U.S. patent application number 11/374904 was filed with the patent office on 2006-09-21 for multi-function downhole tool.
This patent application is currently assigned to Stable Services Limited. Invention is credited to Arthur Stewart.
Application Number | 20060207796 11/374904 |
Document ID | / |
Family ID | 36570553 |
Filed Date | 2006-09-21 |
United States Patent
Application |
20060207796 |
Kind Code |
A1 |
Stewart; Arthur |
September 21, 2006 |
Multi-function downhole tool
Abstract
A multi-function downhole apparatus is described which comprises
a tubular main body having at least one recess formed in its outer
surface. The recess is adapted to receive any of a set of
interchangeable tool elements, which include stabiliser blades of
different radial sizes, cleaning elements, roller reaming tool
elements, a hole opener tool element, and a drilling casing shoe
element. In particular, the apparatus allows drilling operations
and wellbore cleaning operations to be carried out using the same
tool body.
Inventors: |
Stewart; Arthur; (Potterton,
GB) |
Correspondence
Address: |
EDWARDS & ANGELL, LLP
P.O. BOX 55874
BOSTON
MA
02205
US
|
Assignee: |
Stable Services Limited
South Manse, Panmure Gardens
Potterton
GB
8UG
|
Family ID: |
36570553 |
Appl. No.: |
11/374904 |
Filed: |
March 14, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60661385 |
Mar 14, 2005 |
|
|
|
Current U.S.
Class: |
175/57 ;
175/325.1 |
Current CPC
Class: |
E21B 21/00 20130101;
E21B 37/02 20130101; E21B 17/10 20130101; E21B 10/26 20130101; E21B
17/00 20130101 |
Class at
Publication: |
175/057 ;
175/325.1 |
International
Class: |
E21B 17/10 20060101
E21B017/10 |
Claims
1. A multi-function downhole apparatus comprising: a tubular main
body having at least one recess formed in an outer surface of the
body, the recess adapted to receive each of a set of
interchangeable tool elements, wherein the set of interchangeable
tool elements comprises any two of a first stabiliser blade, a
second stabiliser blade, a cleaning element, a roller reaming tool
element, a hole opener tool element, and a drilling casing shoe
element.
2. The apparatus as claimed in claim 1, wherein the recess is
adapted to receive a first stabiliser blade of a first radial
dimension to provide stabilising apparatus for use in a wellbore of
a first dimension, and a second stabiliser blade of a second radial
dimension to provide stabilising apparatus for use in a wellbore of
a second dimension.
3. The apparatus as claimed in claim 2, wherein the recess is
adapted to receive a first stabiliser blade to provide stabilising
apparatus for a first wellbore dimension, and a cleaning element to
provide a wellbore clean-up apparatus.
4. The apparatus as claimed in claim 1, wherein the body is
provided with a bore aligned on an attachment axis inclined to a
radial axis of the tubular body.
5. The apparatus as claimed in claim 1, further comprising a first
set of recesses circumferentially distributed around the body.
6. The apparatus as claimed in claim 5, further comprising a second
set of recesses circumferentially distributed around the body in a
location longitudinally displaced from the first set of
recesses.
7. The apparatus as claimed in claim 6, wherein the second set of
recesses is rotationally offset with respect to the first set of
recesses.
8. The apparatus as claimed in claim 1, wherein the tubular body of
is provided with a plurality of elongate ribs upstanding from an
outer surface of the main body and extending at least part way
along a length thereof.
9. The apparatus as claimed in claim 8, wherein the recess is
formed in an outer surface of the rib.
10. The apparatus as claimed in claim 9, wherein adjacent pairs of
ribs define a flow channel therebetween for flow of a downhole
medium along the body.
11. The apparatus as claimed in claim 10, wherein the tubular body
further comprises at least one flow guide located adjacent an end
of the channel, the flow guide and the channel together defining a
flow path for flow of a downhole medium along the body.
12. The apparatus as claimed in claim 8, wherein the ribs are
aligned substantially parallel to a longitudinal axis of the
body.
13. The apparatus as claimed in claim 8, wherein the ribs are
shaped such that at least one dimension of each channel is
non-uniform.
14. A downhole apparatus comprising: a tubular main body; at least
one longitudinal recess formed in an outer surface of the body; a
removable tool element received in the recess and upstanding from
the outer surface of the main body; wherein the removable tool
element has an outer surface comprising an upper portion and a side
wall portion, and the removable tool element is attached to the
main body via an attachment mechanism extending from the side wall
portion, through the removable tool element, and into the main
body.
15. The apparatus as claimed in claim 14, wherein the attachment
mechanism comprises a bore aligned on an attachment axis inclined
to a radial axis of the tubular body.
16. A kit of parts for the assembly of a downhole tool, the kit of
parts comprising: a tubular main body having at least one recess
formed in an outer surface of the body; and a set of
interchangeable tool elements comprising any two of a first
stabiliser blade, a second stabiliser blade, a cleaning element, a
magnetic debris collector, a roller reaming tool element, a hole
opener tool element, a drilling casing shoe element; wherein the
recess is adapted to receive one of the set of interchangeable tool
elements, to provide a downhole tool having a first operating
configuration, and is adapted to receive another of the set of
interchangeable tool elements, to provide a downhole tool having a
second operating configuration.
17. The kit of parts as claimed in claim 16, wherein the first
operating configuration is for a drilling operation, and the second
operating configuration is for a wellbore clean up operation.
18. A method of configuring a multi-function downhole apparatus,
the method comprising the steps of: Removing a first tool element
from a recess in a tubular body; Removably attaching a second tool
element, different from the first, to the recess in the tubular
body; Wherein the first and second tool elements are any two
selected from a first stabiliser blade, a second stabiliser blade,
a cleaning element, a magnetic debris collector, a roller reaming
tool element, a hole opener tool element, a drilling casing shoe
element.
19. A method of configuring a downhole apparatus, the method
comprising the steps of: Removing a first tool element from a
recess in a tubular body; Removably attaching a second tool element
to the recess in the tubular body; Wherein the first tool element
is a stabiliser blade having a first radial dimension for running
in a wellbore of first inner diameter, and the second tool element
is a stabiliser blade having a second radial dimension, different
from the first, for running in a wellbore of second inner diameter.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Patent
Application No. 60/661,385, filed Mar. 14, 2005, which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to downhole tools used in
wellbores, and, in particular, to downhole tools used in rotary
operations.
[0004] 2. Background of the Related Art
[0005] A number of different types of downhole tools and equipment
are used in the oil and gas exploration and production industry
during the drilling of a wellbore, lining of the drilled bore with
a metal casing/liner, and in the subsequent completion of the well
to gain access to subterranean hydrocarbon bearing rock
formations.
[0006] These tools and equipment include, for example, drill
strings used in the drilling of a wellbore; stabilisers and
centralisers used for centralising equipment in a borehole or
downhole tubing; reamers and other cutting tools used for reaming a
drilled borehole wall; and cleaning tools used for cleaning
downhole tubing preparatory to completion of a well or in an
intervention procedure.
[0007] In the oil and gas exploration industry, numerous wellbores
are drilled and maintained with the assistance of different types
of downhole tools. Such tools are mounted on or incorporated into a
string for use in various well bore operations. Such a string could
for example be a drill string where it is be usual for the string
to be rotated within the well bore. Another tubular string commonly
encountered in such operations is a casing string.
[0008] In drilling operations, bottomhole assemblies are provided
toward the downhole end of the string and are typically provided
with stabiliser tools. These stabilisers provide a stand-off of the
string from the wellbore walls as their outer surface is juxtaposed
the wellbore walls. Stabilisers help to keep the drill pipe or
heavyweight drill pipe and drill collar from the well bore wall
reducing friction, maintain the drill bit in the correct position
within the wellbore, and thus help to maintain torque on the drill
bit.
[0009] Known drill string stabilisers are typically cylindrical
tubular elements which are fitted around the drill pipe or provided
integrally with the pipe, and often include grooves to allow fluid
to pass relatively unrestricted upwards through the well borehole.
Some known stabilisers have helical groove channels extending
around the body of the pipe.
[0010] In a similar fashion, drill collars of a bottomhole assembly
may carry integral stabiliser arrangements of a similar structure,
or a stabiliser arrangement of this type may be provided above the
drill bit, for a similar purpose of helping to remove fluid and
debris away from the drill bit or a drill shoe of the assembly and
along the wellbore annulus to surface.
[0011] Grooved stabiliser elements are also used during reaming,
which is either a secondary drilling process for re-entering an
existing wellbore, for example for enlarging the wellbore diameter,
or for ensuring a drilled borehole is of a desired diameter.
[0012] Cleaning tools are also often applied at various points on
the string and are provided with a scouring or scraping outer
surface for removing residue from the insides of the wellbore walls
or inside walls of casing.
[0013] Strings run in casing are typically equipped with protecting
sleeves. Further, casing strings are provided with tubular
centralisers that keep the casing central in the wellbore with an
annular space between the outer surface of the casing and the
wellbore walls.
[0014] The downhole tools and various string elements must be
constructed such that they can withstand the forces that they may
be subjected in a wellbore whilst performing their specific
functions within the string. Ideally, the elements are able to
function while other wellbore procedures are carried out
simultaneously, thus maximising efficiency. During operation of a
string in a wellbore, fluid is typically pumped down through the
centre of the string at pressure causing the fluid to return back
up through the outer wellbore annulus flushing out cuttings and
debris. It is therefore important for a stabiliser tool used during
drilling to accommodate the passage of drilling fluid from the
rotating drill bit through the annulus between the wellbore wall
and the string. Similar performance is required of cleaning tools,
centralisers and other downhole tools.
[0015] Typically, in drilling and cleaning operations, a particular
tool is designed and configured for a specific task in a wellbore.
Indeed, for drilling, stabilising, centralising and clean-up
operations, the tools may be of a specific outer diameter
corresponding to the inner diameter of the bore or casing in which
they are run. When the wellbore has sections at depths of
decreasing inner diameter, it may be necessary to remove the tool
and replace with a different tool of appropriate dimensions.
[0016] Such downhole tools are often incorporated as individual
sections into a string. Changing out tools that have become worn or
introducing new tools to the string to deal with unexpected
problems can therefore result in a lengthy and costly operation. It
is desirable to be able to expeditiously react and replace and
introduce tools as required in the field.
[0017] Various proposals for downhole tools have been documented
that address some of the above issues. U.S. Pat. No. 4,190,124
(Taylor) provides details of a stabiliser with blades that are
removable. The blades fix into longitudinal slots provided on
planar components of the stabiliser main body. The planar
components are surfaces extending longitudinally and which are
effectively ridges with corresponding low relief valley channels
formed in between and allowing fluid to flow past.
[0018] International Patent Publication Number WO 91/05936
(Weatherford) discloses a centraliser, stabiliser, or pipe
protector having a fluted tubular cylindrical outer surface that
directs and channels fluid flow upwards through the wellbore. The
channels may create a helical path for the fluid. Protruding ribs
create an annular space between a string and the wellbore wall and
enhance turbulence of the fluid and material flowing past the
exterior surface of the device.
[0019] Further proposed systems include a downhole tool for
cleaning operations having detachable cleaning pads. These are
fastened in place with a nut and bolt. The purpose is to be able to
quickly replace worn brushes should it be necessary during
operations. The cleaning pads may be equipped with brushes or
scrapers.
[0020] Although prior art systems have addressed some important
issues, problems persist with current equipment causing much
downtime during drilling operations. One particular such problem
during rotary drilling is differential sticking of the pipe to the
wellbore wall, which is particularly common when drilling through
clay rich formations and when well pressure is greater than
formation pressures. Further, such formations cause `balling`,
which is the effect of solids such as clays sticking to various
tool components due to pressure effects. These effects prevent the
tools from operating properly and may drive the drill string to a
halt.
SUMMARY OF THE INVENTION
[0021] It is therefore desirable to provide a downhole apparatus
that obviates or at least mitigates some of the drawbacks of
associated with prior art downhole tools and methods.
[0022] It is amongst the aims and objects of the invention to
provide a downhole apparatus capable of providing a body upon which
a variety of tool assemblies can be configured.
[0023] According to a first aspect of the invention, there is
provided multi-function downhole apparatus comprising: a tubular
main body;
[0024] at least one recess formed in an outer surface of the body,
the recess adapted to receive each of a set of interchangeable tool
elements, wherein the set of interchangeable tool elements
comprises any two of a stabiliser blade, a cleaning element, and a
roller reaming tool element.
[0025] In this context, the term cleaning element should be
construed broadly and includes elements, components or assemblies
providing a cleaning, scraping, scouring, or brushing function in a
wellbore. This includes debris or junk collection elements, and
magnetic components configured for junk or debris collection.
[0026] According to a second aspect of the invention, there is
provided a method of configuring a multi-function downhole
apparatus, the method comprising the steps of: [0027] Removing a
first tool element from a recess in a tubular body; [0028]
Removably attaching a second tool element, different from the
first, to the recess in the tubular body; Wherein the first and
second tool elements are any two selected from a stabiliser blade,
a cleaning element, and a roller reaming tool element.
[0029] The method allows the same tubular body to be configured as
a cleaning tool, a stabiliser tool, or a roller reaming tool.
[0030] The tool may comprise a first set of recesses
circumferentially distributed around the body.
[0031] In one embodiment, the tool comprises a second set of
recesses circumferentially distributed around the body in a
location longitudinally displaced from a first set of recesses on
the body.
[0032] Preferably, the second set of recesses is rotationally
offset with respect to the first set of recesses. In this way, the
first and second set of recesses together provide an increased
circumferential coverage of the tool elements when the tool is
being run in the wellbore.
[0033] In one embodiment, the tool comprises a magnetic tool
element. The magnetic tool element may be received in the recess.
The radial dimension of the magnetic tool element may be less than
the depth of the recess such that the outer surface of the magnetic
tool insert is inset with respect to the outer dimension of the
apparatus. In this way, the apparatus provides a pocket for the
collection of debris, junk and cuttings from the wellbore.
[0034] According to a third aspect of the invention, there is
provided a method of configuring a downhole apparatus, the method
comprising the steps of: [0035] Removing a first tool element from
a recess in a tubular body; [0036] Removably attaching a second
tool element to the recess in the tubular body; Wherein the first
tool element is a stabiliser blade having a first radial dimension
for running in a wellbore of first inner diameter, and the second
tool element is a stabiliser blade having a second radial
dimension, different from the first, for running in a wellbore of
second inner diameter.
[0037] The method allows the same tubular body to be used as a
stabiliser tool in wellbores, casings and linings of different
inner diameter.
[0038] According to a fourth aspect of the invention there is
provided downhole apparatus comprising:
a tubular main body;
at least one recess formed in an outer surface of the body, the
recess adapted to receive a removable tool element;
wherein the body is provided with at least one bore for coupling a
removable tool element, and the bore is aligned on an attachment
axis inclined with respect to a radial axis of the body.
[0039] Preferably, the recess is formed to extend radially of the
body. More preferably, the apparatus is adapted to receive a
removable tool element extending radially of the body.
[0040] By inclining the attachment axis the need to provide a screw
or bolt extending the entire depth of the removable tool element is
avoided. In addition, the attachment axis can be aligned such that
forces encountered during wellbore operations have an increased
axial component.
[0041] According to a fifth aspect of the invention there is
provided a downhole assembly comprising:
a tubular main body;
at least one recess formed in an outer surface of the body;
a plurality of interchangeable tool elements comprising of any two
of selected from group of: a stabiliser blade of a first radial
dimension, a stabiliser blade of a second radial dimension, a
cleaning element, and a roller reaming tool element;
wherein the recess is adapted to receive the each of the plurality
of interchangeable tool elements during a different mode of
operation.
[0042] According to a sixth aspect of the invention there is
provided a downhole assembly comprising:
a tubular main body;
at least one recess formed in an outer surface of the body;
a removable tool element;
wherein the body is provided with at least one bore for coupling
the removable tool element to the body, and the bore is aligned on
an attachment axis inclined with respect to a radial axis of the
body.
[0043] According to a seventh aspect of the invention there is
provided a downhole assembly comprising:
a tubular main body;
at least one longitudinal recess formed in an outer surface of the
body;
a removable tool element received in the recess and upstanding from
the outer surface of the main body;
[0044] wherein the removable tool element has an outer surface
comprising an upper portion and a side wall portion, and the
removable tool element is attached to the main body via a bore
extending from the side wall portion, through the removable tool
element, and into the main body.
[0045] Preferably, the bore is aligned on an attachment axis
inclined to a radial axis of the tubular body.
[0046] Preferably, the tubular body of any of the first to seventh
aspects of the invention is provided with a plurality of elongate
ribs upstanding from an outer surface of the main body and
extending at least part way along a length thereof. More
preferably, the recess is formed in an outer surface of the
rib.
[0047] The recess may be aligned with the longitudinal axis of the
tubular body.
[0048] Preferably also, adjacent pairs of ribs defining a flow
channel therebetween for flow of a downhole medium along the body.
The ribs may be aligned substantially parallel to a longitudinal
axis of the body. Advantageously, the ribs are shaped such that at
least one dimension of each channel is non-uniform.
[0049] The tubular body may further comprise at least one flow
guide located adjacent an end of the channel, the flow guide and
the channel together defining a flow path for flow of a downhole
medium along the body.
[0050] According to an eighth aspect of the invention, there is
provided a downhole tool comprising: a tubular main body having at
least one recess formed in an outer surface of the body, the recess
adapted to receive, when the apparatus is in a first configuration,
a stabiliser blade of a first radial dimension, and is adapted to
receive, when the apparatus is in a second configuration, a
stabiliser blade of a second radial dimension.
[0051] According to a ninth aspect of the invention there is
provided downhole apparatus comprising:
a tubular main body;
a plurality of elongate ribs upstanding from an outer surface of
the main body and extending at least part way along a length
thereof, adjacent pairs of ribs defining a flow channel
therebetween for flow of a downhole medium along the body;
wherein at least one rib is provided with a longitudinal recess
formed in an outer surface of the body, the recess adapted to
receive a removable tool element.
[0052] Preferably, the ribs are aligned substantially parallel to a
longitudinal axis of the body. More preferably, the ribs are shaped
such that at least one dimension of each channel is
non-uniform.
[0053] According to a tenth aspect of the invention, there is
provided a multi-function downhole apparatus comprising: a tubular
main body having at least one recess formed in an outer surface of
the body, the recess adapted to receive, when the apparatus is in a
drilling configuration, a first interchangeable tool element for
use in a drilling operation, and is adapted to receive, when the
apparatus is in a wellbore clean-up configuration, a second
interchangeable tool element for use in a wellbore clean up
operation.
[0054] It will be appreciated that the apparatus of all aspects of
the invention may be provided as an integral part of the tool or
tubing string, or as a separate component adapted to be coupled to
tubing, a tool string or sections of a tubing string such as a
length of casing. In particular, the apparatus may be formed as an
integral part of a tool string component, and may indeed form an
integral part of a drill pipe section.
BRIEF DESCRIPTION OF THE DRAWINGS
[0055] There will now be described, by way of example only,
embodiments of the present invention with reference to the
following drawings, of which:
[0056] FIG. 1A is a perspective view of apparatus in accordance
with a first embodiment of the invention;
[0057] FIGS. 1B and 1C are respectively side and plan views of the
apparatus of FIG. 1A;
[0058] FIG. 2A is a perspective, partially exploded view of a
stabiliser assembly consisting of the apparatus of FIG. 1 and
removable stabiliser blades;
[0059] FIGS. 2B and 2C are respectively side and plan views of the
assembly of FIG. 2A;
[0060] FIG. 3 is a perspective view of a cleaning assembly
consisting of the apparatus of FIG. 1 and removable cleaning
brushes;
[0061] FIG. 4 is a perspective view of a cleaning assembly
consisting of the apparatus of FIG. 1 and removable brush
scrapers;
[0062] FIG. 5 is a perspective view of an assembly consisting of
the apparatus of FIG. 1 and flush tool elements;
[0063] FIG. 6 is plan view of a recess of the apparatus of FIG.
1;
[0064] FIG. 7 is a cross-sectional view of an embodiment of the
invention showing recess profile and an attachment arrangement for
removable tool elements;
[0065] FIG. 8A is a perspective view of a further embodiment of the
invention having a set of recesses run in tandem;
[0066] FIG. 8B is a circumferential detail of a further embodiment
of the invention; and
[0067] FIG. 9 is a perspective view of a further embodiment of the
invention, configured as a hole opening tool.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0068] The present invention overcomes many of the prior art
problems associated with downhole apparatus. The advantages, and
other features of the invention disclosed herein, will become more
readily apparent to those having ordinary skill in the art from the
following detailed description of certain preferred embodiments
taken in conjunction with the drawings which set forth
representative embodiments of the present.
[0069] Reference is made firstly to FIGS. 1A, 1B and 1C, in which
downhole apparatus in accordance with a first embodiment of the
invention is shown, generally depicted at 10. As will be described
in more detail below, the downhole apparatus 10 may take the form
of one of a number of different types of downhole tools or
equipment. However, in general terms, the downhole apparatus 10
comprises a tubular main body 12; at least one flow channel 14
extending part-way along a length of the body 12 and a plurality of
raised portions or ribs 15 formed on the body 12. The ribs 15 are
shaped such that a dimension of the channel 14 (in this case,
width) is non-uniform. Flow guides 16 located adjacent to an end 18
of the channel 14, the flow guide 16 and the channel 14 together
defining a flow path for flow of a downhole medium along the body
12.
[0070] The apparatus 10 serves for promoting improved fluid flow
along an annulus defined between the body 12 and the wall of a well
borehole or of a tubing in which the apparatus is located. It will
therefore be understood that the apparatus 10 may be located in
open hole, that is within a drilled borehole of an oil or gas well;
within tubing previously located in a borehole such as a casing or
liner; or indeed within other tubing such as a tool string. The
apparatus 10 therefore has a wide range of potential uses in the
downhole environment.
[0071] The apparatus 10 is configured to as a tool for connection
to, or incorporation into, a string of tubular members employed in
wellbores. The body 12 of the apparatus 10 can be located in a
wellbore with its longitudinal axis aligned with the longitudinal
axis of the wellbore.
[0072] The ribs 15 are arranged to define a specific flow path such
that a channel is formed between the edges of the pads 15. The
channel has varying width due to the curvature of the edges of the
pads 15. The flow guides 16 may be provided with cutting edges 17A,
17B for disturbing the flow or breaking up particles and material
such as debris and cuttings that may be present in the borehole
fluid flow.
[0073] The ribs 15 are distributed circumferentially around the
tubular body 12 with their longitudinal axes aligned with the
longitudinal axis of the tubular body 12. In this embodiment three
ribs are distributed with equal spacing around the circumference of
the tubular body 12. The spacing and longitudinal dimension of the
ribs 16 is sufficient for imparting a directional effect on fluid
flowing past.
[0074] Each rib 16 is provided with longitudinally aligned recesses
11 into which different tool elements may be received and coupled
to the tubular body 12. The recesses 11 comprise a substantially
rectangular milled recess formed in the pad surfaces 19 of the ribs
15. In other embodiments the recesses 11 may have a different
shape. The recesses are dimensioned such that a tool element
located into the recess fits snugly with minimal relative motion
between the tool element and the juxtaposing interior side wall
surfaces of the recesses 11.
[0075] The ribs are shaped so that the basic tubular body provides
the aforementioned benefits in affecting flow of fluid and
cuttings, whilst providing an appropriate surface area for recesses
accommodating a plurality of interchangeable tool elements. The
recesses are designed to receive a plurality of different tool
elements having different functions and/or different dimensions to
permit the same tool body to be used in a number of different
wellbore operations. In this fashion, the apparatus 10 provides the
basis for a variety of tool assemblies including stabilising,
reaming and cleaning tools.
[0076] FIGS. 2A to 2C show the apparatus of FIG. 1 configured as a
stabiliser assembly, for use, for example, on heavyweight drill
pipe.
[0077] The assembly, generally depicted at 100, consists of the
apparatus 10 and a plurality of removable tool elements, which in
this example are stabiliser blades 102. The blades 102 are
dimensioned to fit exactly within the longitudinal recesses 11.
Attachment means are provided for removable attachment of the
blades 102 to the apparatus 10.
[0078] The blades 102 are formed to a specific (radial) depth to
provide stand-off between the inside wall of a wellbore and the
tubular member 3. The depth, and thus the outer diameter of the
assembly, is chosen according to the inner diameter of the borehole
or casing in which the string is being run, in order to provide a
snug fit. It will be appreciated that a variety of depths of
stabiliser blades can be made available at the surface to allow the
basic apparatus 10 to be configured for a range of different
borehole diameters.
[0079] FIG. 3 shows the apparatus 10 configured as a cleaning tool,
for use, for example, in cleaning the inner surface of casing in a
wellbore. The assembly, generally depicted at 110 consists of the
apparatus 10 and a plurality of removable tool elements, which in
this example are wire brush assemblies 112. The brush assemblies
112 consist of brush housings 114 dimensioned to fit exactly within
the longitudinal recesses 11 and an arrangement of wire bristles
116 on the exterior surface of the brush assembly. Attachment means
are provided for removable attachment of the brush assemblies 112
to the apparatus 10.
[0080] It will be understood that a variety of depths of brush
assemblies and bristle arrangements can be made available at the
surface to allow the basic apparatus 10 to be configured for a
range of different borehole diameters.
[0081] FIG. 4 shows the apparatus 10 configured as part of a
scraping tool, for use, for example, in scraping the inner surface
of casing in a wellbore. In this embodiment, the assembly,
generally depicted at 120 consists of the apparatus 10 and a
plurality of removable tool elements, which in this example are
brush scraper assemblies 122. The brush assemblies 122 consist of
housings 124 dimensioned to fit exactly within the longitudinal
recesses 11 and an arrangement of scraping bristles 126 on the
exterior surface of the scraper assembly. Attachment means are
provided for removable attachment of the brush assemblies 122 to
the apparatus 10.
[0082] The arrangement of FIG. 4 is similar to the arrangement
shown in FIG. 3, although the depth of the housings is selected to
be substantially flush with the ribs 15, such that only the
bristles protrude from the outer surface of the ribs.
[0083] It will be understood that a number of different tool
elements having scraper blades, bristles or pads could be provided
for a variety of cleaning operations.
[0084] FIG. 5 shows the apparatus 10 in an alternative
configuration, generally depicted at 130, in which the recesses 11
are provided with inserts flush to the outer surface of the ribs
15. In this embodiment, the tool may be run in wellbore of diameter
substantially equal to the outer diameter of the ribs 15 and the
flow guides 16 and perform a number of different stabilising,
centralising, reaming, cleaning or scraping functions.
[0085] The arrangement of the leading set of flow guides 16, the
various channels 14 defined by the ribs 15, and the trailing set of
flow guides 16 define a number of flow paths for flow of fluid
across the main body 12 of the apparatus 10. These various flow
paths provide an efficient mixing of constituents of the downhole
medium, preventing blockage of the flow paths and in particular of
the channels 14, in use.
[0086] The apparatus 10 additionally defines a number of cutting or
abrading surfaces, for reaming a borehole, or for cleaning an inner
surface of tubing in which the apparatus is located. In more
detail, the end of each flow guide 16 typically forms a relatively
aggressive cleaning blade or scraper for reaming/cleaning during
passage of the apparatus downhole. In a similar fashion, the end of
each trailing flow guide 16 defines less aggressive blades or
scrapers, to provide a reaming/cleaning function when the apparatus
is translated uphole. Also, each of the ends of the guides 16 and
the edges of the ribs 15 may define blades or scrapers, for
providing a rotary reaming/cleaning function. Furthermore, radially
outer surfaces of the apparatus 10, such as outer surfaces of the
ribs 15 and guides 16 may define or include abrasive particles, and
may, for example, be coated with Tungsten-Carbide grit.
[0087] Particular applications for which flush inserts are provided
include applications when the apparatus is used as a sleeve or
housing for a downhole tool such as a downhole motor, and serves to
centralise or support the tool within a bore hole or existing
tubing.
[0088] Flush inserts may also be used where the apparatus forms
part of a casing shoe or a drill shoe. The apparatus may for
example for part of a casing shoe reamer which assists the passage
of a casing string into a drilled wellbore.
[0089] There now follows a description of the details of the
attachment between the main body of the apparatus and the tool
elements.
[0090] FIG. 6 is a plan view of a recess 11 formed in a rib 15 on a
tubular body 12. FIG. 7 shows a cross section through a different
tubular body 12' having three recesses 11' formed therein. Although
the embodiment of FIG. 3 lacks the ribs of the embodiment of FIG.
2, the shape and form of the recesses 11' and the attachment means
are identical to recesses 11.
[0091] The recesses 11, 11' comprise a base surface having a first
portion 21 formed to a specified depth below the outer surface of
the body 12. The first portion 21 extends along the entire length
of the longitudinal recesses 11, 11', and the surface of the first
portion lies in a plane substantially aligned perpendicular to the
normal axis of the body 12. That is, the first portion 21 forms the
base of a square section recess.
[0092] The recesses 11, 11' also comprise a second portion 22
extending along the entire length of the longitudinal recess 11,
and forming the junction between the first portion 21 and a side
wall 24 of the recess. The surface of the second portion lies in a
plane inclined with respect to the first portion 21 and the side
wall 24, and the second portion 22 therefore forms a surface
inclined to the normal axis of the body.
[0093] The first and second portions 21, 22 of the base surface are
provided with threaded bores 31, 32 and 33 for receiving screws for
attachment of tool elements. Bores 31 are provided in the first
portion 21 along a central longitudinal axis of the recess. The
bores 31 are substantially radially aligned, to receive a screw
aligned on the normal axis of the main body 12, through a
corresponding bore in the removable tool element.
[0094] Bores 33 are provided close to the corners of the recess 11,
and are similarly radially aligned to receive screws aligned on the
normal axis of the main body 12, through corresponding bores in the
tool elements. This attachment arrangement is suitable for
attaching, for example, the brush assemblies as shown in FIG.
3.
[0095] Bores 32 are provided in the second portion 22, and are
aligned normally to the inclined surface of the second portion, as
most clearly shown in FIG. 6.
[0096] In the arrangement of FIG. 6, tool elements 34 have a
cross-sectional profile to fit with the cross-sectional profile of
the recess 11'. In this example, one edge of the tool element 34 is
provided with a shoulder 35 which abuts the outer surface of the
body 12' along the edge of the recess 11'.
[0097] The tool element 34 has a prismatic profile that is formed
to fit closely into the recess 11'. The depth of the pocket 11 and
thickness of the tool element is sufficient that displacement by
tangential or longitudinal forces is limited or avoided.
[0098] The tool elements 34 are secured to the tubular body 12' by
means of screws (not shown) that are provided through a securing
bore 36 in the tool element 34. The bore 36 extends from a
scalloped opening 38 provided in an edge 39 of the tool element 34.
The holes 36 align with threaded holes 32 in the body 12' in the
angular surface 22 of the recess 11'. The threaded holes 32 engage
and secure to a mating thread at the end of the screw. The head of
the screw abuts against an abutting surface in the opening 38.
[0099] In this embodiment, the positioning of the bore opening 38
and the screw head at a side of the tool element 34 prevents
interference with the operational part of the tool element.
Further, the attachment arrangement is such that upon clockwise
rotation of the tool in the wellbore, forces imparted on the tool
element 34 by the wellbore walls will tend to be directed axially
along the longitudinal axis of the screws and will therefore tend
to prevent the screw from being subjected to non co-axial stresses
and strains.
[0100] The attachment arrangement of FIG. 7 provides additional
advantages in relation to tool elements with a large depth or
radial dimension, such as stabiliser blades. If a stabiliser blade
is required to give 6'' (15 cm) stand-off between a wellbore wall
and the main body of the tool, a screw normally aligned through the
tool element may be required to be up to 12'' (30 cm) so that it
can extend through the full depth of the stabiliser blade and into
the body 12'. By providing an inclined bore and screw, the length
of the blade can be reduced. In addition, the same length of screw
could be used for all sizes of stabiliser blade.
[0101] The apparatus also provides threaded bores 31, 33 (not shown
in FIG. 7 for clarity reasons) for attachment of other tool
elements with different locations of securing holes. For example,
threaded bores 33 may be used in an alternative embodiment where
the tool elements to be located in the recesses 11, 11' have
securing holes in corresponding corners. This functionality
provides for attaching tools by the method most suited to their
performance.
[0102] It will be appreciated that the attachment arrangement of
FIG. 7 may be applied to other recess and tool element
configurations in addition to any of the embodiments described
hereto. It will also be appreciated that although the described
embodiments have an inclined bore 32 at approximately 45 degrees to
the normal axis of the body 12, other angles of inclination may be
used. Additionally, in alternative embodiments the inclined surface
profile may differ, and include additional portions with different
angles of inclination, or indeed curved portions. Although it is
preferred that the surface profile includes at least one angled or
curved portion, it is not an essential part of the invention. It
will be understood that an inclined axis for the attachment means
provides the benefits and advantages described above.
[0103] FIGS. 8A and 8B show a further embodiment of the invention
configured as a magnetic junk recovery tool, generally depicted at
140. In this embodiment, the tool comprises a tubular body having
male and female rotary shouldered connection 142a and 142b at first
and second ends respectively. In this embodiment, the tool
comprises two sets of ribs 15a and 15b, having respectively two
sets of recesses 11a and 11b. One set of hex pads 144 are located
in between sets of ribs and recesses. The tool 140 can therefore be
considered as a pair of tools 10 of FIG. 1 run in tandem. As
before, the tool is provided with leading and trailing flow guide
146.
[0104] As in the embodiment of FIG. 1, each set of ribs 15
comprises three ribs circumferentially displaced at 120 degrees.
However, the blades 15b are rotationally off-set with respect to
blades 15a by 60 degrees. This causes the ribs 15b to be aligned
with the flow path defined by ribs 15a. The provision of the two
sets of recesses rotationally off-set provides maximum
circumferential coverage when running the tool in the wellbore.
[0105] The recesses 11a and 11b are provided with magnetic inserts
148. These magnetic inserts are countersunk into the recesses to
provide a pocket for containing ferrous debris, junk and cuttings
from the wellbore.
[0106] A variety of magnetic inserts could be used. For example,
the recess could be provided with a metallic plate, which on its
lower side is provided with recesses to accommodate a number of
magnets to be retained beneath the plate.
[0107] In the embodiments shown, the ribs 15 are formed to the same
height as the flow guides 146, which are gauge with the casing in
which the tool is run. However, in alternative embodiments, the
radial height of the ribs 15 could be lower than that of the flow
guides 146. This may improve the ability of the tool to collect
debris and junk from the wellbore.
[0108] It will be appreciated that the tandem design shown in FIGS.
8A and 8B could be adopted for alternative operational
configurations. For example, the cleaning tools of FIGS. 3 and 4
could comprise a tandem configuration, with one set of cleaning
tool elements rotationally off-set with respect to the other. This
would provide increased circumferential coverage of the cleaning
tool when being run in the wellbore.
[0109] It should be noted that FIG. 8B is a circumferential view of
a tool configuration very similar to that of FIG. 8A, although the
shape of the intermediate pads 144' is different.
[0110] FIG. 9 illustrates a further embodiment of the invention, in
which the tool body of FIG. 1 receives a hole opener tool element
152 to provide a hole opener tool, generally shown at 150.
[0111] The hole opening tool element comprises a support member 152
shaped to be received in the recess 11, and which extends radially
from the tool body. The support member 152 is provided with a
leading face 154 which is inclined towards the tubular body. The
face 154 provides a bearing surface for a rotary cutter blade 156,
which is mounted rotationally via a bore 158 extending through the
support member 152. When assembled, the rotary cutter member 156 is
aligned in the space defined by the flow guide members 16. The
rotary cutting member 156 does not contact the tubular body, and is
free to rotate about the axis defined by the bore 158. When
assembled, the hole opener tool consists of three support members
152 and cutting members 156, one for each of the recesses 11.
[0112] The tool 150 may be part of kit of parts comprising a
plurality of tool elements including hole opener tool elements.
Hole opener tool elements of different radial dimensions may be
provided, such that tool elements are available to increase the
diameter of a well bore to a specific size. The tool may also be
configured in tandem, such that a hole opener tool of a first bit
size, for example 17% inches (445 millimetres) is provided below a
second hole opener tool having bit size of 26 inches (660
millimetres).
[0113] In this embodiment, the tool is also provided with jetting
port 160 located in the outer surface of the flow guide 16. The
jetting port provides a flow path from the internal bore of the
tool to the exterior of the tool. The jetting port 160 is
configured to direct a fluid towards the rotary cutters 156 to
remove cuttings from the cutting blades.
[0114] It should be appreciated that tool elements for carrying out
operations other than those described above could also be employed
by attaching them into pockets in a manner similar to the tool
elements of the previously described embodiments. For example, the
recess may receive a roller reamer tool element.
[0115] It will be understood that in certain embodiments, the shape
and configuration of the ribs may vary. For example, the ribs may
be helically oriented.
[0116] The multi-functional downhole tool as described in the above
embodiments provides a number of advantages. The ribs 15 allow
brushes, scrapers, blades or other tool elements to be attached and
engage with the wellbore over the length of the ribs. Tool elements
with relatively large surface and operational area may therefore be
employed whilst fluid flow is spatially well-accommodated.
[0117] In addition, the provision of ribs 15 to create a channel 15
in the tool portion 5 and perturbations imparted on the fluid flow
improves the efficiency of removing material and flow fluid away
from and past the downhole tool during operation, particularly in a
mode of operation where the tool is run with minimal stand-off.
Further, flow guides 16 assist in the above flow by breaking down
globules of particles or other material that may be present in the
fluid.
[0118] Another advantage is that the tool minimises costs arising
from operational wear as it is only necessary to change out and
replace the particular elements that are worn. Further, the simple
attachment arrangement promotes easy handling and replacement in
the field and is relatively quick to replace. Furthermore, the
flexibility of using a generic tubular member can reduce the
initial capital expenditure that would otherwise be required when
using separate tools for different purposes.
[0119] The present invention provides an improved system for
performing a number of downhole functions whilst efficiently
removing borehole fluid, particles and debris from a well bore.
[0120] In use, the multi-functional downhole tool is typically
attached as part of a drill string upon which torque is imparted
during drilling of a well. The tool allows removable attachment of
different tool elements for performing various functions during
rotary drilling and upon insertion and extraction of the drill
string from the well. Tool elements such as brushes or scrapers or
wipers are screwed into pockets provided in pads located on the
downhole tool by securing them to. This may be necessary for
commencing new operations or to replace worn tool elements.
[0121] Whilst the string containing the tool is located in the well
bore, functions such as cleaning, scraping or stabilising of the
wellbore may be carried out whilst rotary drilling is taking place.
As drilling is progressing, drill fluid is pumped through the
central annulus of the tool string and returned up through the
annulus of the wellbore created between the string and the wellbore
wall. Flow guides and tool elements provided on the tubular channel
the flow of fluid up through the annular space. The flow guides
help to break up material located in the flow preventing the tools
from clogging and enhancing performance.
[0122] While the invention has been described with respect to
preferred embodiments, those skilled in the art will readily
appreciate that various changes and/or modifications can be made to
the invention without departing from the spirit or scope of the
invention as defined by the appended claims.
* * * * *