Note: Descriptions are shown in the official language in which they were submitted.
CA 02589672 2007-05-23
ATTORNEY DOCKET NO.: 25.0337 UTILITY PATENT
ABRASIVE JET CUTTING SYSTEM AND METHOD
FOR CUTTING WELLBORE TUBULARS
FIELD OF THE INVENTION
[0001] The present invention relates in general to wellbore operations and
more particularly to
systems and methods for cutting tubulars in a wellbore.
BACKGROUND
[0002] At various stages in a well's life it may be necessary to cut the
tubulars used in its
construction. This may be required during completion of the well, operation of
the well or upon
abandonment of the well. Reasons for cutting the pipe include without
limitation, cutting a
tubular that is stuck in the wellbore, cutting a window for side tracking the
present wellbore and
cutting fluid pathways.
[0003] Prior art methods for making radial cuts include explosive jet cutters,
chemical cutters
and mechanically cutting with drill pipe or coiled tubing. Each of this
mechanisms and methods
have drawbacks. For example, with regard to explosive cutters, it is difficult
to create clean cuts
and to not damage material behind the cut. Additionally, health and safety
concerns dictate strict
operational procedures be employed when utilizing explosive cutters. With
regard to chemical
cutting tools, the cut depth is limited by the nature of the system and the
completion. With regard
to mechanical cutting, when performed using drill pipe or coiled tubing the
use of a rig is
required; thus increasing time loss and expenses.
[00041 Therefore, it is a desire to provide a cutting tool and method for
creating various types of
cuts in a tubular that address drawbacks of the prior art systems and methods.
It is a further
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desire to provide a cutting tool and method for making radial cuts as well as
window cuts in a
tubular. It is a still further desire to provide a cutting tool and method for
creating various cuts in
a tubular via a wireline.
SUMMARY OF THE INVENTION
[00051 Accordingly, a cutting tool and method for creating a continuous cut in
a tubular that is
positioned in a wellbore is provided.
[00061 An embodiment of a cutting tool, positionable in a tubular for creating
a cut in a tubular,
includes a body securable within the tubular and a cutting head having a
nozzle for discharging a
pressurized cutting fluid, wherein the cutting head is rotationally and
axially moveable relative to
the body. The cutting tool may further include one or more of a positioning
mechanism, a linear
actuator in connection with the cutting head, a rotary actuator in connection
with the cutting
head, a cutting fluid pump, a mechanism for mixing a fluid and an abrasive to
form the abrasive
cutting fluid, and reservoirs for storing the abrasive cutting fluid or for
storing a fluid and the
abrasive separately.
[00071 An embodiment of a method of creating a continuous cut through a
tubular that is
disposed in a wellbore includes the step of positioning a tool in the tubular,
the tool having a
nozzle for discharging a pressurized cutting fluid that penetrates and cuts
the tubular, discharging
the cutting fluid creating an initiation point of a cut through the tubular,
extending the cut from
the initiation point along a first path, and completing the cut.
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Another embodiment relates to a downhole cutting tool positionable in a
tubular of a subsurface wellbore, the downhole cutting tool for creating a cut
in the
tubular and comprising: a body securable within the tubular; and a cutting
unit
comprising: a fluid pump for converting an initial fluid to a pressurized
fluid, and a
cutting head, the cutting head having a nozzle for directing the pressurized
fluid to the
tubular to create the cut in the tubular.
A further embodiment relates to a method of cutting a tubular that is
disposed in a subsurface wellbore comprising: positioning a downhole cutting
tool in
the tubular; actuating a fluid pump, which is disposed in the downhole cutting
tool, to
cause an initial fluid to be converted to a pressurized fluid; and directing
the
pressurized fluid to the tubular to form a cut in the tubular.
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[00081 A further embodiment of a method of creating a continuous cut through a
tubular that is
disposed in a wellbore includes the step of providing a cutting tool including
a positioning
mechanism, an anchoring mechanism, a linear actuator, a rotary actuator, a
cutting fluid pump
and a cutting head having a nozzle for discharging a pressurized cutting fluid
that penetrates and
cuts the tubular; positioning the tool in the tubular; securing the tool in
the tubular; discharging
the cutting fluid creating an initiation point of a cut through the tubular;
extending the cut from
the initiation point along a first path via at least one of the actuators; and
completing the cut.
[00091 An embodiment of completing the continues cut includes continuing the
cut past the
initiation point along the first path to a termination point and then
traversing the cut across the
first path.
[00101 The foregoing has outlined the features and technical advantages of the
present invention
in order that the detailed description of the invention that follows may be
better understood.
Additional features and advantages of the invention will be described
hereinafter which form the
subject of the claims of the invention.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The foregoing and other features and aspects of the present invention
will be best
understood with reference to the following detailed description of a specific
embodiment of the
invention, when read in conjunction with the accompanying drawings, wherein:
[0012] Figure 1 is a schematic of an embodiment of an abrasive jet cutting
tool of the present
invention;
[0013] Figure 2 is an illustration of a linear-radial cut created in a tubular
utilizing an abrasive
jet cutting tool of the present invention;
[0014] Figure 3A is a an illustration of a non-linear cut utilizing an
abrasive jet cutting tool of
the present invention to create a window in a tubular; and
[0015] Figure 3B is an illustration of the completion of the cut of Figure 3A.
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DETAILED DESCRIPTION
[0016] Refer now to the drawings wherein depicted elements are not necessarily
shown to scale
and wherein like or similar elements are designated by the same reference
numeral through the
several views.
[0017] As used herein, the terms "up" and "down"; "upper" and "lower"; and
other like terms
indicating relative positions to a given point or element are utilized to more
clearly describe
some elements of the embodiments of the invention. Commonly, these terms
relate to a
reference point with the surface from which drilling operations are initiated
being the top point
and the total depth of the well being the lowest point.
[0018] Figure 1 is a schematic drawing of an embodiment of an abrasive jet
cutting tool of the
present invention, generally denoted by the numeral 10. The cutting tool 10 is
positioned within
a tubular 12 disposed in a wellbore 14 to create a cut 34 in the tubular 12.
As will be described
in detail herein, the method and system of the present invention can provide
linear and non-linear
cuts in a tubular 12.
[0019] The cutting tool 10 of the present embodiment includes a positioning
module 16, a linear
actuator 18, a fluid pump 20, and a cutting unit 22. The fluid pump 20 further
comprises a fluid
chamber 21. In some embodiments, the fluid chamber 21 further comprises a
filter. In such
embodiments, well fluids are drawn into the fluid chamber 21 and filtered for
contaminants until
suitable for use in the cutting unit 22. In alternate embodiments of the fluid
chamber 21, where
the existing well fluids are not suitable for use in the cutting unit 22, the
fluid chamber 21
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comprises one or more fluid carriers to allow for the cutting fluid to be
carried to the cutting
depth from surface.
[00201 The cutting unit 22 of the cutting tool 10 further comprises a high
pressure pumping
system 24, an abrasive fluid feeder 26, and a rotary cutting head 27. The
rotary cutting head 27
comprises a nozzle 42 for discharging the cutting fluid. Movement of the
cutting head 27 is
provided by a linear actuator 10 and a rotary actuator 46 functionally
connected to the cutting
head 27.
[00211 The cutting tool 10 is connected to a conveyance means 28 via a head
30. In the
embodiment illustrated, the conveyance means 28 is shown as a wireline;
however, other
conveyance means including, without limitation, coiled tubing may be utilized.
The tool 10 may
further include an anchor 32 for securing the tool 10 within a tubular 12.
[00221 During completion or operation of the well, it may be desired or
necessary to cut a
tubular 12 in a region 36. For example, it may be desired to remove a portion
of a tubular 12
when it has become stuck in the wellbore 12 during completion or for plugging
and
abandonment operations. When a portion of a tubular 12 is to be removed, the
tool 10 may be
used to create a continuous, linear cut 34a (Figure 2) radially through the
tubular 12. In another
example, it may be desired to create an opening or window 38 (Figure 3A) in a
tubular 12 to
kick-off from the wellbore 14 or to provide a port for fluid ingress or
egress. The window 38, of
any geometric shape, may be formed by making a continuous non-linear cut (34b)
with the tool
10.
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[0023] To make a cut 34 in a tubular 12, the tool 10 is run into the wellbore
14 and the tubular
12 via a conveyance means 28 and positioned proximate the region 36 of
interest. The cutting
tool 10, and more specifically the cutting head 27, may be positioned
utilizing the positioning
module 16. The positioning module 16 may include various electronics,
including without
limitation, telemetry equipment and a casing collar locator. Upon positioning
the tool 10 in the
desired location, the anchor 32 may be actuated to secure the tool 10 within
and to the tubular 12.
It is desirable to secure the cutting tool 10 so that the tool 10 resists
movement in response to the
cutting operations facilitating a more accurate and continuous cut.
[0024] The linear actuator 18 provides movement of the cutting head 27 and the
nozzle 42
axially, as shown by the line "XX", relative to the tool 10 and the tubular
12. The axis "XX"
represents both the longitudinal axis of the tool 10 and of the tubular 12
proximate the region 36
of interest. The rotary actuator 46 facilitates rotary motion of the cutting
head 27, as indicated by
the arrow 48, about the longitudinal axis "XX." Plane "YY" extends
substantially perpendicular
to axis "XX."
[0025] As discussed above, in some embodiments of the present invention, a
fluid may be stored
and carried within the fluid chamber 21 and then mixed with an abrasive from
the feeder 26 to
form the abrasive cutting fluid 44. The cutting fluid 44 is discharged through
the nozzle 42 via
the high pressure pumping system 24 for cutting the tubular 12. In alternate
embodiments, the
abrasive cutting fluid 44 may be pre-mixed and carried by the tool 10. The
operation of the fluid
pump 20, cutting unit 22 and actuators 18, 46 may be controlled via signals
communicated by
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telemetry or through the conveyance means 28 to the positioning module 16. The
positioning
module, 16 including control electronics, is in functional connection with the
cutting unit 22.
[0026] Figure 2 is an illustration of a radial cut 34a created in a tubular 12
utilizing the cutting
tool 10. With reference to Figure 1, a method of creating a linear, radial cut
34a is described.
The cutting tool 10 is positioned within the tubular 12 with the cutting head
27 positioned within
the region 36 of interest. The anchor 32 is actuated to extend its arms 50 to
engage the tubular
12 and stabilize the tool 10. The cutting unit 22 is energized, mixing the
abrasive and fluid as
cutting fluid 44 which is discharged via the pumping system 24 to initiate a
cut 34a. The linear
actuator 18 is maintained in the static position and the rotary actuator 46 is
actuated to rotate the
cutting head 27 to create a linear radial cut 34a. As is readily recognized, a
linear, axial cut
(along the axis "XX") may also be made by maintaining the rotary actuator 18
in the static
position and activating the linear actuator 32 to move the cutting head 27
axially. A method for
completing cut 34a is illustrated in Figure 3B.
[0027] Figure 3A is an illustration of a non-linear cut 34b created in a
tubular 12 utilizing the
cutting tool 10 of Figure 1 to form a window 38. The window 38 may be formed
in any
geometric shape by forming a continuous, non-linear cut 34b. A non-linear cut
is made by
utilizing the linear and the rotary actuators 18, 46 in combination to move
the cutting head 27
along the desired path for the cut 34b.
[0028] Figure 3B is an exploded view of a cut finalization step 52 to create
and complete a
continuous cut 34. For example, in Figure 3A it is desired create a window 38
and then to
cleanly remove it from the tubular 12. This requires that the cut 34b be
continuous. In Figure 2,
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it is desired to remove the top portion of the tubular 12 from the wellbore
14; thus, it is necessary
to complete a continuous cut 34a.
[00291 The continuous cut 34 is illustrated by the dashed line in Figure 3B.
The cut 34 is started
at an initiation point 54 and proceeds in the direction of arrow 1. Desirably,
the cut 34 is
continued until it connects to the initiation point 54. However, due to
miscalculations or
movement of the tool 10, the cut 34 may not meet the initiation point 54
resulting in a non-
continuous cut. To avoid an incomplete cut, the cut 34 is continued in the
direction 2 to a
termination point 56. The termination point 56 is located along the cut 34
past the initiation point
54. At the termination point 56, the cutter head 27 is moved substantially
perpendicular, shown
by arrow 3, to the previous direction of movement shown by arrows 1 and 2. In
this manner, it is
ensured that a continuous cut 34 is completed.
[00301 From the foregoing detailed description of specific embodiments of the
invention, it
should be apparent that a system and method for creating linear and non-linear
cuts through
tubulars in a wellbore that is novel has been disclosed. Although specific
embodiments of the
invention have been disclosed herein in some detail, this has been done solely
for the purposes of
describing various features and aspects of the invention, and is not intended
to be limiting with
respect to the scope of the invention. It is contemplated that various
substitutions, alterations,
and/or modifications, including but not limited to those implementation
variations which may
have been suggested herein, may be made to the disclosed embodiments without
departing from
the spirit and scope of the invention as defined by the appended claims which
follow.
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