Note: Descriptions are shown in the official language in which they were submitted.
CA 02795641 2012-09-19
WO 20121059859 PCT/1B2011/054841
METHOD AND APPARATUS FOR COMPLETION OF HEAVY OIL
UNCONSOLIDATED SAND RESERVOIRS
FIELD OF THE INVENTION
The present invention relates generally to methods and systems for enhancing
heavy oil productivity from unconsolidated sand reservoirs and, in illustrated
embodiments thereof, more particularly relates to a method and apparatus for
completion of heavy oil unconsolidated sand reservoirs.
BACKGROUND OF THE INVENTION
Heavy oil production with sand is becoming an increasingly used technique
for certain types of heavy oil deposits. Allowing sand production can
dramatically
improve oil recovery compared to the non-sand production process. The
advantage of
allowing sand production is that the produced sand creates high permeability
zones
comprising of relatively small channels for the heavy oil to flow through.
However, a
challenge with heavy oil production with sand is keeping the sand moving
freely and
consistently into the wellbore.
Conventional, explosive charge well perforation or completion which creates
relatively small diameter holes in the well casing for the production of
formation fluid
from the reservoir has experienced sporadic success with heavy oil production
with
sand. This is attributed to experiencing in-flow problems caused by fine sand
and clay
migration or reservoir sand sloughing that plugs the small diameter casing
holes
created by the explosive charge perforation completion process.
In an attempt to improve well productivity, and to alleviate the plugging
problems associated with conventional explosive charge perforation, horizontal
drilling and horizontal radial water-jetting methods have been implemented in
the
completion of unconsolidated sand reservoirs. However, each of these methods
has
achieved nominal success. It is believe the low success is attributed to
performing
these methods in an overbalanced condition, that is, in a condition in which
fluid
pressure in the wellbore is maintained higher than the pressure of the
reservoir. In this
condition, sand loosened from the horizontal drilling and horizontal radial
water-
jetting is pushed back into the reservoir. It is believed this causes
instability in the
I
CA 02795641 2012-09-19
WO 20121059859 PCTIIB20111054841
manufactured bores and results in eventual collapse or closure of the channel
due to
sand sloughing.
Considering the advantage of high permeability verse the challenge of high
sand production in heavy oil unconsolidated sand reservoirs a need exists for
an
improved completion method and apparatus that provides an unrestricted near
well-
bore access in heavy oil sand producing wells. It is to this need that the
present
invention is directed.
SUMMARY OF THE INVENTION
In carrying out the principles of the present invention, in accordance with
representative embodiments thereof, a well casing perforation and formation
boring
tool and methods of the same for the completion of a subterranean well, and
particularly, a heavy oil unconsolidated sand reservoir in an underbalanced
condition
is provided.
Embodiments of the present invention also provide for a low impact
completion when compared to conventional explosive charge completions, which
alleviate concern of damaging cement encasement that is critical in providing
isolation from water zones above or below the productive formation.
Embodiments of the present invention further provide tools and methods for
forming a large well-bore access area and a high permeability lateral bore or
cavern
deep within the reservoir providing enhanced connection between the well and
reservoir. The large sand face or reservoir contact area provided by the high
permeability bore reduces reservoir fluid velocities and is believed to
minimize or
eliminate problematic sand and clay production.
Embodiments of the present invention further provide tools and methods that
can be implemented on existing completed wells that are experiencing
problematic in-
flow or poor production due to near well bore formation damage.
To achieve these and other advantages, in general, in one aspect, a method of
completing a subterranean well extending through an earth formation is
provided,
including the steps of. creating an underbalanced condition in the well;
providing a
nozzle in the well; and pumping a pressurized fluid through the nozzle such
that a jet
2
CA 02795641 2012-09-19
WO 2012/059859 PCT/1B2011/054841
of the pressurized fluid ejects from the nozzle and impinges on the earth
formation
creating a lateral bore in the earth formation.
The method may further include the steps of: providing a flexible hose to
which the nozzle is attached and extending the flexible hose fitted with the
nozzle into
the earth formation from the well.
In general, in another aspect, a method of completing a subterranean well
having a well casing extending though an earth formation is provided,
including the
steps of: suspending an apparatus at a selected depth within the well casing;
creating
an unbalanced condition within the well casing; forming a lateral bore in the
formation by jetting a pressurized fluid from the apparatus through a casing
opening
in the well casing and into the earth formation; receiving in the well casing
through
the casing opening fluid and formation debris created from forming the lateral
bore;
and lifting the fluid and formation debris received by the well casing
upwardly
through the well casing to the well surface.
In general, in another aspect, a method of completing a subterranean well
having a well casing extending through an earth formation is provided,
including the
steps: providing a well perforation and completion tool including a body
having a
circumferential wall, an internal axial flow passage extending through an end
of the
body and terminating through the circumferential sidewall forming a side port,
one or
more lateral ports extending through the circumferential wall and providing
fluid
communication between the internal axial flow passage and a position
exteriorly of
the body, and an abrasive jet perforation nozzle disposed in each of the
lateral ports;
suspending the well perforation and completion tool at a selected depth within
the
well casing; pumping a high pressure abrasive fluid through the internal axial
flow
passage such that a jet of the high pressure fluid ejects out of each of the
perforation
nozzles to form a perforation in the well casing; moving the well perforation
and
completion tool in the well casing while maintaining the azimuth position of
the well
perforation and completion tool relative to the well casing while pumping the
high
pressure fluid to form a casing slot through the well casing; configuring the
well
perforation and completion tool for well completion; creating an underbalanced
condition in the well casing; extending a hose having attached thereto an
excavation
nozzle from the apparatus through the side port and through the casing slot
and into
3
CA 02795641 2012-09-19
WO 2012/059859 PCT/1B2011/054841
the earth formation; and pumping a pressurized excavation fluid through the
hose
such that a jet of the pressurized excavation fluid ejects out of the
excavation nozzle
and impinges the earth formation to form a lateral bore in the earth formation
while
extending the hose.
In general, in another aspect, a casing perforation and formation boring tool
for use in connection with the completion of a subterranean well is provided,
the tool
including: a body having a circumferential wall, an internal axial flow
passage
extending through an end of the body and terminating through the
circumferential
sidewall forming a side port, one or more lateral ports extending through the
circumferential wall and providing fluid communication between the internal
axial
flow passage and a position exteriorly of the body, and a landing scat
disposed across
the internal axial flow passage at a position between the one or more lateral
ports; the
internal axial flow passage configured to receive a tube therein; the landing
seat
configured to receive a blanking plug to isolate the one or more lateral ports
from the
side port; and an abrasive perforation nozzle disposed in each of the one or
more
lateral ports.
In an aspect, the tool may also include a flexible hose disposed and
extensible
within the internal flow passage; a hydraulic excavation nozzle connected to a
downhole end of the flexible hose; and a guide wheel guiding the distal end of
the
flexible hose through the side port.
In an aspect, the tool may also include a pipe disposed within the internal
axial
flow passage; a pipe coupling connect to an top hole end of the pipe; and a
hydraulic
excavation nozzles connected to a downhole end of the pipe, the hydraulic
excavation
nozzle aligned with the side port and configured to jet a stream of
pressurized fluid
flowing through the pipe.
In an aspect, the tool may also include an alignment tab carried by the body
and extensible between a retracted position and an extended position.
There has thus been outlined, rather broadly, the more important features of
the invention in order that the detailed description thereof that follows may
be better
understood and in order that the present contribution to the art may be better
appreciated.
4
CA 02795641 2012-09-19
WO 2012/059859 PCT/182011/054841
Numerous objects, features and advantages of the present invention will be
readily apparent to those of ordinary skill in the art upon a reading of the
following
detailed description of presently preferred, but nonetheless illustrative,
embodiments
of the present invention when taken in conjunction with the accompanying
drawings.
The invention is capable of other embodiments and of being practiced and
carried out
in various ways. Also, it is to be understood that the phraseology and
terminology
employed herein are for the purpose of descriptions and should not be regarded
as
limiting.
As such, those skilled in the art will appreciate that the conception, upon
which this disclosure is based, may readily be utilized as a basis for the
designing of
other structures, methods and systems for carrying out the several purposes of
the
present invention. It is important, therefore, that the claims be regarded as
including
such equivalent constructions insofar as they do not depart from the spirit
and scope
of the present invention.
is For a better understanding of the invention, its operating advantages and
the
specific objects attained by its uses, reference should be had to the
accompanying
drawings and descriptive matter in which there is illustrated embodiments of
the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The following drawings illustrate by way of example and are included to
provide further understanding of the invention for the purpose of illustrative
discussion of the embodiments of the invention. No attempt is made to show
structural details of the embodiments in more detail than is necessary for a
fundamental understanding of the invention, the description taken with the
drawings
making apparent to those skilled in the art how the several forms of the
invention may
be embodied in practice. Identical reference numerals do not necessarily
indicate an
identical structure. Rather, the same reference numeral may be used to
indicate a
similar feature ofa feature with similar functionality. In the drawings:
Figures lA-C are cross-sectional views of successive axial portions of a well
casing perforation and formation boring tool embodying principles of an
embodiment
5
CA 02795641 2012-09-19
WO 2012/059859 PCT/IB2011/054841
the present invention, the tool being shown*in a first configuration for well
casing
perforation;
Figures 2A-B are cross-sectional views of successive axial portions of the
well
casing perforation and formation boring tool of FIGS. I A-C, the tool being
shown in a
second configuration for formation boring;
Figures 3A-C are cross-sectional views of successive axial portions of a well
casing perforation and formation boring tool embodying principles of another
embodiment the present invention, the tool being shown in a first
configuration for
well casing perforation;
Figures 4A-B are cross-sectional views of successive axial portions of the
well
casing perforation and formation boring tool of FIGS. 3A-C, the tool being
shown in a
second configuration for formation boring;
Figure 5 is a schematic well diagram illustrating a method of perforating a
well casing of a subterranean well, the method embodying principles of an
embodiment of the invention;
Figure 6 is a schematic well diagram illustrating a method of boring a channel
into a subterranean formation from the well, the method embodying principles
of an
embodiment of the invention;
Figure 7 is a diagrammatic perspective view of an exemplary hydraulic
excavation nozzle;
Figure 8 is a diagrammatic rear view of the hydraulic excavation nozzle of
FIG. 7;
Figure 9 is a schematic tool diagram embodying principles of an embodiment
the present invention; and
Figure 10 is a schematic tool diagram embodying principles of an embodiment
of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
As a preliminary matter, it should be noted that in this document (including
the claims) directional terms, such as "above", "below", "upper", "lower",
etc., are
used for convenience in referring to the accompanying drawings. Additionally,
it is to
be understood that the various embodiments of the invention described herein
may be
6
CA 02795641 2012-09-19
WO 2012/059859 PCT/1B2011/054841
utilized in various orientations, such as inclined, inverted, horizontal,
vertical, etc.,
without departing from the principles of the invention.
Representatively illustrated in FIGS. 1 A-C is a well casing perforation tool
and formation boring tool 10 in accordance with an embodiment of the
invention.
Tool 10 is shown in a well casing perforation configuration and includes a
tool body
12 having an abrasive jet perforation sub 14, a landing nipple 16, a jetting
shoe 18 and
a wiper sub 20 each disposed coaxially and in series from the abrasive jet
perforation
sub to the wiper sub. Body 12 further includes an internal axial flow passage
22
extending through the abrasive jet perforation sub 14, the landing nipple 16
and
partially through the jetting shoe 18 where the internal axial flow passage
includes a
lateral bend and extends through the circumferential wall of the jetting shoe
forming a
side port 24.
The abrasive jet perforation sub 14 has at least one, and preferably has a
plurality of lateral ports 26 extending through the circumferential wall
thereof. In one
embodiment, there are three lateral ports 26 arranged in a triangular
configuration. In
another embodiment, there are four lateral ports 26 arranged in a boxed or
diamond
configuration. The lateral ports 26 provide fluid communication between the
internal
axial flow passage 22 and a position exteriorly of the abrasive jet
perforation sub 14.
An abrasive jet perforation nozzle 28 is disposed in each of the lateral ports
26 for the
passage of the high pressure abrasive cutting fluid used to cut a slot into
the well
casing and cement encasement as will be further described below. Lateral ports
26
and nozzles 28 are preferably configured to cut a one-inch wide slot through
the well
casing and cement encasement.
Further, it is of importance to note, the lateral ports 26 and the side port
24 are
disposed on the same side of body 12 and are generally vertically aligned
about the
circumference of the body.
Landing nipple 16 connects the abrasive jet perforation sub 14 and the jetting
shoe 18 and provides a landing seat 30 across the internal axial flow passage
22 for
the reception of a removable blanking plug 40 to seal the internal axial flow
passage
and isolate the jetting shoe from a flow of fluid through the internal axial
flow
passage in a well casing perforation operation as will be described in further
detail
7
CA 02795641 2012-09-19
WO 2012/059859 PCT/1B2011/054841
below. The blanking plug 40 may include a fishing neck 41 to permit retrieval
of the
blanking plug through known methods.
Jetting shoe 18 is configured to receive the passage of an extensible
hydraulic
excavator (FIGS. 2A-C) that includes a flexible high pressure hose fitted with
a high
pressure fluid nozzle that is run-in from the well surface in a formation
boring
operation as will be described in further detail below. The jetting shoe 18
includes a
hose guide wheel 32 that is rotatably supported by the body 12 and partially
intersects
with the internal axial flow passage 22. The guide wheel 32 serves to guide
the
flexible high pressure hose run through the internal flow passage 22 with the
side port
24 where it can be extend through the side port and into the formation during
said
formation boring operation.
Jetting shoe 18 further includes an extensible alignment tab 34 that laterally
moves relative to the jetting shoe between a retracted position, shown in FIG.
2, and
an extending position for registration with a perforation slot cut into the
well casing
by the abrasive jet perforation sub 14 during said well casing perforation
operation. In
an embodiment, the alignment tab 34 is biased into the extended position. The
alignment tab 34 may be spring biased by one or more coil springs 36. In a
preferred
embodiment, alignment tab 34 is disposed vertically below side port 24 with
reference
to the orientation of the tool 10 as illustrated in the figures. It is
important to note,
alignment tab 34 is located along the same side of body 12 as the lateral
ports 26 and
the side port 24 and is generally vertically aligned about the circumference
of the
body with the lateral ports and the side port.
Wiper sub 20 is attached to the bottom of the jetting shoe 18 and includes one
or more radially extending seal members 38. The seal member 38 is configured
to
making a circumferential sealing contact with the internal surface of the well
casing
and provides well casing isolation from lower completion zones.
In FIGS. 2A-B, tool 10 is illustrated in a second configuration which is a
formation boring configuration, wherein the blanking plug 40 is removed and an
extensible hydraulic excavator 42 is disposed in the internal axial fluid
passage 22.
The extensible hydraulic excavator 42 includes a high pressure flexible hose
44
having a hydraulic excavation nozzle 46 fitted at its distal end and is
connected at the
opposite end to coiled tubing 48. The high pressure flexible hose 44 is
disposed about
8
CA 02795641 2012-09-19
WO 2012/059859 PCT/182011/054841
guide wheel 32 with the hydraulic excavation nozzle 46 aligned with side port
24. As
will be further described, advancement of the coiled tubing 48 at the surface
of the
well causes the high pressure flexible hose 44 to extend from the jetting shoe
18
through side port 24 as illustrated in dashed line. Similarly, retraction of
the coiled
tubing 48 causes the high pressure flexible hose 44 to retract into the
jetting shoe 18.
Rotating guide wheel 32 ensures the high pressure flexible hose 44 is extended
and
retracted through side port 24 without being kinked or snagged by the jetting
shoe 18.
An alternate embodiment 18a of the jetting shoe 18 is shown in FIGS. 3A-C
and is incorporated in an alternate embodiment 10a of the previously described
tool
10. In FIGS. 3A-C, tool lOa is illustrated in the well casing perforation
configuration.
Further, like reference numbers refer to similar elements of the embodiments,
and
accordingly, to avoid duplication will not be described here. Jetting shoe 18a
is
devoid of guide wheel 32 and opposed to an extensible hydraulic excavator,
jetting
shoe I8a is fitted a fixed hydraulic excavator 50 that is disposed within
internal axial
flow passage 22. Fixed hydraulic excavator 50 includes a fixed stand pipe 52
fitted at
the top or surface end with a coil on/off tool 54 and at the opposite end a
high
pressure hydraulic excavation nozzle 56. The coil on/off tool 54 permits the
downhole connection of a coiled tube with the stand pipe 52 for the delivery
of a high
pressure fluid to the excavation nozzle 56. The excavation nozzle 56 is
fixedly
disposed at side port 24 and is directed to eject a high pressure stream from
the side
port towards the formation in a formation boring operation.
In FIGS. 4A-13, tool I Oa is illustrated in a second configuration which is a
formation boring configuration, wherein the blanking plug 40 is removed and
the
stand pipe 52 of the fixed hydraulic excavator 50 is connected by coil on/off
tool 54 to
a length of coiled tubing 58 run into the internal axial flow passage 22.
Turning now to FIG. 5, well casing perforation will be described utilizing
tool
10 configured in the well casing perforation configuration that is illustrated
in FIGS.
I A-C and discussed above. In FIG. 5, there is schematically illustrated a
conventional
well bore 60 having a well casing 62 and cement encasement 64 extending
through an
oil bearing formation 66, and particularly, a heavy oil unconsolidated sand
formation.
Tool 10 is schematically illustrated for purpose of illustrative clarity, and
is connected
to a distal end of a length of upset tubing 68 or the like at the top end of
the abrasive
9
CA 02795641 2012-09-19
WO 2012/059859 PCT/1B2011/054841
jet perforation sub 14. Tool 10 is lowered into the well casing 62 by tubing
68 to a
depth at which it is desired to perforate the well casing and the cement
encasement 64
and complete a lateral bore into the adjacent formation 66. Once the tool 10
is
positioned at the desired depth, a high pressure abrasive fluid 70 is pumped
through
tubing 68 and into the internal axial flow passage 22 of the tool. The
Blanking plug 40
isolates the jetting shoe 18 from the abrasive jet perforation sub 14 causing
the high
pressure abrasive fluid 70 to flow through lateral ports 26 and jet out from
the
perforation nozzles 28 under high pressure and impinge against the wall of the
well
casing 62 and cement encasement 64. Tool 10 is then alternately moved upwardly
(withdrawn) and downwardly (extended) in the well casing 62 to cut a casing
slot 72
through the well casing and cement encasement 64. Tool 10 is moved a distance
corresponding to the desired overall height of the casing slot 72. Once the
casing slot
72 is cut, tool 10 is configured for formation boring by the retrieval of
blanking plug
40 for example, by running length of coiled tubing (not shown) through tubing
68 to
connect to the blanking plug and withdraw it from tool 10 and pull it to the
surface,
thereby permitting running of the extensible hydraulic excavator.
Turning now to FIG. 6, formation boring will be described utilizing tool 10
configured in the formation boring configuration that is illustrated in FIGS.
2A-B and
discussed above. Tool 10 is schematically illustrated for purpose of
illustrative clarity,
and remains connected to tubing 68. Tool 10 is moved upwardly (withdrawn) in
the
well casing 62 causing guide tab 34, which is pressed against the interior
surface of
the well casing via the biasing force of springs 36, to automatically extend
into and
engage casing slot 72 (as shown here). The engagement of the guide tab 34 with
the
casing slot 72 registers the side port 24 of the jetting shoe 18 with the
casing slot.
With the guide tab 34 in this position, the extensible hydraulic excavator 42
is
connected to tubing 48 and comprising hose 44 and nozzle 46 is run-in through
tubing
68 and internal axial flow passage 22. Upon the nozzle 46 reaching the guide
wheel
32, the nozzle and the hose 44 are fed through the side port 24 and through
the casing
slot 72, at which it is positioned and oriented laterally against the
formation 66 in
which a lateral bore radially extending from the well bore 60 is to be
completed.
At this point, the well bore 60 is placed into an underbalanced condition,
wherein the pressure within the well casing 62 is lower than the formation
pressure,
CA 02795641 2012-09-19
WO 2012/059859 PCT/1B2011/054841
by a continuous injection of stable foam through tubing 68 and the internal
axial flow
passage 22 where it is ejected from the side port 24. The stable foam 74 is
returned to
the surface through well casing 62. Once the stable foam 74 is initially
returned to the
surface, pressurized fluid, such as, for example water is then pumped through
tubing
48, through hose 44 and jetted from nozzle 46 where it impinges against the
unconsolidated sand formation 66 forming a lateral bore 76 therein. The
underbalanced condition of the well bore 60, as result of the injection of
stable foam
74, causes sand slurry and fluids, admixed with the stable foam, to flow
outwardly
from the lateral bore 76 and into the well casing 62 through the casing slot
72, Once
in the well casing 62, the sand slurry, fluid and stable foam are further
mixed within a
mixing chamber 78 defined by a lateral recessed profile 80 in the exterior
circumferential wall of the jetting shoe 18 and the well casing 72. The
recessed
profile 80 is further illustrated in FIG. 1 B by the region bounded by the
dashed lines.
At this point, the stable foam, sand and fluid slurry is lifted to the surface
of the well
bore 60.
The hose 44 and nozzle 46 are fed continuously into the unconsolidated sand
formation 66 from the tool 10 until a lateral bore 76 reaches a desired radial
depth
from the well bore 60. The hose 44 and nozzle 46 may be alternately withdrawn
and
extended (guided by guide wheel 32) to achieve the desired radial depth, which
may
be up to 150-feet. As this operation continues, an increasing volume of sand
is flushed
into the well casing 62 creating a high permeability bore 76 deep into the
unconsolidated sand formation 66.
Once bore 76 reaches a desired depth, water jetting injection is terminated,
and
the hose 44 and nozzle 46 are withdrawn into the jetting shoe 18 and the
excavator 42
is withdrawn from tool 10 and pulled to the surface. Stable foam injection
continues
until the surface returns are clear of sand providing an indication that
completion at
this interval is finished, and at which point, the stable foam injection is
terminated.
Tool 10 is then withdrawn slowly causing the alignment tab 34 to be retracted
once it
reaches the top of the casing slot 72. Tool 10 may be withdrawn a certain
distance to
align the tool with another completion zone or may be completely withdrawn
from the
well bore 60. In multiple completions with tool 10, the lowest or deepest zone
would
be completed first with successive zones being completed at the tool is
withdrawn.
11
CA 02795641 2012-09-19
WO 2012/059859 PCT/IB2011/054841
The wiper sub 20 isolates completed zones as the tool 10 is withdrawn and is
operated
to complete a subsequent zone.
The above description in reference to methods of operating tool 10 and the
above description of tool l0a with reference to FIGS. 3A-C and FIGS. 4A-B are
believed to be sufficient to understand the operation of tool 10a. The main
distinction
being the fixed excavator 50 of tool 10a is disposed within the internal axial
flow
passage 22 prior to tool I Oa being run-in to the well casing 62. Of course,
the fixed
excavator 50 does not extend a hose or excavation nozzle radially into the
formation
as does the extensible excavator 42 of tool IOa. Accordingly, tool 10 is
considered to
be primarily used for deep formation penetration and tool I Oa is considered
to be
primarily used for shallow formation penetration.
Further, it should be noted excavation nozzles 46 and 56 may be of any known
type or conventional in the art. In an embodiment, and for example, as
illustrated in
FIGS. 7 and 8, nozzle 46 may include one more thruster discharge ports 78
disposed
on a rearward end of the nozzle. Thruster discharge ports 78 operate to jet
streams of
fluid from the nozzle 46 in a rearwardly direction relative to the nozzle
which causes
the nozzle 46 to be propelled in a forwardly direction. Nozzle 46 also
includes one or
more excavation discharge ports 80 disposed on a forwarded end of the nozzle.
Ports
80 operate to jet streams of fluid from the nozzle 46 in a forwardly direction
relative
to the nozzle for the purpose of hydraulic excavating material disposed
forward of the
nozzle.
With reference to FIG. 9, the jetting shoe 18 can be configured to be run-in
separately of the abrasive perforation sub 14 and the nipple 16, in restoring
or
cleaning operations in existing wells to improve well production by cleaning
casing
perforations or further opening of formation bores. In such a configuration,
tubing 68
would be connected to the jetting shoe 18 to lower the jetting shoe in the
well casing
to the desired depth. Extensible excavator 42 would be operated as discussed
above,
in either an underbalanced or overbalanced well condition. Jetting shoe 18a
can be
configured similarly to jetting shoe 18 as shown in FIG. 10.
A number of embodiments of the present invention have been described.
Nevertheless, it will be understood that various modifications may be made
without
12
CA 02795641 2012-09-19
WO 20121059859 PCT/IB2011/054841
departing from the spirit and scope of the invention. Accordingly, other
embodiments
are within the scope of the following claims.
13
