitudinally extending portion, wherein said at least one longitudinally
extending
portion extends along said mandrel and said at least one laterally extending
portion
extends at least partially around said mandrel,
wherein said pulling of said mandrel translates said pin to an end of said at
least
one longitudinally extending portion of said groove so as to said cause said
pin, and in
turn saidiad second conical surface of said drag body, to move toward said
first cone
element,
and further comprising .at least one spring configured to resiliently urge
said first cone
element towards said second conical surface to thereby provide a catcher,
wherein a
release of said tension caused by a break in said well equipment drives said
spring, and
thereby said first cone element, so as to engage said inner surface of each
said slip and
tosaid drive each said slip outward to said grip the well conduit.
In the preferred embodiment the at least one longitudinally extending portion
includes
laterally spaced apart first and second longitudinally extending portions, and
the at least
one laterally extending portion includes longitudinally spaced apart first and
second
laterally extending portions interleaved with said first and second
longitudinally
4
CA 02854409 2014-06-16
extending portions, so as to provide a sequence in said groove of said first
longitudinally
extending portion, said first laterally extending portion, said second
longitudinally
extending portion, and said second laterally extending portion. Also in the
preferred
embodiment, the first and second laterally extending portions of said groove
require, for
said portion of said pin to follow along said groove, that said mandrel be
turned in
reverse first and second corresponding directions about said axis of rotation.
By way of
example, said at least one laterally extending portion extends at least
substantially a
quarter of a circumferential distance around said mandrel; that is,
substantially a quarter
turn of the mandrel.
When said mandrel is viewed in vertical elevation, the groove is shaped as
substantially a
C-shape or a reversed C-shape depending fon the vertical orientation of the
mandrel
when so viewed, and direction of turn of the pump in the string. Thus, if the
pump in the
string turns to the left, when viewed from above, the mandrel is turned
clockwise to the
right, then left to move the pin along the groove. Unset or release is then a
right turn of
the mandrel. If the pump turns to the right, the mandrel is turned left then
right, that is,
in miror image, and the release is a turn to the left.
In embodiments with a plurality of drive pins, a corresponding a plurality of
said grooves
are radially spaced around the circumference of said mandrel.
5
CA 02854409 2014-06-16
In one embodiment the, at least one pin is a drive pin adapted to shear off to
provide a
secondary release when said mandrel is pulled in tension in excess of a
failure shear
resistance of said at least one pin. In other embodiments, separate shear pins
are
provided as a secondary release.
In a method of anchoring well equipment in a well conduit to arrest movement
in both
longitudinal directions and rotation in a first direction, and to allow
rotation in an
opposite second direction, using a tubing anchor and catcher having:
a mandrel connected to said well equipment, said mandrel having a longitudinal
axis of rotation;
a first cone element slidably mounted on said mandrel, said first cone element
having a first conical surface;
a drag body slidably mounted on said mandrel, a drag coupled to said drag body
and sized to drag against said well conduit, said drag body having a second
cone element
having a second conical surface;
a slip retainer mounted on said mandrel, said slip retainer housing at least
one
slip, each slip having an inner surface, and an opposed outer surface for
gripping said
6
CA 02854409 2014-06-16
well conduit, and a biasing device urging each slip inwardly toward said
mandrel and
away from said well conduit;
at least one pin connected to said drag body and having a portion of said pin
protruding toward said mandrel; and,
said mandrel having at least one groove slideably receiving said protruding
portion of said pin in sliding relation in said groove;
wherein a tension applied to said well equipment causes an initial pulling on
said
mandrel which causes said pin, and in turn said second cone element to move
toward said
first cone element so that said second conical surface of said drag body
contacts said
inner surface of each said slips and urges said inner surface of each said
slip to contact
said first conical surface of said first cone element so that said first and
second conical
surfaces drive each said slip outward so that said outer surfaces of each said
slip grips
said well conduit,
and wherein said groove has at least one longitudinally extending portion and
at least one
lateraly extending portion contiguous with and extending laterally of said at
least one
longitudinally extending portion, wherein said at least one longitudinally
extending
7
CA 02854409 2014-06-16
portion extends along said mandrel and said at least one laterally extending
portion
extends at least partially around said mandrel,
wherein said pulling of said mandrel translates said pin to an end of said at
least
-- one longitudinally extending portion of said groove so as to said cause
said pin, and in
turn said second conical surface of said drag body, to move toward said first
cone
element,
and further comprising at least one spring configured to resiliently urge said
first cone
-- element towards said second conical surface to thereby provide a catcher,
wherein, a
release of said tension caused by a break in said well equipment drives said
spring, and
thereby said first cone element, so as to engage said inner surface of each
said slip and
drive each said slip outward to said grip said well conduit,
is -- wherein said at least one longitudinally extending portion includes
laterally spaced apart
first and second longitudinally extending portions, and wherein said at least
one laterally
extending portion includes longitudinally spaced apart first and second
laterally
extending portions interleaved with said first and second longitudinally
extending
portions, so as to provide a sequence in said groove of said first
longitudinally extending
-- portion, said first laterally extending portion, said second longitudinally
extending
portion, and said second laterally extending portion,
8
CA 02854409 2014-06-16
wherein said first and second laterally extending portions of said groove
require, for said
portion of said pin to follow along said groove, that said mandrel be turned
in reverse
first and second reverse directions about said axis of rotation,
wherein said method comprises:
exerting an initial pull on said mandrel to move said pin along said
longitudinally
extending portion of said groove to extend said slips to grip said well
conduit; and,
then rotating said mandrel in said first direction to move said pin along said
first
laterally extending portion of said groove to set said tubing anchor, then
exerting a
further pull on the mandrel followed by a reverse turn of said mandrel, after
said rotation,
so as to move said pin along said second longitudinally extending portion and
said second
laterally extend portion respectively to maintain said tubing anchor in said
set position.
The msetting of said tubing anchor comprises reversing the steps to extend
said slips and
set said anchor. A secondary unsetting of said tubing anchor comprises
increasing said
further pull on said mandrel until the failure shear resistance of said pins
is exceeded.
9
CA 02854409 2014-06-16
BRIEF DESCRIPTION OF THE DRAWING FIGURES
Embodiments of the invention will now be described, by way of example only,
with reference to the accompanying drawings, wherein:
Figure 1 is a side view of a tubing anchor according to a preferred embodiment
of
the present invention, shown in a run (unset) orientation;
Figure 2 is a perspective view, in isolation, of a mandrel of the tubing
anchor of
fig. I
Figure 3 shows the tubing anchor of fig. 1 in a run position within a segment
of
well conduit shown in trasparent view;
Figure 3a is a cross-sectional view of the tubing anchor and well conduit
along
line 3a-3a of fig. 3;
Figure 4 shows the tubing anchor and well conduit of fig.3 with a partially
transparent view of a drag body housing;
Figure 4a is a close up view of the circle area 4a of fig. 4;
CA 02854409 2014-06-16
Figure 5 is a longitudinal section through the tubing anchor and well conduit
of
fig. 3, generally along the line 5-5;
Figure 6 shows a set position of the tubing anchor of fig.3 in the conduit;
Figure 6a is a cross-sectional view of the tubing anchor and well conduit
along
line 6a-6a of fig. 6;
Figure 7 is a longitudinal section through the tubing anchor and well conduit
of
fig. 6, generally along the line 7-7;
Figure 8 is an elevation view of the tubing anchor in a further embodiment
providing a catcher and improved mandrel grooves, showing a slim-hole
embodiment in
it's run-in position with the slips retracted;
Figure 8a is, in cross-section, the tubing anchor and catcher of figure 8;
Figure 8b is the sectional view of Figure 8a showing the anchor in its set
position
with the slips extended;
11
CA 02854409 2014-06-16
Figure 9 is, in perspective view, the mandrel of Figure 8 showing the improved
mandrel grooves spaced around the mandrel;
Figure 9a is an enlarged view of the mandrel grooves of Figure 9, showing a
pin
from the drag body engaged in one of the grooves, in the run-in position;
Figure 9b is the view of Figure 9a showing the pin in the anchor set and
locked
position;
Figure 10a and 10b are section views of a heavy crude embodiment of the tubing
anchor and catcher of Figure 8, in the run-in and anchor set positions
respectively;
Figure 11 is an elevation view of the tubing anchor and catcher in a further
embodiment proving shear pins between the slip retainer and drag blocks;
Figure 11 a is sectional view along the lines ila -11a in Figure 11; and,
Figure 12 is, an exploded view, the tubing anchor and catchor of Figure 11.
Figure 12a is an enlarged view of a portion of Figure 12.
12
CA 02854409 2014-06-16
_ .
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring first to figures 1 to 5, a preferred embodiment of a tubing anchor,
generally indicated by reference numeral 10, is shown inserted within a well
conduit 12,
such as a wellbore casing. The tubing anchor is shown in an unset, or "run-
in",
orientation in which it can be run inside the well conduit on a tubing string,
along with
other well equipment 14, such as a safety sub, attached above and below. In
particular,
the well equipment is attached to a cylindrical mandrel 20 having attachment
means, such
as an inner threaded lower end 22 and an outer threaded upper end 24. In this
embodiment, the tubing anchor is run down the well conduit on the tubing
string in the
direction indicated by arrow 16. It is noted, however, that terms such as
"up", "down",
''forward", "backward" and the like used to identify certain features of the
tubing anchor
when placed in a well conduit is not intended to limit the tubing anchor's use
or
orientation. Further, when decribing the invention, all terms not defined
herein have their
common art-recognized meaning.
The tubing anchor has a tubular drag body 40 mounted over the mandrel 20 to
house a drag means in the form of multiple drag blocks 42 for spacing the
tubing anchor
away from the inner wall 13 of the conduit 12. In the preferred embodiment
drag blocks
42, for example, three or four drag blocks 42, are generally evenly spaced
circumferentially about the tubing anchor. Each drag block 42 has a drag
spring 44 to
13
CA 02854409 2014-06-16
urge the outer surface 46 of the drag block against the conduit's inner wall
13. Upper and
lower drag retaining rings 48, 50 keep the drag blocks 42 removably mounted
within the
drag body 40. At least one lower cap screw 52 attaches the lower retaining
ring 50 to the
drag body 40. For illustrative purposes, fig. 3a shows the use of three
circumferentially
staggered cap screws 52. In addition to keeping the tubing anchor spaced from
the
conduit, the contact of the drag block surface 46 with the conduit's inner
wall 13 causes
friction that urges the drag body 40 to remain stationary while the mandrel 20
moves
within.
A tubular slip retainer 60, or slip cage, mounted on the mandrel 20 adjacent
the
drag body 40 houses a plurality of radially movable slips 62. In the drawings
three slips
62 are shown generally evenly spaced about the drag body, although this is not
intended
to be limiting as the anchor described herein may conceivably be made to
operate with
only one slip 62. Each slip has an outer surface 63 with teeth for gripping
the conduit
wall 13 upon contact, and an inner surface with opposed outwardly inclined
edges 64. A
fastener in the form of a socket head cap screw 65 is fastened to the drag
body 40 and is
located within each of a plurality of elongate slots 66 spaced
circumferentially about the
slip retainer, preferably between each slip. The cap screw 65 is adapted to
contact the
upper and lower shoulders 68a, 68b at the ends of the slot, which form stop
means to
prevent the slip retainer 60, and the drag body 40, from moving off the
mandrel 20.
14
CA 02854409 2014-06-16
A cone element 70 at an upper end of the slip retainer is mounted to the
mandrel
20 by a plurality of circumferentially spaced fasteners in the form of shear
screws 72.
Screws 72 also act as shear pins to release the tubing anchor from a set
position upon
exertion of sufficient tension on the well equipment, as will be discussed
later. The edge
of the cone 70 opposite the screws 72 forms a first conical surface 74 whose
inclined
surface wedges under the slips 62 when the tubing anchor is moved into a set
position.
Likewise, an upper edge of the drag body 40 forms a second conical surface 54
whose
inclined surface concurrently wedges under the slips 62 when the tubing anchor
is moved
into a set position. However, the first and second conical surfaces 74, 54
should not
io actively contact the slips in the unset position, as shown in fi,g.5. A
biaser in the form of
a slip spring 76 urges each slip 62 radially inwardly into the slip retainer
and away from
the well conduit 12 in the unset position (fig.5).
At least one groove 80 is formed in the mandrel's outer cylindrical surface
26,
best seen in fig.2. The L-shaped groove has a first or upper arm 82 extending
longitudinally with a shoulder 83 at its upper end forming a stop and an elbow
81 at its
lower end. A second or lower arm 84 extends circumferentially from the elbow
81 at a
generally right angle to the upper arm 82. A terminal end 86 of the lower arm
forms
another stop and has opposed indents 86a, 86b extending longitudinally
upwardly and
downwardly therefrom. The groove 80 is dimensioned (width, depth) to slidingly
accommodate a protruding portion of a drive pin 88 extending therein threaded
through a
CA 02854409 2014-06-16
hole 56 in an lower part of the drag body 40 so as to slidably engage in
groove 80 (fig.5).
The lower retaining ring 50 keeps the drive pin 88 within the drag body 40 and
engaged
within the groove 80. In the fig. 3a embodiment, not intended to be limiting,
three sets of
grooves 80 and drive pins 88 are shown generally evenly radially spaced about
the
mandrel.
The operation of the tubing anchor may now be described including figures 6 to
7
showing the tubing anchor in the set position in the well conduit 12. In the
embodiment
of figures 1-7 there are generally two steps for moving the mandrel 20 in a
"setting
direction" to the set position, and a third step to help lock, fix or maintain
that set
position. The first step is to initially pull the mandrel upwardly by lifting,
that is,
tensioning the tubing string 14 in the direction of arrow 17, so that each
drive pin 88
travels downwardly along the first awl 82 of the respective groove to the
elbow 81
(fig.2). In this embodiment that travel is relatively short, approximately 2.5
mm (about
1.0 inch). The pull on the mandrel forces the drive pins 88 to push the drag
body's
second conical surface 54 toward the first conical surface 74 of the cone
element 70. As
these two components converge, the conical surfaces contact the inner edges 64
of each
slip 62 to drive the slips outwards, so that the slip's outer surface 63
contacts and bites
into the well's inner wall 13. As a result, the mandrel 20 and the attached
well equipment
are fixed such that they can not move longitudinally in the well either up or
down. At
this point the second step is to turn the tubing string to the right (i.e.
clockwise when
16
CA 02854409 2014-06-16
looking down the tubing string in the direction of arrow 16, in this
embodiment)
approximately "a quarter turn" (i.e. about 90 degrees) so that each drive pin
88 travels
along the lower arm. 84 from the elbow 81 to the stop 86. At this point the
mandrel and
tubing string should be rotationally fixed in this first, or clockwise,
setting direction. And
finally the third step is to maintain the tubing anchor in this set
orientation by continuing
to pull tension on the tubing string straight up in direction 17, which should
also engage
the drive pin 88 with the lower indent 86b which secures the pin upon entry to
aid in
maintaining the set position. The drill string should be kept in tension as
long as the set
position is desired. This description is suited for the situation where the
pump in the drill
string is a rod pump. In embodiments where the pump turns to the right, for
example in
the case of a progressive cavity pump system, the mandrel locking movement
would be
reversed, that is, the mandrel is moved upwards then left and the
corresponding groove
shape would also be reversed, i.e., a 3-shape as opposed to an L-shape,
collectively
referred to herein as an L-shape.
The tubing anchor is released, or unset, by reversing the above described
setting
procedure. The first =setting step requires release of tension by moving the
tubing
string, and hence the mandrel 20, down somewhat, which should move the drive
pins 88
out of the corresponding lower indents 86b to the upper indents 86a which
temporarily
"store" the pins on exit. The second step requires rotating the tubing string
and mandrel
in a second direction opposite to the setting rotation, namely turning to the
left (i.e,
17
CA 02854409 2014-06-16
counter-clockwise when looking down the tubing string in the direction of
arrow 16, in
this embodiment) approximately "a quarter turn" so that each drive pin 88
travels from
the upper indents 86a along the lower arm 84 to the elbow 81. Finally, in a
third step, the
mandrel should be moved further down relative to the drag body so that the
drive pin 88
travels up the upper arm 82 from the elbow 81 toward the stop 83. After the
pin reaches
this stop, continuing this mandrel movement causes the drag body 40 to move
downwards, and thereby the second conical surface 54 to move away from the
inner edge
64 of each slip 62. The springs 76 urge the respective slips 62 inwardly away
from the
well's inner wall 13, thus releasing the tubing anchor for movement
longitudinally (both
up and down the well) and rotationally (in the unsetting direction). This
allows the
tubing anchor to be moved to a different position in the well conduit 12 and
be set again,
or to lift the tubing anchor and remove it from the well conduit.
An alternate method of =setting the tubing anchor is to pull tension on the
tubing
string to exert sufficient upward force on the mandrel 20 to shear the shear
screws 72 by
=
exceeding their maximum shear resistance. Once the shear screws 72 are
sheared, the
cone element 80 becomes detached from the mandrel 20 and is free to move away,
namely upward, from the slips 62, allowing the springs 76 to retract the slips
away from
the inner surface 13 of the conduit. The torque ancher is therefore freed for
removal from
the well conduit 12. The maximum shear resistance may be "adjusted" by either
changing the shear screws 72 to ones with a different shear value, or by
altering the
18
CA 02854409 2014-06-16
number of shear screws inserted into the cone element 80. For instance, in one
version of
the tubing anchor, twelve brass screws 72 can be employed each with about 5000
pounds
(2273 kg) resistance, and their 1118XimlITTI shear resistance does not exceed
that of the
drive pins 88 to avoid damaging the pins during such secondary release of the
tubing
anchor.
The tubing anchor 10 is thus designed to anchor the tubing string from
movement longitudinally along the well (in both directions, up and down the
well) and
from rotation (in the setting direction). The anchoring is achieved by simple
setting and
release procedures with relatively little movement of the tubing string. In
this instance,
setting is achieved by a small pull of the mandrel (via the tubing string)
that is adequate
for the drive pin 88 to travel the short distance along the longitudinal arm
82 to reach the
elbow 81, and then by a small "quarter" turn of the mandrel that is adequate
for the drive
pin 88 to travel the short distance along the circumferential arm 82 to reach
the toe 85,
and finally by further pulling to engage the drive pin 88 with the lower
indent 86b. The
tubing anchor 10 avoids the more labourious and time consuming multiple full
rotations
of the mandrel that are currently required to set a tubing anchor. The
relatively short L-
shaped groove 80, in comparison to the multiple twists of the long threads or
helical
groove of other mandrels, reduces the risk of foreign objects obstructing the
drive pin's
travel path, and thus should improve the tubing anchor function, reliability
and wear.
Also, since this anchoring is achieved by placing the tubing string in
tension, there is an
19
CA 02854409 2014-06-16
added benefit of ensuring that the tubing follows the rod string as closely as
possible,
which helps minimize rod wear.
Some further benefits are set out below.
The configuration of the tubing anchor, including the arrangement of the set
screws with a given shear resistance below that of the drive pins 88, provides
a relatively
fast and easy secondary unsetting of the tubing anchor in case of an emergency
or should
a problem be encountered with the primary means of setting and unsetting via
the
L-
shaped groove 80.
Referring to fig. 613, the slips 62 are configured not only to centre the
tubing
anchor within the well conduit 12, but radially protrude sufficiently from the
slip retainer
60 to provide large by-pass spaces 78 between the tubing anchor and the
conduit, creating
high flow areas for fluids (eg. gas) and solids (eg. sand) to pass by the
tubing anchor, and
allowing coil tubing to more easily extend past the tubing anchor, than other
tubing
anchors. In the fig. 6b version, for instance, by-pass spaces 78 with 1.0 inch
(25.4 mm)
radial clearance are created between the 4.5 inch (114.3 mm) OD of the slip
retainer 60
and the 6.5 inch (165.1 mm) ID of the well conduit 12.
The configuration of the tubing anchor 10 permits capillary cable to be
carried
downhole via the large by-pass spaces 78 created by this novel tubing anchor
design. In
CA 02854409 2014-06-16
particular, the fact that the tubing anchor 10 is set and unset by
longitudinal motion and a
limited, quarter turn, permits its use with the capillary cable since the
anchor stays
relatively straight during use, thus avoiding wrapping of the cable around the
anchor. In
contrast, prior art anchors that require multiple full (360 degree) rotations
¨ between two
to seven full rotations for setting and =setting ¨ cause an undesireable
wrapping of the
cable around the anchor, which damages the cable. Alternately, the cables must
be pre-
wrapped when inserted with these prior art anchors, so that they unwrap as the
anchor is
twisted during setting, which is tedious and undesireable.
The drag blocks 42 have been hardened, over prior art drag blocks, for longer
life.
The slips 62 are made of solid high strength metal for superior durability and
grip on the
well conduit wall 13, and InconelTM type springs 76 are employed for improved
resistance to I-12S and CO2. Further, the surface of the mandrel 20 is
optionally coated
with Teflon for improved resistance to H2S and CO2, and to help maintain
mandrel
strength.
In the alternative embodiments of Figures 8 ¨ 10b, a version of anchor tool
that
also serves as a catcher is illustrated. The embodiment of Figures 8 ¨ 10b
also illustrates
an improved groove configuration that replaces the L-shaped groove 80 of
Figure 2.
21
CA 02854409 2014-06-16
_
Applicant has determined that in some circumstances improved locking of the
slips 62 in their set position is desirable, for example in circumstances
where the pump is
causing excessive vibration sufficient to potentially un-set the slip over
time when using
the L-shape groove embodiment of Figures 1-7. Consequently groove 180 best
seen in
figures 9a, 9b provides increased security for locking pin 88 in its set
position.
As seen in Figure 9a, which is an enlarged view of groove 180 in Figure 9, the
portion 88a of pin 88 which protudes into groove 180, seats against shoulder
182 in its
run-in (i.e. un-set) position. As manderel 20 is pulled in direction 17, pin
88a slides
relatively to mandrel 20 in direction I) so asto engage in shoulder 182.
Thereafter further
pulling of mandrel 20 in direction 17 pulls drag body 40 in direction 17 so as
to set slips
62 from slip retainer 60.
In the embodiment of Figures 1-7, as described above, once slips 62 are set,
mandrel 20 is rotated about its longitudinal axis A a one-quarter turn in
direction B, i.e.,
in the illustrated embodiment, not intending to be limiting, right or clock-
wise when
looking down mandrel 20 from its top end (end 24), so as to lock slips 62 in
the set
position (i.e., extended to grip the inner surface of casing 12).
22
CA 02854409 2014-06-16
In the embodiment of Figures 8 -10b, and as best seen in figures 9a and 9b,
pin 88 is
moved as follows in groove 180 so as to position portion 88a of pin 88 against
shoulder
184:
a) as already described, as mandrel 20 is first pulled upwardly in
direction 17, portion 88a of pin 88 slides in direction D until it engages
against shoulder 182;
b) mandrel 20 is then pulled further in direction 17 to set slips 62
outwardly of slip 60 to engage against the casing wall;
c) mandrel 20 is then given a quarter turn to the right so as to move
= portion 88a of pin 88 in direction E laterally within groove. 180, i.e.
laterally around mandrel 20 in direction E, until pin 88 abuts longitudinal
wall 186;
Is
d) continued upward tension on mandrel 20 then slides pin 88
longitudinally along longitudinal wall 186 in direction F;
e) once pin 88 reaches corner 188 in groove 180, mandrel 20 is
rotated to the left, i.e., back a quarter turn in direction G while pulling
mandrel 20 in direction 17 (i.e. in tension upwardly) so that pin 88 follows
23
CA 02854409 2014-06-16
laterally along inclined wall 190 until pin 88 is stopped against shoulder
184.
In this embodiment, when viewed in vertical elevation with the top of mandrel
20
upwards, groove 180 is in the shape of a reverse "C", although this is not
intended to be a
literal graphical description of shapes that will work, as other shapes will
work other than
exact C-shapes. Thus in this embodiment the mandrel 20 is turned, while in
tension, first
right and then left, and requires a right turn to release or unset the slips.
In embodiments
for pumps which turn the right, for example in progressive cavity pump
systems. groove
180 would be for example "C" shaped so that mandrel 20 is turned under tension
first left
then right, requiring a left turn to release the slips. This embodiment is not
illustrated as
it is a minor image of the illustrated embodiment.
Shoulder 184 forms a pocket in which portion 88a of pin 88 sits while mandrel
20
remains under tension in direction 17. Because the pocket formed by shoulder
184 is at
the bottom, that is, the lower end, of groove 180, pin 88 and thus drag body
40 cannot
move relative to mandrel 20 while mandrel 20 remains in tension in direction
17. Slips
62 thus remain locked in their set position so long as mandrel 20 remains in
tension in
direction 17. Movement of drag body 40 relative to mandrel 20 is prevented,
and
vibration of mandrel 20 cannot move pin 88 so as to unintentionally alow slips
62 to un-
set.
24
CA 02854409 2014-06-16
In the event of a break in the tubing string, etc, which allows the tubing
string to fall
down into the well (i.e., in direction 16), pin 88 slides in direction until
it is stopped
and held within pocket 192. As drag body 40 is thereby also urged in direction
16, which
would unset slips 62 where it not for the catcher function, instead, spring
194 msintains
cone 70 in its position wedged under slips 62, thereby maintaining slips 62 in
their set
position, even as conical surface 54 is slightly pulled away from under slips
62. Spring
194 thus slides slip receiver 60 and slips 62 so as to maintain conical
surface 54 on drag
body 40 firmly wedged under slips 62, along with cone 70. The slips are thus
maintained
in their set position preventing the tubing string from sliding further down
into the casing.
Until the break is repaired, pin 88 remains locked in pocket 192 in groove
180,
preventing any turning movement of mandrel 20 relative to the drag body 40.
Once the
break is repaired and the catcher function is no longer required, upward
tension may then
be re-applied to mandrel 20 in direction 17 to thereby again slide portion 88a
of pin 88
down into shoulder 184 and lock slips 62 in their continued set position.
When it is desired to unset slips 62, the process of setting the slips is
reversed, so that
portion 88a of pin 88 is returned from shoulder 184 to run-in position 186. To
accomplish this, mandrel 20 is quarter-turned right or clockwise while
lowering mandrel
CA 02854409 2014-06-16
=
20, then quarter-turned left or counter-clockwise (again from the perspective
of looking
down mandrel 20 from its upper end).
As before, if it is not possible to move pin 88 in groove 180 so as to unset
slips 62, for
example due to packing of sand or the like into groove 180, the slips 62 may
be unset by
applying a sufficient upward tension on the mandrel. In one embodiment the
shearing
tension and/or torque shears off the drive pins 88, i.e. shears off the only
pins connecting
drag body 40 to mandrel 20. In alternative embodiments, shear screws or pins
may be
provided as per in the embodiments of figures 1-7. In the embodiments of
figures 8 -10b,
cone 70 is not screwed or pinned to mandrel 20, but rather the shear screws or
pins may
mount below the drag blocks 42 on the drag body 40.
In the further embodiments of figures 11-12, shear pins 72 mount lower cone 41
to drag
body 40. Second conical surface 54 is formed on the upper end of cone 41. Cone
41
slidably mounts onto mandrel 20 so that conical surface 54 in combination with
first
conical surface 74 on cone 70 compress together along mandrel 20 to force slip
62 into
their set position as described above. As before, shear pins 72 provide a
secondary
release of slips 62 by the application of sufficient force to the drill string
so as to shear
the shear pins.
26
