Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND TOOL FOR PERFORATING A WELLBORE CASING IN A
FORMATION USING A SAND JET, AND USING SUCH TOOL TO FURTHER
FRAC THE FORMATION
FIELD OF THE INVENTION
The present invention relates to a downhole tool for insertion in a wellbore
for
perforating a casing in such wellbore and further fracking an underground
hydrocarbon
formation in which such wellbore is located. More specifically, the present
invention relates
to a tool which has capability to perform perforating, cleaning, and fracking
without having
to trip the tool out. Various methods for performing operations are further
disclosed.
BACKGROUND OF THE INVENTION AND DESCRIPTION OF THE PRIOR ART
The below provided background information and description of prior
publications is
provided for the purpose of making known information believed by the applicant
to be of
possible relevance to the present invention. No admission is necessarily
intended, nor should
be construed, that any of the below publications and information provided
constitutes prior
art against the present invention.
In order to prepare a cased wellbore drilled in a hydrocarbon formation for
production, such cased wellbore first needs to be perforated along portions of
its length in
order for hydrocarbons to flow into such wellbore for pumping to surface.
Prior art apparati and methods for creating perforations in the wellbore
casing have
typically comprised placing a string of explosive charges , namely shaped
charges adapted to
explode radially outwardly, within and along a length of the wellbore, and
igniting such
charges and thereafter withdrawing the perforating string from the wellbore.
Other methods and apparati for creating perforations along a wellbore have
involved
insertion of a tool having one or more nozzles, adapted direct radially
outwardly therefrom an
abrasive fluid under high pressure. Such abrasive high pressure fluid impacts
the wellbore
casing and due to its abrasive nature, cuts a hole or holes in the wellbore
casing. Such tool is
moved along the wellbore casing to create additional perforations in such
wellbore along a
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desired length thereof.
Typically, after a wellbore has been perforated, as a means to increase the
rate and
volume of production from the formation prior to commencing production
therefrom a
fracking fluid, typically containing proppants, acids, diluents, and/or other
flow-stimulating
additives, is injected under high pressure into the wellbore in a fracking
operation. Typically
only portions of a wellbore are "fracked" at a time, requiring a zone of a
wellbore that is to be
fracked to be isolated from other regions of the wellbore, typically by
rubberized packer
elements which are actuated by hydraulic pressure.
In such fracking operation, when a particular one or number of perforations
along a
wellbore are isolated by packers, a high pressure fluid is flowed into the
wellbore and thus
into the formation in the region of the perforation(s). Such high pressure
fluid creates fissures
within the formation. The created fissures (typically lines of fracture within
the formation)
generally emanate radially outwardly from the wellbore and thereby create flow
channels in
the formation which lead to the wellbore, thereby assisting hydrocarbons to
subsequently
flow into and be collected by the wellbore.
Unsatisfactorily however, no tool exists that is able to both perforate using
abrasive
jets, as well as carry out fracking operations without having to use separate
tools and trip the
tool out, in an effective and efficient manner.
U.S. Pat. No. 4,781,250 to McCormick et al., entitled "Pressure Actuated
Cleaning
Tool" teaches a downhole tool for cleaning tubing, casing and flow lines with
pressurized
cleaning fluid pumped through coiled tubing. The cleaning tool is rotated by a
"J"-slot
indexing tool , which activated by fluid pressure changes and a spring, to
effectively rotate the
tool 360 . McCormick et al does not, however, disclose any apparati or method
on the same
tool for further being able to carrying out fracking of the formation via the
perforations
created by such same tool.
U.S. Pat. No. 7,963,332 to Dotson, entitled "Apparatus and Method for Abrasive
Jet
Perforating", teaches a device using an abrasive jet for perforating, with a
mechanical locating
collar. Such patent however does not teach any sliding sleeve to open and
close the
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perforating jet, nor does it teach use of such perforator jet, in combination
with a packers, a
bypass, a "j" slot used to set and release a setting tool, and frac ports, all
incorporated into
and for use by the same tool to permit both perforating and fracking using the
same tool.
Likewise, and to similar effect, U.S. Pat. No. 8,757,262 similarly to Dotson,
entitled
"Apparatus and Method for Abrasive Jet Perforating and Cutting of Tubular
Members",
teaches an abrasive jet perforating tool, coupled rotatably to a tubing
string, and a horizontal
indexing tool coupled thereto. An extension tool with a protective sleeve is
used to protect the
apparatus. Again, however, such patent fails to disclose any apparati or
method on the same
tool for further being able to carrying out fracking of the formation via the
perforations
created by such same tool.
U.S. Patent No. 5,765,756 by Jordan et al., entitled "Abrasive Slurry Jetting
Tool and
Method" teaches an abrasive jet perforating tool with telescoping jet nozzles.
The jetting
nozzles are operated perpendicularly to the longitudinal axis of the tool
body, although the
nozzle assemblies can pivot back into the tool body for retrieval back up the
wellbore.
Jordan et al similarly fails to disclose a single tool with further components
which allow not
only perforation but also setting of the tool to frac as well as perforate, or
a method by which
fracking and perforation using an abrasive jet may be accomplished by a single
tool.
Accordingly, a clear need exists in the wellbore completion industry for a
tool which
uses abrasive jetting to create perforations in wellbore casings, and which
may further
accomplish fracking of the formation using the same tool, to thereby save time
and speed
completion of wellbores in preparation for hydrocarbon production therefrom.
SUMMARY OF THE INVENTION
In a broad aspect of the present invention, the present invention provides a
downhole
tool which may not only use abrasive jet, such as a fluid containing and
having dispersed
therein an abrasive material(s) such as sand or silica granules for creating
perforations in a
wellbore casing, but which may further, during the creation of perforations in
the wellbore
casing, frack the formation by injection of frack fluid into the formation via
the perforations
created in the casing.
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Advantageously, the tool of the present invention is further able to flush the
wellbore
when carrying out such perforation and fracking operation, so as to thereby
clear the wellbore
of detritus created as a result of the creating of perforations within the
wellbore casing.
Accordingly, in broad aspect of the present invention, the invention relates
to a
downhole tool for creating perforations in a wellbore casing and further
injecting a fluid in
the created perforations using such tool, comprising:
an elongate substantially cylindrical member, having a hollow bore and an
outer
periphery, adapted for insertion in a wellbore, comprising:
(i) an uphole cylindrical, hollow slidable sleeve within the bore;
(ii) a jet port, situated in said outer periphery, configured to direct a
stream of
pressurized abrasive fluid radially outwardly from the tool, fluid
communication of said jet
port with the bore allowed and prevented by slidable movement of the slidable
sleeve;
(iii) an uphole packer member, situated on a portion of the periphery downhole
of the
jet port;
(iv) an expandable chamber and associated piston member, said chamber adapted
to
receive fluid under pressure from the bore and cause said associated piston
member, when
pressurized fluid is supplied to the bore, to compress and outwardly expand
the uphole packer
member;
(v) a downhole packer member, situated on a portion of the periphery downhole
of
said uphole packer member;
(vi) a frac port in said periphery of the cylindrical member, intermediate the
uphole
and downhole packer members;
(vii) a slidably moveable guide member, situated on said cylindrical member
having
radially protruding slip members thereon configured to frictionally engage
said wellbore
casing when the tool is inserted therein, said guide member situated on said
tool downhole of
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the downhole packer member, said guide member further having radially
expandable jaw
members on an uphole side thereof; and
(viii) a T slot subassembly within said tool situated downhole of the downhole
packer member, coupled to an associated cylindrical hollow mandrel;
wherein said T slot subassembly, when downward force is applied to said tool
and
said guide member frictionally engages said wellbore casing , said T slot
subassembly does
not allow further relative downward movement of a lower portion of said
downhole packer
member relative to said guide member and thus does not allow said jaw members
to become
actuated; and
wherein said T slot sub-assembly, when an upward pulling force is applied to
said
tool and thereafter a downward force is re-applied to said tool, is then in a
'set' position
where:
(i) said lower portion of said downhole packer member is allowed further
downward downhole movement to allow said lower portion of said downhole packer
member
to be forced against said jaw members so as to expand them radially outwardly
to engage said
wellbore casing.
In a further preferred embodiment, to assist in moving the tool uphole after
having created a perforation in the wellb ore casing, a bypass port in said
periphery of the
cylindrical member uphole of the downhole packer, is provided. Such bypass
port when open
provides fluid communication between an exterior of the tool and the interior
bore and permit
fluid exterior to the tool and above said downhole packer to flow into said
bore and bypass
the downhole packer. A slidable valve member slidably opens and closes the
bypass port.
When an upward force is exerted on the tool, the slidable valve member is in
an open
position. When the T slot is subsequently operated to the 'set' position by
subsequent
downward force on the tool and/or a fluid pressure is applied to the bore of
the tool, the
slidable valve is moved to a closed position thereby closing the bypass port.
In either of the above embodiments, the slidable sleeve is adapted to be moved
so as
to uncover the when either:
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(i) the guide member remains at a specific location within said wellbore
casing and
said remainder of said tool is raised uphole;
(ii) when a pick-up tool is inserted within the wellb ore and within the tool,
to slidably
reposition the slidable sleeve; or
(iii) when hydraulic fluid pressure applied to the bore of the tool causes the
slidable
sleeve to then move to a position where the jet port is then open.
In a further preferred embodiment, the bore of the tool, in the region of the
frac port,
is provided with a deflector, typically a conical deflector, to deflect
fracking fluid from
within the bore of the tool out the frac port.
In a further preferred embodiment, an annular cup seal is provided on the
periphery
of the tool intermediate the jet port and the downhole packer member, which
reduces flow of
abrasive pressurized fluid and associated wellbore.casing cuttings downhole.
In a further broad aspect of the present invention, such invention comprises a
method
for creating perforations in a wellbore casing using jet abrasion and
fracturing a hydrocarbon
formation by injecting a pressurized fracking fluid into said formation via
the created
perforation without having to trip a jet abrasion tool out of said wellbore.
Such method at
least in part comprising the steps of:
(i) running the tool, which possesses a hollow bore in the region of a jet
port and a
frac port thereon, into the wellbore casing to a desired depth within the
wellbore casing;
(ii) causing a slidable sleeve covering the jet port to move so as to allow
fluid
communication between the bore of said tool and the jet port;
(iii) injecting an abrasive pressurized fluid within the wellbore and within
the bore and
causing the jet port to expel the abrasive fluid in a radially outward manner
to thereby create
a perforation in the wellbore casing at said desired depth;
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(iv) ceasing injection of the abrasive pressurized fluid, and causing the
slidable sleeve
to then cover and thereby close the jet port;
(v) pulling upwardly on the tool to position the created perforation along the
wellbore casing between an uphole and downhole packer member situated on such
tool;
(vi) pushing slightly down on an upper portion of the tool to thereby push the
slidable
sleeve back over the jet port so as to close the jet port and to further cause
jaw members on
such tool to be forced against the wellbore casing so as to thereby secure the
tool within the
wellbore casing and to cause the downhole packer member to become compressed
and to
expand radially outwardly;
(vii) injecting a pressurized fracking fluid into the wellbore casing and into
the bore,
and causing a piston member in the tool to compress the uphole packer member
and
cause the uphole packer member to expand same radially outwardly, and causing
the
pressurized fluid to pass into the created perforation via the frac port;
(viii) ceasing supply of the pressurized fracking fluid; and
(ix) pulling upwardly on the tool to disengage the jaw members and re-position
the
tool further uphole for creating further perforations and injecting further
frac fluid into further
created perforations.
In a further refinement of the above method, step (v) further comprises the
step, when
pushing downwardly on a portion of the tool uphole of the downhole packer, of
closing a
bypass port to thereby prevent the otherwise bypass of the fracking fluid
downhole.
In a further refinement of the above method, step (ii) further comprises the
step of
pulling an uphole portion of the tool uphole to thereby move said slidable
sleeve upward so
as to uncover said jet port .
In an alternative embodiment, step (ii) further comprises the step of
inserting a pick up
tool within the wellbore casing and the bore of said tool to move said
slidable sleeve uphole
to a position uncovering said jet port.
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In all of the foregoing embodiments, the pressurized abrasive fluid and said
pressurized fracking fluid may be one and the same fluid.
In a further preferred embodiment of the above method, such method includes a
cleaning or flushing step, to flush detritus in the wellbore resulting from
the abrasive
perforation step. In such further preferred embodiment, the method further
comprises a step,
after step (iii) but prior to the injection of pressurized fracking fluid in
step (vii), of injecting a
flushing fluid to flush the tool and/or the annular region between the
wellbore casing and the
tool with said flushing fluid to thereby flush abrasive fluids and/or wellbore
casing of such
detritus. The flushing/cleaning fluid may be circulated in the region of the
tool by applying a
high pressure cleaning fluid to the bore of the tool, and causing the jet port
and/or frac port to
expel such fluid into the annular region between the tool and the wellbore,
where either or
both of the uphole and downhole packer members prevent the flow of such
cleaning fluid
downhole, and which flushing/cleaning fluid is then flowed uphole and
recovered from
surface, thereby cleaning and flushing the entirely of the wellbore uphole of
the tool, and in
the region of the tool uphole from one or both of the uphole and downhole
packer members
Lastly, in a further refinement of the invention to further decrease the time
to both
perforate and frac, the abrasive pressurized fluid and the pressurized
fracking fluid are one
and the same fluid. In such embodiment, simultaneously with step (vii), by
injection of such
abrasive/fracking fluid to frac the formation, the slidable sleeve is caused
to move to an open
position and expelling said abrasive/fracking fluid in a radially outward
manner via said jet
port to thereby create a further perforation in said wellbore, and
step (ix) further comprises the step of repositioning the tool further uphole
so as to
further position said upper packer member on said tool above said further
perforation, and
again supplying the abrasive/fracking fluid to the tool when in said further
position to
additionally frac the formation is the region of the further perforation in
the wellbore.
In such embodiment/refinement, due to carrying out a perforation and a
fracking
operations at the same time, the time to both perforate a wellbore and frac
the formation can
accordingly advantageously be further reduced.
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BRIEF DESCRIPTION OF THE DRAWINGS
Further advantages and permutations and combinations of the invention will now
appear from the above and from thP following detailed description of the
various particular
embodiments of the invention, taken together with the accompanying drawings
each of which
are intended to be non-limiting, in which:
FIG. 1 is a perspective view of the downhole tool of the present invention,
broken
into three individual segments for illustrative purposes only;
FIG. 2A is a partial cross-sectional view of a first embodiment of the
downhole
tool, showing the upper portion of the tool, with the uphole portion of the
tool being
positioned on the left-hand side of Fig. 2A, when the tool is being "run" into
the wellbore;
FIG. 2B is a partial cross-sectional view showing the lower portion of the
tool of
Fig. 2A, with the downhole portion of the tool being positioned on the right
hand side of Fig.
2B and when the tool is being "run" into the wellbore, further showing in
relief a view on the
exterior of the tool in the region of slot, showing the position of such
'j'-slot sub-assembly
when the tool is in the "running" position;
FIG. 3A is a partial cross-sectional view of the same first embodiment of the
downhole tool, again showing the upper portion of the tool, with the uphole
portion of the tool
being positioned on the left-hand side of Fig. 3A, but instead when the tool
is in the "pulling"
position wherein a portion of the tool having been pulled uphole for effecting
operation of the
`j' slot;
FIG. 3B is a partial cross-sectional view of the same first embodiment of the
downhole tool shown in Fig. 3A, showing the lower portion of the tool, again
showing the
downhole portion of the tool being positioned on the right-hand side of Fig.
3B, when the
tool is configured in the "pulling" position, further showing in relief a view
on the exterior of
the tool in the region of
slot sub-assembly, showing the position of such 'j'-slot sub-
assembly when the tool is in the "pulling" position;
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FIG. 4A is a partial cross-sectional view of the same first embodiment of the
downhole tool, again showing the upper portion of the tool, with the uphole
portion of the
tool being positioned on the left-hand side of Fig. 4A, but instead when the
tool is in the
"set" position after a downhole force has subsequently been applied to the
tool from the
"pulling" position shown in Fig.'s 3A & Fig. 3B;
FIG. 4B is a partial cross-sectional view of the same first embodiment of the
downhole tool shown in Fig. 4A, showing the lower portion of the tool, again
showing the
downhole portion of the tool being positioned on the right-hand side of Fig.
4B, when the
tool is configured in the "set" position, further showing in relief a view on
the exterior of the
tool in the region of 'j' slot sub-assembly, showing the position of such 'j'-
slot sub-assembly
when the tool is in the "set" position;
Fig. 5 is a flow diagram of a particular method of the present invention for
perforating a wellbore casing and fracking the formation via the created
perforations;
FIG. 6A is a partial cross-sectional view of a second embodiment of the
downhole
tool, showing the upper portion of the tool (the lower portion of the tool
remaining the same
as in Fig. 2B), with the uphole portion of the tool being positioned on the
left-hand side of
Fig. 6A, when the tool is being "run" into the wellbore;
FIG 7A is a partial cross-sectional view of the same second embodiment of the
downhole tool, again showing the upper portion of the tool (the lower portion
of the tool
remaining the same as in Fig. 3B), with the uphole portion of the tool being
positioned on the
left-hand side of Fig. 7A, but instead when the tool is in the "pulling"
position wherein a
portion of the tool having been pulled uphole for effecting operation of the T
slot; and
FIG. 8A is a partial cross-sectional view of the same first embodiment of the
downhole tool,
again showing the upper portion of the tool (the lower portion of the tool
remaining the same
as in Fig. 4B), with the uphole portion of the tool being positioned on the
left-hand side of
Fig. 8A, but instead when the tool is in the "set" position after a downhole
force has
subsequently been applied to the tool from the "pulling" position shown in
Fig.'s 7A.
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DETAILED DESCRIPTION OF SOME PREFERRED EMBODIMENTS
In the following description, similar components in the drawings figures are
identified with corresponding same reference numerals.
Fig. 1 and Fig.' s 2A, 2B, 3A, 3B, 4A, 4B together illustrate one embodiment
of
the downhole tool 10 of the present invention, with Fig. 1 depicting the tool
10 separated
into three individual segments for illustrative purposes only, with remaining
Fig's 2A, 3A,
and 4A showing an upper portion of the same tool 10 in three successive stages
of operation
(as hereinafter further explained), with corresponding Figs. 2B, 3B, and 4B
showing the lower
portion of the same tool 10 in the same three successive stages of operation.
As may be seen, tool 10 is adapted for insertion in a wellbore casing (not
shown),
and comprises an elongate substantially cylindrical member 20. Cylindrical
member 20
possesses a hollow bore 16 for receiving pressurized abrasive fluid and a frac
fluid (which in
one particular embodiment, as mentioned above, may be one and the same fluid),
and further
possesses an outer periphery 17. A cylindrical hollow slidable sleeve 14 is
positioned within
bore 16, adapted for longitudinal slidable movement along bore 16 in a
reciprocating
manner.
One or more jet ports 18 are provided in outer periphery 17 which are
configured to
direct a stream of pressurized abrasive fluid, typically a fluid containing
quantities of sand
and/or silica granules, radially outwardly from the tool 10, for impacting and
creating
perforations in a surrounding wellbore casing. Jet ports 18, typically two or
more being
located at a similar longitudinal position along cylindrical member 20 as
shown in Figs. 2A-
4A and 6A-8A, typically comprise jet nozzles 18' of hardened steel having an
single aperture
therein, which are threadably inserted into periphery 17 of tool 10 and are
retained in
periphery 17 by threaded bosses 19.
In one preferred embodiment the diameter of an exit aperture in each jet
nozzle 18' is
0.0241 inches (0.61 mm) for creating perforations in the wellbore casing of
similar size. At
pressures of approximately 3,000psi (20,685kPa), with production wellbore
casing
thicknesses of IA inch (6.35mm) (Schedule 20) carbon steel for a nominal 8.625
inch (193mm)
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o.d. casing, with fine silica sand of 20-40 API mesh size (0.84-.42mm) (ie.
diameter less than
0.241 inch) and three nozzles, the penetration time using a jet nozzle 18'
will take in the range
of 30 seconds to create a perforation of desired size in the casing. A similar
time to perforate
a wellb ore casing exists when the casing is of cement as opposed to carbon
steel.
The size of perforations desired to be created in wellbore casing (which is in
turn
dependent upon, inter alia, the characteristics (temperature, viscosity, and
physical properties
of the actual hydrocarbons which are being recovered from the underground
formation ) will
determine the size of the aperture of each nozzle 18". Typically two, and up
to four, jet
nozzles 18' will be located at a similar longitudinal position on periphery 17
of cylindrical
member 20. For optimum adaptability of tool 10, threaded bosses 19 on
periphery 17 to tool
10 in which the jet port nozzles 18' are threadably inserted are adapted to
receive a variety of
nozzles 18' of varying apertures diameters, depending on the size of the
perforations desired
to be created in the wellbore casing.
Fluid communication between jet ports 18 (jet nozzles 18') and inner bore 16
is
regulated by slidable sleeve 14, which when slidably positioned over jet ports
18 prevents
fluid communication between bore 16 and jet ports 18, effectively closing the
jet ports 18.
Movement of slidable sleeve 14, either by: (i) application of an uphole force
to draw slidable
sleeve 14 upward (ref. Fig. 3A), (ii) use of a "pick-up" tool (not shown) ,
inserted downhole
into bore 16 when tool 10 is at a location along a wellbore where a
perforation therein is
desired to be created, or (iii) by injection of a pressurized fluid in bore 16
which thereafter
enter chamber 22 and causes slidable sleeve 14 to act as a piston (ref. Fig.
7A, 8A) so as to
thereby be caused to move so as to open jet port 18, are all alternative and
different ways in
which slidable sleeve 14 may be actuated to respectively allow and prevent
fluid access from
bore 16 to jet ports 18.
In the embodiment of the invention shown in Fig.'s 2A, 3A, and 3B, slidable
sleeve
14 is guided by a pin member 24 travelling in longitudinal slot 26 to ensure
longitudinal
guided movement of slidable sleeve 14 within cylindrical member 20 and bore
16, and to
provide extremities of movement for such slidable sleeve 14.
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An uphole packer member 30 is situated on a portion of periphery 17 of tool
10,
downhole of jet ports 18. An expandable chamber 40 and associated piston
member 41 are
provided , wherein chamber 40 is adapted to receive fluid under pressure from
bore 16 and
cause said associated piston member 41, when pressurized fluid is supplied to
bore 16, to
compress and outwardly expand uphole packer member 30 to create a seal in the
wellbore,
between the tool and the wellbore casing.
A downhole packer member 32 is further provided, situated on a portion of
periphery 17 of tool 10 downhole from uphole packer member 30, as shown in
Figs. 1, 2B,
3B, & 4B. Downhole packer member 32 is typically comprised of an elastomeric
substance,
and in uncompressed when in a non-activated state, as shown in Fig. 2B & 3B.
Upon high
pressure fluid, such as a fracking fluid, being provided to bore 16, such high
pressure fluid
flows into chamber 40 via aperture 43 in piston member 41 causing expansion of
chamber 40.
Expansion of chamber 40 causes piston member 41 to compress downhole packer
member 32,
thereby creating a seal between tool 10 and wellbore casing at the location of
downhole
packer member 32 in the wellbore.
One or more frac ports 50 are provided on tool 10 circumferentially about the
periphery 17 of cylindrical member 20. Frac ports 50 are located on tool 10
intermediate
uphole packer member 30 and downhole packer member 32.
A slidably moveable guide member 60, having radially protruding slip members
62
which frictionally engage the wellbore casing when tool 10 is inserted in the
casing, is
provided. Guide member 60 is situated on tool 10 downhole of downhole packer
member 32.
Guide member 60 is further provided with radially expandable jaw members 78,
on an uphole
side thereof, as shown in Figs. 2B, 3B & 4B.
A 'I- slot subassembly 80 is provided on tool 10, situated downhole of
downhole
packer member 32. 'J'-slot subassembly 80 comprises an inner mandrel member
64, having a
slotted profile "P" therein, and a pin member 65 which travels in slotted
profile "P".
When the 'j'-slot subassembly 80 is in the 'run' position (ref. Fig. 2A, 2B,
and Fig.
6A) and downward force is applied to tool 10 guide member 60 frictionally
engages the
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wellbore casing. In such "run" position , the slotted profile "P in associated
mandrel member
64 does not allow further relative downward movement of a wedge-shaped lower
portion 90
of downhole packer member 32, and thus does not allow jaw members 78 to become
actuated.
When an upward pulling force is applied to tool 10 (ref. Fig. 3A, 3B, and Fig.
7A)
and thereafter a downward force is re-applied to said tool 10 (ref. Fig. 4A,
4B, and Fig. 8A) ,
the 'j'-slot subassembly becomes configured in the 'set' position where :
(i) the wedge-shaped lower portion 90 of downhole packer member 32 is
allowed further downward downhole movement to allow said lower portion 90 to
be forced
against jaw members 78 so as to expand them radially outwardly to engage the
wellbore
casing, and thereby fix the tool 10 within the wellbore casing to allow
fracking to be carried
out.
In a preferred embodiment a bypass port 94 is provided, uphole of the downhole
packer member 32, configured when open to provide fluid communication between
an
exterior of tool 10 and interior bore 16 and permit fluid exterior to tool 10
and above said
downhole packer member 32 to flow into said bore. With such bypass port 94 the
tool 10
may be more easily pulled uphole than would otherwise be the case. A slidable
valve
member 95 slidably opens and closes said bypass port 94.
When an upward force is exerted on the tool 10 slidable valve member 95 is in
an
open position thereby keeping open bypass port 94. When subsequently actuating
said
slot subassembly 80 to the 'set' position by subsequent downward force on tool
10, and/or
frac pressure is applied to bore 16, slidable valve member 95 is moved to a
closed position
thereby closing bypass port 94.
In the embodiments of the tool shown in Fig's 2B, 3B, & 4B , the slidable
valve
member 95 which is provided is moved to the closed position in Fig. 4B, by
hydraulic frac
fluid being applied to bore 16, which thereby moves spring-biased conical
deflector 97
downhole, thereby moving slidable valve member 95 to cover and thereby close
bypass port
94. In an alternative configuration (not shown) mandrel 64 may further or
alternatively be
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configured, to that when the "j'-slot subassembly 80 is in the "set" position,
that bypass port
94 is thereby closed, either by mandrel 64 itself, or by mandrel 64 actuating
slidable valve
member 95 to close bypass port 94.
Numerous other configurations to effectively close bypass port 94 upon T slot
subassembly 80 moving to the "set" position (as shown in Fig. 4B) will now
occur to persons
of skill in the art, and all such variations are within the contemplation of
this invention.
Similarly, conical deflector 97 is shown in Figs. 2B, 3B, & 4B as being biased
by a helical
coil spring 99 to, unless a fluid pressure is supplied to bore 16, allow
conical deflector 97 to
leave slidable valve member 95 in a position where bypass port 94 open. Other
means of
biasing conical deflector 97, other than by spring means, to accomplish the
aforesaid result
will now occur to persons of skill in the art, and such permutations and
substitutions are
likewise contemplated as forming the invention described herein.
Fig's 6A,7A, 8A show successive operation of an alternative embodiment of the
upper
portion of the tool 10 (the bottom portion of the tool 10 being identical to
the configurations
successively depicted in corresponding successive Fig.'s 2B, 3B, & 4B) in
particular with
regard to the manner of actuation of the sliding sleeve 14, where such
embodiment is
specifically adapted to both perforate and frac at the same time.
The components of the bottom portion of the tool 10, for the embodiment shown
in
successive Fig.'s 6A,7A, & 8A, are identical and correspond to the
configuration shown in
corresponding successive Fig.'s 2B, 3B, and 4B. Specifically, Fig. 6A (and
corresponding
bottom portion of the tool 10 in such embodiment shown in Fig. 2B) shows the
tool 10 of
such embodiment in the "run in" position. Fig. 7A (and corresponding bottom
portion of the
tool 10 in such embodiment shown in Fig. 3B) shows the tool 10 of such
embodiment in the
"pulling" position. Lastly, Fig. 8A (and corresponding bottom portion of the
tool 10 in such
embodiment shown in Fig. 4B) shows the tool 10 of such embodiment in the "set"
position.
In such alternative embodiment shown in Fig. 6A, 7A, and 8A, slidable sleeve
14
has a port 23 therein and is configured so as to form a chamber 22. After the
tool 10 is moved
slightly uphole to the "pulling" position shown in Fig's 7A & 3B) and then
moved
downwardly to allow the 'j'-slot to move to the "set" position (ref. Fig. 8A &
4B) pressurized
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abrasive fluid is the supplied to bore 16 of tool 10 . Such pressurized fluid
enters chamber 22
via port 23 and causes slidable sleeve 14 to automatically move uphole as
shown in Fig. 8A,
thereby uncovering jet port 18 to thereafter allow the perforation operation
to be performed. In
this alternative embodiment/alternative method, the pressurized abrasive fluid
also serves as
the fracking fluid. In such case, the foregoing embodiment allows simultaneous
creation of
an uphole perforation in the wellbore casing when such sliding sleeve 14 is
opened, while at
the same time fracking of the formation being simultaneously conducted by a
lower portion of
the tool 10, since upper and lower packer members 30, 32 respectively now
"straddle" an
earlier-created perforation in the wellbore casing, and pressurized
abrasive/fracking fluid is
injected into the formation via such lower earlier-created perforation.
In the preferred embodiments of the upper portion of the tool 10 shown in
Figs. 2A,
3A, & 4 A, and 6A, 7A, & 8A, such upper portion 10 is provided with an annular
cup seal
100 on periphery 17 of tool 10. Such annular cup seal 100 is situated
intermediate jet port
18 and said downhole packer member 32, and serves to reduce flow of abrasive
pressurized
fluid and associated wellbore casing cuttings downhole during the casing
perforation
operation, which is part of the method of the present invention more fully
explained below.
Manner of Operation of Tool, and Methods for perforating wellbore casing and
fracking a
formation using the single tool
A broad outline of a method for operating the tool 10 and methods for
perforating a
wellbore casing and fracking a formation using a single tool 10 are set out
below and are
depicted successively in Figs. 2A,2B, 3A,3B & 4A,4B, and likewise successively
for the
alternative embodiment shown in Fig.'s 6A, 7A & 8A (with corresponding lower
portions of
the tool 10 shown respectively in Fig's 2B, 3B, & 4B).
In the method, broadly described, tool 10 is initially run into a wellbore
casing to a
desired depth in the wellbore casing. During such run-in, and as shown in Figs
2A, 2B and
Fig. 6A, slidable sleeve 14 covers jet port 18. Frac port 50 may be in an open
or closed
position, and likewise for bypass port 94 may be in an open or closed position
( but is shown
in the open position in Figs. 2B, 3B). Thereafter, when the tool 10 has been
lowered to the
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lowermost portion of the wellbore which is desired to be perforated and
fracked, slight
upward movement of tool 10 (ref. Fig.'s 3A, 3B) pulls slidable sleeve 14
uphole, while guide
member 60 and slips 62 thereon generally keep the remainder of tool 10 at a
fixed position
within the wellbore, thusly opening jet port 18 and jet nozzles 18'.
An abrasive pressurized fluid containing an abrasive compound such as
uniformly
sized sand particles or tungsten carbide filings of small uniform dimension,
is then injected
into bore 16 . Such fluid not only enters chamber 40 through port 43 and
caused piston 41 to
compress uphole packer member 30 to thereby create a seal between tool 10 and
the wellbore
casing at such location, thereby preventing flow of abrasive fluid downhole,
at such time the
pressurised fluid is further expelled in a radially outward manner from jet
ports 18 and jet
nozzles 18' to thereby impinge upon the wellbore casing, and after a short
time interval of
impingement, perforate the casing at such location, with perforations equal in
number to the
number of jet ports 18 (ref. Figs. 3A, 3B)
It is noted that slidable sleeve 14 in the method of the present invention
need not
necessarily be opened by slight upward force on the tool string and tool 10,
as described
above, but rather in an alternative embodiment shown in Fig. 6A, 7A, and 8A,
such slidable
sleeve 14 is configured so as to form a chamber 22, and is opened by
pressurized fluid being
supplied to such chamber 22. This variation is described further below.
After the above perforation operation is performed, injection of pressurized
abrasive
fluid is ceased, and tool 10 may then be further drawn uphole to thereby
position both the
uphole packer member 30 and the lower (downhole) packer member 32 of tool 10
on the
uphole and downhole side, respectively, of the created perforation, so as to
effectively
"straddle" the perforation with packer members 30, 32.
Thereafter, and as shown in Fig. 4A&B, further downward force is re-applied
reapplied to the tool 10 to move slidable sleeve 14 downward (downhole) to
cover jet ports
18 and to further actuate 'j' slot subassembly to allow wedge-shaped lower
portion 90 of
lower packer member 32 to be forced against jaw members 78, thereby causing
such jaw
members 78 to be forced radially outwardly and thus against the wellbore
casing so as to
thereby temporarily secure tool 10 within the wellbore casing. Simultaneously,
by downhole
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packer member 32 being forced against jaw members 78 of guide member 60, the
downhole
packer member 32 is compressed and caused to expand radially outwardly,
thereby creating a
seal between the tool 10 and the wellbore casing at that location.
Thereafter, as shown in Fig. 4A&B, pressurized fracking fluid is injected into
bore
16, which causes piston member 41 in said tool 10 to compress said uphole
packer member
30 and cause said uphole packer member 30 to expand radially outwardly, and
thereby
cause the pressurized fluid to pass into said the created perforation via frac
port 50 in tool
10.
Thereafter, after completion of the fracking of the wellbore and this
particularly
location, supply of the pressurized fracking fluid is ceased and an upward
force is then re-
applied to the tool 10 to disengage jaw members 78 and allow re-positioning of
tool 10
further uphole for creating further perforations and injecting further
fracking fluid into further
created perforations at such locations.
Fig. 5 shows a further elaboration/itemization of one particular method 400 of
the
present invention, using the tool 10 configuration shown in Figs. 2A,B, 3A,
3B, & 4A, 4B,
and where a bypass port 94 further is utilized .
In step 401, tool 10 is run downhole. Jet port 18 remains closed, and frac
port 50
remains open, and neither upper packer member 30 or lower packer member 32 are
"set" (i.e.
compressed), thereby allowing the tool 10 to be run in into the wellbore, to a
desired lowest
depth where perforations and fracking is desired to be conducted. The T slot
subassembly 80,
namely pin member 65 within slot "P" of mandrel 62, is in the "run in"
position as shown in
Fig. 2B
If there is an existing perforation in the wellbore, the operator will, as
shown in step
402, elect to proceed to step 403 to pull up slightly on the tool 10 to move
the j-slot 80 from
the run-in" position to the "pulling position" as shown in Fig. 3B, to thereby
align frac port 50
proximate the perforation, and thereby also open bypass port 94 (If no
existing perforation,
the operate will proceed with step 407, described below). Thereafter, in step
404 the operator
will push tool 10 slightly back down in the wellbore , to move T slot
subassembly 80 to the
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"set" position (ref Fig. 4B), and simultaneously set (ie. compress) the lower
packer member
32 and jaw members 78, close bypass port 94, and close jet port 18.
In subsequent step 405, pressurized frac fluid is then supplied to bore 16 to
tool 10,
to "set"(i.e. compress) upper packer member 30 by movement of piston 41, and
frac fluid is
injected into the formation in the region of the created perforation by supply
of frac fluid to
frac port 50 and thereby to the formation.
After fracking, tool 10 is pulled uphole in step 407 to thereby open jet port
18 and
bypass port 94, release lower packer 32 and jaw member 78, and allow movement
of tool 10
to an uphole location in the wellb ore were desire to further perforate the
casing.
In subsequent step 408, abrasive fluid is supplied to bore 16 of tool 10 , and
subsequently through jet port 18 to perforate the wellbore casing at such new
uphole position,
and thereafter the supply of such abrasive pressurized fluid is ceased.
In subsequent step 409, the tool 10 is pulled further uphole to position frac
port 50
over the newly created perforation, and move T- slot 80 to the "pulling"
position.
If the desired length of the wellbore has not been completely perforated and
fracked ,
the completion engineer reverts to step 404, and re-execute steps 404- 409 at
such further
location in the wellbore.
Otherwise, if at such point the wellbore has been completely
perforated and fracked to the extent desired, the tool 10 can then be removed
from the
wellbore.
The operation of the configuration of tool 10 , having the configuration shown
in Fig's
6A, 7A, & 8A, allows both perforation and fracking to be simultaneously
carried out , and
necessarily involves the abrasive fluid being one and the same as the frac
fluid.
Such further refinement to the method 400 comprises simultaneously with step
405
injecting the abrasive /frac fluid, causing, by injection of such
abrasive/frac fluid, the slidable
sleeve 14 to move to an open position and expelling said abrasive/fracking
fluid in a radially
outward manner via said jet port 18 to thereby create a further perforation in
the wellbore.
Step 409 further comprises the step of repositioning the tool 10 further
uphole so as to further
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position upper packer member 30 the further created perforation, and again
supplying the
abrasive/fracking fluid to tool 10 when in such further position, to frac the
formation in the
region of the further perforation in the wellbore, and at the same time to
further create an
additional uphole perforation.
The foregoing description of the disclosed embodiments is provided to enable
any
person skilled in the art to make or use the present invention. The scope of
the claims should
not be limited by the preferred embodiments set forth in the examples, but
should be given the
broadest interpretation consistent with the description as a whole. Thus, the
present invention
is not intended to be limited to the embodiments shown herein, but is to be
accorded the full
scope consistent with the claims, wherein reference to an element in the
singular, such as by
use of the article "a" or "an" is not intended to mean "one and only one"
unless specifically so
stated, but rather "one or more". In addition, where reference to "fluid" is
made, such term is
considered meaning all liquids and gases having fluid properties, as well as
semi-solids such
as tar-like substances.
For a complete definition of the invention and its intended scope, reference
is to be
made to the summary of the invention and the appended claims read together
with and
considered with the disclosure and drawings herein.
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