U.S. patent application number 10/008985 was filed with the patent office on 2002-06-13 for reaming tool with radially extending blades.
Invention is credited to Armell, Richard A., Armell, Stephen L..
Application Number | 20020070052 10/008985 |
Document ID | / |
Family ID | 9904685 |
Filed Date | 2002-06-13 |
United States Patent
Application |
20020070052 |
Kind Code |
A1 |
Armell, Richard A. ; et
al. |
June 13, 2002 |
Reaming tool with radially extending blades
Abstract
A downhole reaming tool is disclosed having radially extendible
cutting blades extended by hydraulic pressure directed into the
tool to force an inner tubular body having protrusions thereon with
tapered sides forward against the walls of mating recesses defined
in such radially extendible cutting blades to extend the
blades.
Inventors: |
Armell, Richard A.;
(Montrose, GB) ; Armell, Stephen L.; (Loyang
Crescent, SG) |
Correspondence
Address: |
William Nitkin
Suite 424
850 Boylston Street
Chestnut Hill
MA
02467
US
|
Family ID: |
9904685 |
Appl. No.: |
10/008985 |
Filed: |
December 6, 2001 |
Current U.S.
Class: |
175/273 ;
175/406 |
Current CPC
Class: |
E21B 10/322
20130101 |
Class at
Publication: |
175/273 ;
175/406 |
International
Class: |
E21B 007/28; E21B
010/32 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 7, 2000 |
GB |
0029939.6 |
Claims
I claim:
1. A reaming tool having a longitudinal axis, said tool comprising:
an inner tubular body; at least one protrusion disposed on said
inner tubular body, said protrusion having tapered sides and a
shape; at least one radially extendible cutting blade, said cutting
blade having at least one recess defined therein for receipt of
said protrusion, said recess having tapered walls and shape mating
with the shape of said protrusion; means to move said inner tubular
body forward; and means to retain said radially extendible cutting
blade from moving forward while allowing said cutting blade to move
radially outward forced by contact of said tapered protrusion
against a side of said recess defined in said radially extendible
cutting blade.
2. The reaming tool of claim 1 further including: a plurality of
cutting blades radially disposed around said inner tubular
body.
3. The reaming tool of claim 2 further including: at least two
protrusions disposed on said inner tubular body, each having a
tapered side; and at least two recesses defined in said cutting
blades for receipt of said protrusions in mating relationship
therewith.
4. The reaming tool of claim 2 further including: a plurality of
protrusions disposed on said inner tubular body, each having a
tapered side; and a plurality of mating recesses defined in said
cutting blades for receipt of said protrusions in mating
relationship therewith.
5. The reaming tool of claim 4 wherein said means to move said
inner tubular body comprises a mandrel adapted for receipt of
hydraulic pressure thereon, said mandrel engaged against said inner
tubular body, said reaming tool further including a spring for
returning said mandrel to an inactive position once said hydraulic
pressure has been reduced below the compression level of said
spring.
6. The reaming tool of claim 5 wherein each protrusion on said
inner tubular body is of a shape selected from the group consisting
of curved, pyramidically tapered and conically tapered shapes and
wherein the angle of tapering of the sides of the protrusion is
between 20 degrees and 60 degrees.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention resides in the field of reaming tools
for use in wells and the like and more particularly relates to a
downhole reaming tool having radially extendible reaming
members.
[0003] 2. History of the Prior Art
[0004] When drilling or working on bore holes for use, for example,
in oil or gas exploration, it is common to drill such bore holes in
a number of steps. First, a large surface hole is created and a
casing is installed to act as a lining in the bore hole. Often, the
next section of the bore is drilled using a smaller drill bit so
that the second section of the bore hole has a smaller diameter
than that of the first section. Subsequent sections of the bore
holes are drilled using drill bits having progressively smaller
diameters and lined with casings having similarly smaller
diameters. It is often desired to increase the diameter of a
section of the bore hole well below the surface. This operation is
conducted using a tool often referred to as an underreamer.
[0005] Underreaming tools commonly comprise one or more pairs of
cutting blades which are movable from a retracted position to an
expanded position. For example, GB Patent No. 2,320,270 describes a
tool in which a pair of blades is pivotally mounted on a tubular
body. The extension of the blades can be controlled by a piston
which is moved by an increase in fluid pressure in the tubular
body. However, the pivot system used in the above arrangement is
known to be unreliable as the degree of expansion of the blades is
not easy to control. In addition, the extended blades only provide
a short cutting region which is limited by the diameter of the
tool.
[0006] An alternative mechanism was suggested in U.S. Pat. No.
4,842,082 which discloses a tool comprising a slidably movable
ring. The slidably movable ring is urged against a second member by
a spring, and cooperating tapered edges cause the slidable member
to move in a radial direction. Thus, the diameter of the cutting
blades is increased without the use of a pivot.
[0007] However, the above system has a number of drawbacks.
Firstly, using a spring to provide the force to extend the cutting
blades results in problems with control of the device. The spring
provides a force that depends on the displacement from an
equilibrium position and the spring constant. Thus, at a particular
extension, the outward force has a particular value, which cannot
be increased beyond the limitations of the spring. As a result,
obstructions in the well may prevent extension of the blades.
Furthermore, the properties of the spring will deteriorate over
long periods of use, thereby decreasing the available force.
[0008] Secondly, in the device of U.S. Pat. No. 4,842,082, the
cutting blades are prone to "cocking" which can occur when an
unevenly tapered surface or an obstructing particle on one of the
blade's edges can cause the sliding ring or cutting blade to stick,
preventing further movement at the stuck edge. The other
free-sliding edge will ride up its associated taper to a point
where its radial extension is greater than that of the stuck edge,
resulting in an angled cutting blade. In use, a cutting blade that
is not parallel with the work string may cause unevenly cut well
bores and/or helical grooves in the well.
SUMMARY OF THE INVENTION
[0009] It is an object of the present invention to provide a
radially expandable downhole tool that includes an inner tubular
body having at least one protrusion on an outer surface thereof,
and a reaming member mounted on the inner tubular body having at
least one recess on an inner surface thereof for receiving said
protrusion(s), said recess(es) and said protrusion(s) being shaped
such that relative axial motion between the reaming member and the
tubular body causes a movement of the reaming member in a radial
direction, such axial movement being actuated by hydraulic urging
means.
[0010] In a preferred embodiment, the reaming member includes a
reaming surface. The reaming surface can include a plurality of
cutting blades spaced around the circumference of the inner tubular
body. Each cutting blade can extend substantially the length of the
inner tubular body and run parallel to the long axis of the inner
tubular body. In a preferred embodiment the reaming member has a
plurality of recesses, and the inner tubular body has a like number
of protrusions. In one embodiment there can be two recesses and two
protrusions. In a preferred embodiment the protrusions and recesses
have mating sides which sides can be curved or tapered sides such
as conically tapered or pyramidically tapered. The protrusions and
recesses can be of the same length. The hydraulic urging means can
be a piston actuable on the inner tubular body and operated by
hydraulic fluid. The fluid can be pumped through a work string
attached to the tool. Thus by varying the pump pressure of the
hydraulic fluid the radial movement of the reaming member can be
controlled.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1A illustrates a longitudinal cross-sectional view of
the tool of this invention in an open position.
[0012] FIG. 1B illustrates a longitudinal cross-sectional view of
the tool of FIG. 1 in an closed position.
[0013] FIG. 2a illustrates a cross-sectional view of a portion of
the tool of FIG. 1A showing the interaction of the reaming member
and the inner tubular body wherein the reaming member is
extended.
[0014] FIG. 2b illustrates a view of a portion of the tool of FIGS.
1 and 1B showing the interaction of the reaming member and the
inner tubular body wherein the reaming member is retracted.
[0015] FIG. 2c illustrates a cross-sectional view showing the inner
tubular body and the reaming member in a retracted mode.
[0016] FIG. 2d illustrates a cross-sectional view showing the inner
tubular body and the reaming member in an extended mode.
[0017] FIG. 3a illustrates a longitudinal view of a section showing
the interaction of the reaming member and the inner tubular body in
an alternate arrangement with the blade radially extended.
[0018] FIG. 3b illustrates a longitudinal view of a section showing
the interaction of the reaming member and the inner tubular body in
the alternate arrangement of FIG. 3 a with the blade retracted.
DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0019] FIGS. 1A and 1B illustrate a longitudinal cross-sectional
view of tool 100 of this invention which tool includes reaming
member 120 having a plurality of cutting blades such as cutting
blades 121 and 122 running parallel to the longitudinal axis 175 of
the tool and positioned around the circumference of the tool.
Reaming member 120 is located on inner tubular body 130 which, in
this embodiment, has a plurality of protrusions 131A, 131B, 132A
and 132B. These protrusions are received by mating recesses 121A,
121B, 132A and 132B in cutting blades 121 and 122. Other blades can
be provided such as seen in FIGS. 2c and 2d. The tool has an outer
tubular body 140 and hydraulic urging means in the form of mandrel
150. Mandrel 150 is movable within a cylinder formed by outer
tubular body 140 and reaming member 120. Spring 170 is present
between ledge 142 of outer tubular body 140 and head 152 of mandrel
150. The spring can be a compression spring, producing a force
acting against downward movement of the mandrel. Mandrel 150 is in
the form of a long tube consisting of upper section 150A and lower
section 150B. The wall of the upper section has a greater thickness
than that of the lower section, with a distinct step 151 in between
the two sections. This step abuts edge 133 of inner tubular body
130 in this embodiment. The outer tubular body has a number of
outlets 144 for the circulation of fluid. Additional outlets can be
provided, positioned so that circulating fluid assists in the
reaming action by cleaning debris from the cutting blades and/or
lifting cuttings from the hole.
[0020] The tool is also fitted with a nose cutter 180. Nose cutter
180 can be a spade cutter with variable diameter as is conventional
in the art.
[0021] FIGS. 2a-2d illustrate more details of the inner tubular
body and reaming member. The edges of the mating protrusions and
recesses are tapered to allow, for example, cutting blade 122 and
inner tubular body 130 to slide against one another, as seen in
FIGS. 2a and 2b. FIGS. 2c and 2d illustrate cross-sections of the
inner tubular body and reaming member showing cutting blades 121,
122, 123 and 124 which are shown retracted in FIG. 2c and extended
in FIG. 2d.
[0022] In use, a work string, which is not shown, is attached to
the tool and the tool is lowered into a well bore. The cutting
blades are fully retracted, as seen in FIG. 1B, by virtue of spring
170 which urges mandrel 150 in an upward direction. Cutting blades
121 and 122 rest on inner tubular body 130 with protrusions 131A,
131B, 132A and 132B resting respectively inside recesses 121A,
121B, 122a and 122b which recesses are best seen in FIG. 1A. Thus
the cutting blades shown in FIGS. 1B and 2b are in their retracted
positions.
[0023] When the tool is in the desired region of the well bore,
fluid is pumped into cavity 190 above mandrel head 152, increasing
the fluid pressure in cavity 190 and the downward force on the
mandrel head 152. This force is countered by spring 170 on the
underside of mandrel head 152. However, when the compressive force
of the fluid exceeds that of the spring force and the external
inward force from the well bore, spring 170 is compressed. Mandrel
150, via step 151, pushes inner tubular body 130 in a downward
direction. Cutting blades such as cutting blades 121 and 122 are
attached to the tool so as only to have limited axial travel.
Cutting blades such as cutting blades 121 and 122 are prevented
from moving downward with inner tubular body 130, so the resulting
force on cutting blades 121 and 122 from the downwardly moving
tapered edges 161, 162, 163 and 164 of the inner tubular body
causes cutting blades such as cutting blades 121 and 122 to be
forced to ride up tapered edges 161, 162, 163 and 164 and be moved
into a radially extended position, as shown in FIGS. 1A and 2a.
[0024] Once the cutting blades are radially extended, the tool can
be rotated by a downhole motor, or by rotation of the whole work
string for the reaming of the bore hole walls. The tool can be
raised or lowered on the work string if required. The tool can be
used, for example, to ream an inside surface of a bore hole or, for
example, to remove scale, cement, barium or paraffin.
[0025] In order to retract the blades, the hydraulic pressure in
cavity 190 is lowered by reducing the pump pressure. Mandrel 150
moves in an upward direction due to the force of spring 170, and
inner tubular body 130 moves upwards by the force of spring 170,
allowing the cutting blades such as cutting blades 121 and 122 to
shift inward from outside pressure to their retracted
positions.
[0026] The tool of this invention can be constructed in such a way
that inner tubular body 130 is fixed to mandrel 150 so that the two
move up and down together. Alternatively, when mandrel 150 is
raised, inner tubular body 130 can return to its retracted position
pushed by the cutting blades from external forces from the well
bore. Thus pressure in the bore hole produces a force on the
cutting blades which, via the tapered edges, forces inner tubular
body 130 in an upward direction. If required, additional springs or
biasing means can be provided to urge the cutting blades in an
inward direction to ensure that they remain retracted when
desired.
[0027] The edges of the protrusions of inner tubular body 130 and
recesses in the blades must be shaped to allow smooth relative
movement of inner tubular body 130 and reaming member 120. Any
suitable curve can be used, but in one preferred embodiment the
edges are tapered. The edges can be curved, pyramidically tapered
or conically tapered. The angle of tapering chose depends on a
variety of factors, including degree of travel (axially and
radially), pressure used, required cutting force and friction
present between the inner tubular body and the cutting blades. The
angle of the blade taper can be in the range of 20 degrees to 60
degrees, and is typically 36.5 degrees.
[0028] Although the cutting blades are shown to have two recesses
each, the invention is not limited to this arrangement or number of
recesses. However, two or more recesses are preferable, because
this arrangement provides a smoother movement and greatly decreases
the likelihood of the tapered edges of the protrusions sticking,
and the blade cocking as a result.
[0029] Although the cutting blades are shown as being straight and
parallel to the longitudinal axis of the tool, in an alternate
embodiment they can be profiled to clean no go profiles, valve
profiles, sliding sleeves, nipples, seal bores or shifting
profiles, as required. Typically the tool of this invention can be
used for polishing rough edges in bore holes and for setting
packers, casings or patches.
[0030] The edges of the cutting blades can be provided with a
hardened facing, such as tungsten carbide. The tool can be used in
both vertical and horizontal well bores.
[0031] FIG. 3a and 3b shows the cutting blade 122 and inner tubular
body 130 in an alternate embodiment. This embodiment is similar to
the first embodiment except that the blades have protrusions and
the inner tubular body has recesses. FIG. 3b shows inner tubular
body 130 with the protrusions of cutting blades 121 and 122 resting
within recesses in inner tubular body 130.
[0032] The tool can be run on coiled tubing, a work string,
snubbing units or drilling rigs. When coiled tubing is used, the
tool should be installed below the motor.
[0033] The present invention allows a greater degree of control
over the extension and retraction of the cutting blades compared to
tools of the prior art since the cutting blades' movement is
controlled by fluid pressure. The pressure can be increased to
exceed the combined effect of the spring bias and the external
force on the cutting blades so that the blades can be radially
extended more reliably. The blades can be retracted or extended as
many times as needed by cycling the pump pressure.
[0034] Another important advantage of the present invention is that
the blades can be fully retracted. Full retraction allows the tool
to pass through seal bores of the completion components. In some
embodiments the mandrel can engage the reaming member, forcing it
to move over the inner tubular body, such body being fixed relative
to the rest of the tool.
[0035] Although the present invention has been described with
reference to particular embodiments, it will be apparent to those
skilled in the art that variations and modifications can be
substituted therefor without departing from the principles and
spirit of the invention.
* * * * *