Note: Descriptions are shown in the official language in which they were submitted.
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COMBINED ANTI-ROTATION AND FLOW CONTROL TOOL
FIELD OF THE INVENTION
The present invention relates to a flow control tool for connection in
series with an oil production tubing string having an inline pump to
selectively pump
fluids through either ports in the tool or a bottom end of the tubing string,
and more
particularly, the present invention relates to a flow control tool which
incorporates an
anti-rotation mechanism for anchoring the tubing string relative to a
surrounding well
casing and for simultaneously operating condition of the flow ports of the
flow control
tool.
BACKGROUND
Oil production tubing strings supported in well casings commonly use an
inline pump for producing oil from the well casing. The inline pump is
typically a
progressive cavity screw-type pump having a stator and a screw type rotor
rotatably
supported therein. The stator is connected on the tubing string with the rotor
being
connected to a series of rods extending through tubing string for driving
rotation of the
rotor in relation to the stator. The rotor is typically installed after the
stator has been
coupled to the tubing string and requires vertical placing within the tubing
string. In
this arrangement oil is typically produced by pumping the oil up through a
bottom end
of the tubing string.
A known occurrence in producing oil from a wall casing involves the well
casing and tubing string becoming plugged with sand which slows the production
of
oil. The sand can also jam the rotor within the stator of the pump which may
completely halt the production of oil. Circulation of the oil and sand within
the well
casing is then required to free the pump and clear the sand from the tubing
string.
Circulation however generally requires either pulling the tubing string from
the well
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casing which is costly and desirably avoidable or pumping fluid down through
the
tubing string. Pumping fluid down through tubing string generally involves
pulling the
rotor from the stator and pumping fluids through the same cavities which have
been
plugged with sand, The rotor must then be replaced within the stator.
If an anti-rotation tool is used with the tubing string below the inline
pump, the oil produced and the circulation fluids used must be pumped through
a
bottom of the anti-rotation tool similarly to the arrangement described above
wherein
the oil and fluids are pumped through a bottom end of the tubing string.
Canadian patent application 2,326,967 discloses a circulating apparatus
for use with an oil production tubing string in which upper and lower housing
portions
are supported for rotation relative to one another and for connection in
series with the
tubing string. Relative rotation between the upper and lower housing portions
causes
flow ports to be opened and closed. In order to operate the circulating
apparatus, a
separate anti-rotation tool is required to anchor the lower housing portion in
relation to
the upper housing portion. The ant-rotation tool therefore must be mounted
below the
circulating apparatus so that the flow ports are spaced a considerable
distance from
the open bottom end of the tubing string which corresponds to either the
bottom end
of the anti-rotation tool or any additional tubing supported therebelow.
Controlling the
condition of the flow ports can be difficult as conventional anti-rotation
tools are only
able to secure against rotation in one direction, Furthermore the condition of
the flow
ports does not correspond necessarily to the condition of the anti-rotation
tool and
accordingly the user is not necessarily aware of the condition of the fiow
ports simply
by setting or unsetting the anti-rotation tool.
US 5,623,991 to Jani discloses an anti-rotation tool for anchoring a
tubing string relative to a surrounding well casing using a series of drag
slips which
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can be displaced between set and unset positions. The device can be operable
to
anchor against rotation in either direction relative to the well casing,
however the tool
requires disassembly and reassembly before use in order to be adapted from
anchoring in one direction to the other. Accordingly when in use within a
tubing string,
the tool only operates for anchoring in one direction. No flow control ports
are
disclosed.
US application number 11/115,14 to LaClare discloses a tubing string
anchoring tool which is operable to resist rotation of a tubing string
relative to the
surrounding well casing when set in either one of two anchoring positions
corresponding to anchoring in either clockwise or counter-clockwise rotational
directions relative to the casing. No flow control ports are disclosed
however.
SUMMARY OF THE iNVENTION
According to one aspect of the invention there is provided an anti-
rotation and flow control tool for use with an oil production tubing string in
a stationary
well casing, the tool comprising:
a tubular housing extending in a longitudinal direction between an open
top end and an open bottom end, at least the top end being arranged for
threaded
connection in series with the oil production tubing string;
a flow port formed through a side wall portion of the tubular housing;
a cover member supported on the housing for movement between a
closed position in which the cover member spans the flow port and an open
position
in which the flow port is substantially unobstructed by the cover member; and
an anti-rotation mechanism supported on the housing for movement
between an unset position and a set position in which an overall diameter of
the tool is
greater than in the unset position for anchoring the tubular housing against
rotation in
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one direction relative to the stationary well casing;
the cover member and the anti-rotation mechanism being coupled for
movement together such that the cover member is in the open position when the
anti-
rotation mechanism is in the set position.
By providing an anti-rotation mechanism and a member which controls
opening and closing of flow ports operable together within a common tool, the
condition of the flow ports is always known and readily controlled as the
condition of
the flow ports can be made dependent upon the condition of the anti-rotation
mechanism when the two are moveable together. By providing flow ports and an
anti-
rotation mechanism commonly on a single housing, the flow ports can also be
provided as close as possible to the bottom of the tubing string as no
additional
tooling or tubing is required below the tool when both an anti-rotation
mechanism and
flow ports are provided commonly thereon.
Preferably the flow ports are fully open when the anti-rotation
mechanism is set against righthand rotation of the tubing string in relation
to the
stationary well casing.
The anti-rotation mechanism may anchor the tubing string in two
directions. In this instanee the anti-rotation mechanism is operable from the
unset
position in a first direction into a first set position anchored against
righthand rotation
of the tubing string relative to the well casing and in a second direction
into a second
set position in which the tubing string is anchored against lefthand rotation
in relation
to the stationary well casing.
There may be provided a stop member selectively supported on the
housing which is arranged to restrict movement of the anti-rotation mechanism
in one
of the first or second directions from the unset position.
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The flow port may be nearer to the top end of the tubular housing than
the bottom end.
When there is provided a rigid tag bar spanning diametrically across the
tubular housing, the bar is preferably positior-ed adjacent the bottom end of
the
5 tubular housing substantially below the anti-rotation mechanism and below
the flow
port.
When there is provided a plurality of flow ports through the side wall
portion of the tubular housing, they are preferably located at
cirCumferentiaily spaced
positions. When there are provided two flow ports, they are preferably located
at
diametrically opposed positions in the side wall portion of the tubular
housing.
The cover member which operates the flow ports preferably oomprises a
collar rotatably supported about the tubular housing and including a
corresponding
port therein for selective alignment with the flow port in the tubular
housing.
Preferably both the top and bottom ends of the tubular housing are
threaded for connection in series with tubing of the tubing string, in which
the top and
bottom ends of the tubular housing are fixed in relation to one another.
The anti-rotation mechanism comprises a fixed jaw projecting radially
from the tubular housing in fixed relation therewith and a floating jaw
projecting
radially from the housing for rotation about a central axis of the tubular
housing.
The floating jaw portion of the anti-rotation mechanism may be
supported on the same collar rotatable about the housing which operates the
flow
ports.
There may be provided a circumferential slot in one of the collar or the
housing and a stop mounted on the other of the collar or the housing in which
the stop
member is slidable along the slot as the fixed jaw is displaced relative to
the floating
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jaw.
The flow port may be in the open position when the fixed jaw is rotated
from the unset position more than 90 in a righthand direction relative to the
floating
jaw. Preferably the flow port is fully open when the jaws are rotated near 110
degrees relative to one another.
The floating jaw preferably projects radially outwardly from a central axis
of the tubular housing greater than the fixed jaw for gripping the well casing
before the
fixed jaw.
There may be provided a plurality of projections extending from the
bottom end of the housing in the longitudinal direction of the housing at
circumferentially spaced positions about the housing.
One embodiment of the invention will now be described in conjunction
with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic elevational view of a tubing string within a
stationary well casing.
Figure 2 is an enlarged elevation view of the tool for connection in series
with the tubing string according to a first embodiment.
Figure 3 is a sectional view along the line 3-3 of Figure 2.
Figure 4 is a sectional view along the line 4-4 of Figure 2 in an unset
position of the tool.
Figure 5 is a sectional view along the line 4-4 of Figure 2 in which the
tool is partially rotated towards one of the set positions.
Figure 6 is a sectional view along the line 4-4 of Figure 2 in which the
tool is shown in one of the set positions.
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Figure 7 is an elevational view of a second embodiment of the tool.
Figure 8 is a sectional view along the line 8-8 of Figure 7 showing the
tool in an unset position.
Figure 9 is a sectional view along the line 8-8 of Figure 7 showing the
tool in a set position against further right hand rotation of the tubing
string.
In the drawings like characters of reference indicate corresponding parts
in the different figures.
DETAILED DESCRIPTION
Referring to the accompanying figures there is illustrated an anti-rotation
and flow control tool generally indicated by reference numeral 10. Two
embodiments
of the present invention are shown in the accompanying figures and accordingly
some
of the features common to both embodiments will first be described herein.
The tool 10 is intended for use in anchoring and controlling circulation of
fluids in a tubing string 12 supported within a well casing 14. The tool is
typically used
with a conventional tubing string 12 having an inline pump 16 and which is
arranged
to be suspended within the stationary well casing 14 by a dognut 20 located
adjacent
the welihead.
The pump 16 is an inline progressive cavity pump having a stator 22
arranged to be coupled in series with the tubing string and a screw type rotor
24
rotatably supported therein. Rotation of the rotor 24 is driven by a series of
rods 26
extending through the tubing string 12.
The tool 10 mounts directly below the pump 16 and operates to
selectively control flow through ports in the tool or through the bottom end
thereof
comprising the bottom end of the string. In addition the tool operates to
prevent
righthand or clockwise rotation, as viewed from above, of the tubing string
relative to
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the surrounding stationary well casing when set. Without any modification of
the tool
being required, the tool can also be unset and subsequently set into a second
set
condition in which the tool is instead anchored to the well casing so as to
prevent
further lefthand or counter-clockwise rotation to the tubing string relative
to the well
casing as viewed from above.
The tool 10 includes a tubular housing 28 which is elongate in a
longitudinal direction between an open top end 30 and an open bottom end 32.
At the
top end, the housing 28 is threaded for connection threadably in series with
the tubing
string directly below the pump. At the opposing bottom end 32 the housing can
also
be threaded for threaded connection of additional tubing sections if desired.
A hollow
interior of the housing 28 has a substantially constant interior diameter
between the
open top and bottom ends.
Turning now to the first embodiment, an upper portion 34 of the outer
surface of the housing however has a larger outer diameter than a remaining
main
portion 36 of the housing. Accordingly a downwardly facing shoulder 38 is
defined at
the intersection of the upper portion 34 and the main portion 36. The shoulder
comprises an annular surface about the housing which is generally
perpendicular to
the longitudinal direction. Below the shoulder 38, the main portion 38 has a
substantially constant outer diameter which is less than the outer diameter of
the
upper portion 34.
The top end of the housing is intemally threaded and the bottom end of
the housing is externally threaded according to the first embodiment.
A first collar 40 is supported on the outer surface of the main portion 36
of the housing for abutment against the shoulder 38. The collar is slidably
mounted
onto the main portion 36 from the bottom end of the housing and includes an
interior
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diameter which is near to the dimension of the outer diameter of the main
portion 36
of the housing. Once abutted against the shoulder 38 the first collar 40
remains freely
rotatable about a central axis of the housing extending in the longitudinal
direction, in
relation to the housing.
A second collar 42 is also mounted on the main portion 36 of the
housing by slidably mounting onto the housing over the bottom end thereof. The
second collar has similar dimensions to the first collar so that the first and
second
collars together when abutted adjacent one another in the longitudinal
direction
substantially span the length of the main portion 36. The second collar 42 is
fixed onto
the main portion of the housing by suitable fasteners or welding so that the
second
collar 42 is secured against rotation and sliding movement in the longitudinal
direction
in relation to the housing. The first collar 40 is thus abutted between the
shoulder 38
of the upper portion 34 of the housing and the second collar 42 therebelow
which is
also fixed in relation to the housing 28. Though fixed and prevented from
sliding
movement in the longitudinal direction, the first collar 40 remains rotatable
about the
central axis of the housing.
Also, in the first illustrated embodiment a tag bar 44 is mounted to
extend through the main portion 36 of the housing and the second collar 42 to
assist
in fixing the second collar in relation to the housing. The tag bar 44
comprises a fixed
and rigid bar which extends diametrically across the housing 28 adjacent the
bottom
end of the second collar 42. An enlarged head 46 at one end of the bar is
received in
a corresponding recess in the outer surface of the housing at one side thereof
while a
fastener secures a second portion of enlarged diameter 48 in a corresponding
recess
at a diametrically opposed position in the side wall of the housing once the
tag bar is
inserted through corresponding apertures in the housing and the second collar
42,
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The tool further includes an anti-rotation mechanism 50 in the form of a
floating jaw 52 supported on the first collar 40 and a fixed jaw 54 supported
on the
second collar 42, The floating jaw 52 extends in the longitudinal direction
substantially
the full length of the first collar and projects outwardly from the collar in
a radial
5 direction from one side thereof. A free end 56 of the floating jaw 52 lies
generally
parallel to the longitudinal direction of the housing and includes teeth 58
formed
therein extending the length of the jaw with aggressive biting edges for
griping the
surrounding well casing. The floating jaw 52 is rotatable with the first
collar fully about
the housing 28.
10 The fixed jaw 54 supported on the second collar also extends in a
longitudinal direction of the housing substantially the full length of the
second collar.
The fixed jaw 54 also extends radially outwardly to a free end 60 which lies
generally
parallel to the longitudinal direction. The fixed jaw 54 is fixed in
orientation relative to
the second collar which is in turn fixed to the housing so that the fixed jaw
remains
fixed in position in orientation relative to the tubular housing 28 of the
tool, The free
end 60 includes carbide inserts which are arranged to grip the surrounding
well casing
along the length of the fixed jaw, however the teeth 58 on the floating jaw
project
radially outwardly from the central axis of the tubular housing a distance
which is
slightly greater than the free end of the fixed jaw 54 so that the floating
jaw will tend to
grip the surrounding well casing before the fixed jaw.
As shown in Figure 4, the anti-rotation mechanism is in an unset
position when the fixed jaw 54 and the floating jaw 52 are generally aligned
with one
another. In this position the overall diameter of the tubing is substantially
less than the
interior diameter of the well casing so that the tubing string remains
rotatable within
the well casing. Due to the floating jaw having teeth which project radially
and
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outwardly beyond the free end of the fixed jaw, when the tubing string is
rotated in a
clockwise or righthand direction as viewed from above as shown in Figure 5,
the
floating jaw will tend to grip the well casing and remain relatively fixed in
orientation
relative to the well casing while the fixed jaw 54 rotates away from the
floating jaw to
increase the overall diameter of the tool.
Once the jaws are near approximately 110* of separation relative to the
central axis of the tubular housing. the overall diameter of the tool is
sufficiently
increased that the tool is wedged within the internal diameter of the well
casing so that
further clockwise or righthand rotation of the tubing string within the well
casing is
prevented by the anti-rotation mechanism 50. Rotation of the tubing string in
the
opposite direction or the lefthand or counter-clockwise direction will cause
the fixed
jaw to again return closer to the floating jaw to reduce the overall diameter
of the tool
and permit the tubing string to again be rotatable within the well casing.
Rotation of
the fixed jaw in the counter-clockwise or lefthand direction, as viewed from
above,
past the floating jaw will cause the overall diameter of the tool again to
increase for
subsequently reaching a second set position in which the jaws and the tubular
housing are again wedged within the well casing to prevent further rotation in
the
lefthand or counter-clockwise direction.
The tubular housing also includes flow ports 62 extending through the
side wall portion of the housing at two diametriGally opposed positions so
that the
ports 62 are circumferentially spaced from one another. Each port 62 is
elongate in
the longitudinal direction and spans approximately the mounting location of
the first
collar between the upper portion 34 of the housing and the second collar 42
fixed
thereon.
Two corresponding ports 64 are also located in the first collar 40 at two
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diametrically opposed positions therein. The corresponding ports 64 are also
elongate
in the longitudinal direction and are of the same size, shape and orientation
as the
flow ports 62 for alignment therewith. When rotating the first collar 40 the
remaining
wall portion of the collar acts as a cover member to selectively enclose and
cover the
flow ports 62 through a portion of rotation of the first collar. Alternatively
when the
corresponding ports 64 align with the flow port 62 the ports are fully opened
for
pem}itting fluid flows therethrough. The first collar 40 is thus rotatable
between an
open position in which the corresponding ports 64 are aligned with the flow
ports 62
so that the flow ports are substantially unobstructed by the covering wall
portion of the
first collar and a closed position in which the wall portion of the first
collar fully spans
the flow ports and prevents fluid flow therethrough.
The floating jaw of the anti-rotation mechanism 50 is fixed in relation to
the first collar 40 and the corresponding ports 64 thereon with the jaw being
oriented
in relation to the ports such that the flow ports 62 are in the open position
when the
anti-rotation mechanism is in the set position against further righthand
rotation as
shown in Figure 6, while the ports are in the closed position when the anti-
rotation
mechanism is in the unset position with the jaws 52 and 54 aligned with one
another.
In the unset position of Figure 4, the ports 64 of the first collar are offset
circumferentially by 90 in relation to the flow parts 62 in the housing. The
dimensions
of the ports are arranged so that the tubing string must be rotated clockwise
in relation
to the first collar supporting the floating jaw thereon by more than 90 , and
in the order
of approximately 110 to fully open the ports into the set position against
righthand or
clockwise rotation as viewed from above. As shown in Figure 5, the ports begin
to
open through approximately 60 of clockwise rotation of the tubing string
relative to
the floating jaw.
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13
As noted above, the tool according to the first embodiment is assembled
by first sliding the first collar onto the main portion of the housing over
the bottom end
of the housing, and then subsequently sliding the second collar onto the main
portion
of the housing again over the bottom end of the housing. The second collar is
then
fixed in place with the tag bar.
The tag bar location adjacent the bottom end of the second collar
ensures that the tag bar is positioned below the flow ports and substantially
below the
anti-rotation mechanism. As the flow ports are operated between open and
closed
positions and as the anti-rotation mechanism is operated between set and unset
positions, the threaded ends of the housing remain fixed relative to one
another for
connection in series with the tubing string.
Turning now to the embodiment of Figures 7 through 9, the fixed jaw 54
in this instance is supported on a collar 42 which instead is integrally
formed with the
housing 28 of the tool 10. The top end of the housing 28 in this instance is
externally
threaded and has an overall diameter which is near to the overall diameter of
the main
portion of the housing onto which the first collar 40 is slidably mounted for
supporting
the floating jaw 52 thereon. The second collar 42 in this instance comprises a
portion
of the housing which is enlarged in diameter to define a shoulder in the form
of an
annular end face 80 lying perpendicular to the longitudinal direction of the
housing
against which a bottom end of the first collar 40 is abutted.
An annular grove 82 is formed in the housing at the top end of the first
collar 40 for receiving a split snap ring 84 therein to abut against the top
end of the
first collar 40 so that the first collar remains rotatable about the main
portion of the
housing while being fixed in the longitudinal direction in abutment between
the snap
ring 84 and the end face 80 of the second collar 42 integrally forming an
enlarged
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14
diameter portion of the housing below the first collar 40. In further
embodiments the
second collar 42 may comprise a collar slidably mounted onto the housing which
is
instead fixed in relation to the housing by bolting or welding.
The first collar 40 can also be held in place longitudinally by a pair of
stop members 86 received within respective circumferentially oriented slots 88
formed
in the first collar, Two slots 88 are provided in the first collar 40 at
opposing ends
thereof to extend circumferentially only partway about the housing in the
order of 110
degrees for example. In this instance, the ports 62 and 64 in the housing 28
and in
the collar 40 respectively, along with the floating jaw 52 on the first collar
40 and the
fixed jaw 54 on the housing, are arranged similarly relative to one another as
in the
previous embodiment. The stops 86 are mounted within the respective slots 88
for
sliding movement along the slots when the housing is rotated relative to the
first collar
40 as the stops 86 are fixed on the housing 28 for rotation therewith. The
stops 86
comprise lugs which are threadably mounted within cooperating threaded bores
in the
housing so that the stops can be selectively separated or removed as desired
for
permitting free rotation of the first collar 40 about the housing or when
removing the
collar from the housing.
When the stops 86 are mounted on the housing, the slot orientation in
relation to the stops is arranged so that the stops abut one end of the slots
88 in the
unset position of the tool as shown in Figure 8, while also being arranged for
the stops
to engage the opposing end of the respective slots 88 in the set position as
shown in
Figure 9 in which the tool is set against further right-hand rotation of the
tubing string
relative to the floating collar 40 supporting the floating jaw 52 thereon. By
arranging
the stops to abut one end of the slots 88 in the unset position of Figure 8,
further
rotation of the housing in a left-hand direction relative to the floating jaw
on the collar
CA 02555023 2006-08-03
40 is prevented so that the tool cannot be set in the second direction into
the second
set position unless the stop members 86 are removed from the housing, Once the
stops are removed, the first collar 40 is freely rotatable in either direction
from the
unset position to either one of two set positions as in the previous
embodiment.
5 The embodiment of Figure 7 also differs from the previous embodiment
in that the first collar 40 and the corresponding ports 62 and 64 in the
housing and
collar respectively span much longer in the longitudinal direction in relation
to the
floating jaw 52 and the fixed jaw 54. Accordingly the ports in the second
embodiment
are in the order of twelve inches long while the floating collar 40 is near
fourteen
10 inches long in the longitudinal direction as compared to ports which are
five inches
long within a collar which is seven and a half inches long as shown in the
previous
embodiment. The ports are thus approximately twice the length of the jaws in
the
longitudinal direction and are arranged to span between the two slots 88 at
opposing
ends of the first collar 40.
15 At the bottom end of the housing 28, a tag bar 44 is provided
diametrically across the housing similar to the previous embodiment, however
the
open bottom end of the housing is configured differently as compared to the
previous
embodiment. A plurality of projections 90 are provided at the bottom end which
extend
outward from the housing in the longitudinal direction beyond the bottom end
at a
plurality of evenly spaced circumferential positions about the housirrg. The
projections
90 result in a varied contact area between the interior of the tubular housing
and the
surrounding well.
When installing the tool at the bottom of the tubing string, the flow ports
are accordingly close to the open boitom end of the tubing string which
corresponds
to the open bottom end of the too1. Upon assembly of the tubing string, the
rotor 24 of
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the pump is inserted into the tubing string until the bottom end of the rotor
is engaged
with the tag bar for locating the pump within the tubing string. Once the
rotor has been
engaged on the tag bar it may be raised into the stator by a predetermined
vertical
spacing to ensure the rotor is properly located. In order to produce oil from
the well,
the tubing string is rotated in a direction corresponding to righthand
rotation until the
anti-rotation mechanism of the tool 10 is set in an engaged position with the
well
casing for restricting further righthand rotation of the tubing string
relative to the
casing. The flow ports in this instance are automatically opened by the
setting action
of the anti-rotation mechanism for producing from two separate locations in
the well
corresponding to the flow ports and the open bottom end of the tubing string.
In the event that the tubing string and well casing become pulled with
sand and circulation is required, the tubing string can be rotated in a
direction
corresponding to lefthand rotation as viewed from above so as to automatically
both
unset the tool 10 and close the ports to flush fluids down through the bottom
end of
the tubing string. Aitematively, the tool can remain in the set position of
Figure 6 or
Figure 9 with the flow ports open for flushing fluids through both the flow
ports and
through the bottom end of the housing. Pulling the rods and the rotor upwardly
from
the inline pump permits the circulating fluids to be pump down through the
tubing
string and through the tool 10 to the bottom end thereof for clearing the
sand.
Once the sand has been sufficiently cleared from the tubing string, the
string may once again be prepared for production by inserting the rotor 24
back into
the stator 22, once again using the tag bar as a reference. Rotating the
tubing string
in a direction corresponding to righthand rotation will set the tool in an
engaged
position with the well casing and the flow ports will automatically be opened
as shown
in Figures 6 and 9. Setting the anti-rotation mechanism by rotating the tubing
string in
CA 02555023 2006-08-03
17
a lefthand direction as viewed from above will also ensure that the ports are
closed if
desired for a flushing operation. By locating both the corresponding ports
that control
opening and closing of the flow ports and the floating jaw of the anti-
rotation
mechanism on a common collar on the housing, the flow ports are always ensured
to
be in an open position when the anti-rotation mechanism is in a set position.
Since various modifications can be made in my invention as herein
above described, and many apparently widely different embodiments of same made
within the spiri# and scope of the claims without department from such spirit
and
scope, it is intended that all matter contained in the accompanying
specification shall
be interpreted as illustrative only and not in a limiting sense.
