U.S. patent application number 11/890977 was filed with the patent office on 2008-01-31 for wear indication apparatus and method.
This patent application is currently assigned to Baker Hughes Incorporated. Invention is credited to John P. Davis, Gerald D. Lynde.
Application Number | 20080023225 11/890977 |
Document ID | / |
Family ID | 34972226 |
Filed Date | 2008-01-31 |
United States Patent
Application |
20080023225 |
Kind Code |
A1 |
Lynde; Gerald D. ; et
al. |
January 31, 2008 |
Wear indication apparatus and method
Abstract
Apparatus and method for monitoring the wear of a downhole tool,
and providing indication of the degree of wear to an operator at
the well surface. Rotating torque can exhibit a drop when wear of
the cutting element matrix progresses to wear pads within the
matrix. Other wear indicators can also be built into the cutting
element matrix. Progression of wear down to the indicator can be
directly measured at the well surface, or relayed to the surface
via a downhole communication system.
Inventors: |
Lynde; Gerald D.; (Houston,
TX) ; Davis; John P.; (Cypress, TX) |
Correspondence
Address: |
GERALD W. SPINKS
103 EDWARDS STREET
ABBEVILLE
LA
70510
US
|
Assignee: |
Baker Hughes Incorporated
Suite 1200 3900 Essex Lane
Houston
TX
77027
|
Family ID: |
34972226 |
Appl. No.: |
11/890977 |
Filed: |
August 7, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11120655 |
May 2, 2005 |
|
|
|
11890977 |
Aug 7, 2007 |
|
|
|
60571246 |
May 13, 2004 |
|
|
|
Current U.S.
Class: |
175/39 |
Current CPC
Class: |
E21B 12/02 20130101;
B24B 49/08 20130101; E21B 10/00 20130101 |
Class at
Publication: |
175/039 |
International
Class: |
E21B 12/02 20060101
E21B012/02 |
Claims
1. A system for monitoring wear of a downhole tool, comprising: a
working profile formed on a downhole tool, said working profile
being adapted to perform work on a structure downhole in a well
bore; a wear resistant pad within said working profile, said wear
resistant pad being initially protected from physical contact with
said downhole structure by said working profile; a torque sensor
adapted to measure the torque required to rotate said downhole
tool; where said wear resistant pad is adapted to cause a drop in
said torque upon sufficient progression of wear of said working
profile to bring said downhole structure into contact with said
wear resistant pad.
2. The system recited in claim 1, further comprising an output
device adapted to provide a signal of an alteration in said
torque.
3. The system recited in claim 2, wherein said output device
comprises an operator interface.
4. The system recited in claim 3, wherein said operator interface
comprises a torque meter.
5. The system recited in claim 2, wherein said output device
comprises a control system interface adapted to provide an input
signal into a control system.
6. A method for monitoring wear of a downhole tool, comprising:
providing a wear resistant pad in a working profile of a downhole
tool; providing a torque sensor adapted to measure an operating
parameter of said downhole tool; operating said downhole tool to
perform work downhole in a wellbore; bearing weight with said wear
resistant pad when wear of said working profile has progressed
sufficiently to expose said wear resistant pad to contact with a
downhole structure; and sensing a drop in the torque required to
rotate said downhole tool with said torque sensor.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 11/120,655, filed on May 2, 2005, and entitled "Wear
Indication Apparatus and Method", which relies upon U.S.
Provisional Pat. App. No. 60/571,246, filed on May 13, 2004, and
entitled "Wear Indication Apparatus and Method."
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] This invention is in the field of methods and apparatus used
to perform downhole work in a well bore with a tool having a
working profile which wears away during use, such as a mill,
cutter, or drill bit.
[0005] 2. Background Art
[0006] In the drilling, completion, and workover of oil and gas
wells, it is common to perform work downhole in the well bore with
a tool which has some sort of wearable working profile interfacing
with a downhole structure. Examples would be milling a downhole
metal object with a milling tool, performing a washover operation
with a rotary shoe, cutting through a tubular with a cutting tool,
or drilling through formation with a drill bit. During the
performance of these operations, it is common for the working
profile of the tool, such as the cutting elements mounted on its
lower or outer face, to wear away. As this wear progresses, the
effectiveness of the tool decreases.
[0007] It is desirable to pull the tool from the well and replace
it, when the working profile has experienced a given amount of
wear. The degree of wear at which it is desirable to replace the
tool depends upon the type of tool and the operation being
performed. Unfortunately, it is difficult or even impossible for
the well operator at the Earth's surface to know accurately when
this given amount of wear has occurred. Often, the decision as to
when to pull the tool depends substantially upon the experience of
the operator. That is, the operator must estimate the amount of
tool wear based on whatever is known about the time the operation
has been underway, the weight on the tool, the type of downhole
structure being worked, the cuttings found in the drilling fluid,
or a gradual change in work string torque. None of these parameters
provides a definitive indication that the wear in the working
profile has progressed to a specific degree at which the operator
desires to pull the tool. Pulling a tool prematurely adds
unnecessary trips out of the well, adding to rig time. Pulling the
tool too late gradually decreases the effectiveness of the downhole
operation, also adding to rig time.
[0008] It is desirable to have a means for determining in a
definitive way when the wear of the working profile of the downhole
tool has progressed to a known degree, thereby allowing the
operator to make an informed decision about replacing the tool.
BRIEF SUMMARY OF THE INVENTION
[0009] The present invention provides a wear indicator imbedded in
the working profile at a depth protecting the wear indicator from
contact with the downhole structure which is to be the target of
the work performed by the working profile. As the work progresses,
the working profile wears away until the wear indicator is exposed
to contact with downhole structure, such as an object being milled
or cut, or the formation being drilled. Upon exposure, the wear
indicator changes some operating parameter related to the downhole
tool, and this change in the operating parameter is detected by the
operator or by a control system, definitively indicating a specific
amount of wear of the working profile. Multiple wear indicators can
be provided at multiple depths within the working profile, to
provide definitive indications of progressive levels of wear of the
working profile.
[0010] The wear indicator can take various forms. For example, a
pressurized fluid path can be formed within the working profile,
terminating beneath the surface. The fluid path can be pressurized,
for instance, by the drilling fluid being pumped through the tool.
When wear of the working profile progresses to the point that the
fluid path is breached, this provides an additional flow path for
the fluid out of the tool. This results in a measurable pressure
drop in the fluid, which can be detected to provide a clear
indication that the selected degree of wear has occurred. In this
case, the pressurized fluid path imbedded in the working profile is
the wear indicator, the fluid pressure is the pertinent operating
parameter being monitored, and the sensor monitoring the fluid
pressure might be a pressure gage.
[0011] As another example, wear resistant pads can be imbedded
within the working profile as wear indicators. When wear of the
working profile progresses to the point that the wear resistant
pads contact the downhole structure and bear part of the weight,
this significantly limits the milling or cutting action of the
tool, resulting in a measurable drop in the torque required to
rotate the tool, which can be detected to provide a clear
indication that the selected degree of wear has occurred. In this
case, the wear resistant pads imbedded in the working profile
constitute wear indicators, the required rotating torque is the
pertinent operating parameter being monitored, and the sensor
monitoring the rotating torque might be a torque meter.
[0012] As still another example, a quantity of a discernible
material can be encapsulated within the working profile. The
discernible material can be, for example, a magnetic powder, a
chemical tracer, or a visible material which contrasts with the
drilling fluid returning to the surface of the well. When wear of
the working profile progresses to the point that the encapsulated
material deposit contacts the downhole structure and escapes from
the working profile, the discernible material enters the fluid
flowing through the tool and returns to the surface. The escape of
this material from the working profile can be detected to provide a
clear indication that the selected degree of wear has occurred. In
this case, the capsule of discernible material imbedded in the
working profile constitutes a wear indicator, the magnetic,
chemical, or visible property of the material is the pertinent
operating parameter being monitored, and the sensor monitoring this
property would be the appropriate instrumentation or simply visual
observation.
[0013] These changes in the operating parameters of the tool,
initiated by the wear indicators, can be detected at the well
surface by operator observation of instrumentation such as a
pressure gage, a torque meter, or a sensor in the drilling fluid,
or by observation of the drilling fluid itself. Alternatively, the
operating parameter change can be detected by a sensor which
outputs a signal to a control system. Further, the changes in the
operating parameters can be detected by a downhole instrument which
then relays a wear signal to the surface. Multiple types of wear
indicators might be combined in a given tool.
[0014] The novel features of this invention, as well as the
invention itself, will be best understood from the attached
drawings, taken along with the following description, in which
similar reference characters refer to similar parts, and in
which:
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0015] FIGS. 1 and 2 are section views of a prior art mill;
[0016] FIG. 3 is an end view of a prior art mill;
[0017] FIG. 4 is an end view of a mill according to the present
invention;
[0018] FIG. 5 is a section view of the mill of FIG. 4, showing
penetration of the wear indicator by a downhole structure;
[0019] FIGS. 6 and 7 are section views of a second embodiment of
the present invention, before and after breaching of the fluid
pressure wear indicators, and before and after contact with the
wear resistant pad type wear indicators; and
[0020] FIG. 8 is a section view of a third embodiment of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] As shown in FIGS. 1 through 3, a prior art mill M is lowered
through a casing C into contact with a downhole structure to be
milled away, such as a tubular element T. The typical mill M would
have a fluid path FP for drilling or milling fluid, and the fluid
would be conducted to the working surface of the working profile WP
of the mill M via fluid nozzles as known in the art, which are only
partially shown here. The mill M is typically rotated, in order to
mill away the tubular element T with the working profile WP. The
working profile WP can be a matrix of cutting elements formed on
the lower face of the mill M, which is in this case represented as
an end mill or junk mill. For purposes of the present invention,
the tool could also be a rotary shoe, any kind of cutter, or even a
drill bit. Similarly, the working profile could be any kind of
profile mounted or formed on the tool for purposes of performing
work on any kind of downhole structure, including an earth
formation.
[0022] As seen in FIGS. 2 and 3, as the mill M is rotated, it will
mill away a portion of the tubular element T, but at the same time,
the tubular element T will wear a groove G through the cutting
element matrix which constitutes the working profile WP. When the
top of the tubular element T contacts the body of the mill M, the
cutting or milling action essentially stops. At this point, there
is little or no indication for the operator that milling has
ceased. For other types of structure being milled or drilled, the
wear pattern formed in the working profile would be different from
the circular groove shown, but the principle is the same.
[0023] FIG. 4 shows an end view of a first embodiment of a tool 10
according to the present invention. FIG. 5 shows the tool 10 in
operation. The tool 10 has a body 12, on which is formed a working
profile 14 in the form of a matrix of cutting elements. As the tool
10 is rotated, the leading face 16 of the working profile 14
contacts the tubular element T, and the working profile 14 mills
away the tubular element T. As mentioned above, at the same time,
the tubular element T will wear a circular groove in the working
profile 14. A rectangular, closed-end, fluid passage 21 is formed
within the working profile 14, imbedded below the leading surface
16 of the working profile 14. That is, the working profile 14
initially separates the fluid passage 21 from contact with the
downhole structure, represented in this case by the tubular element
T. Thus, the fluid passage 21 is represented as dashed lines in
FIG. 4, and the nozzles 19 are shown leading from the fluid path 18
to the leading face 16. FIG. 4 indicates just one example of how
the fluid passage 21 can be imbedded within the working profile 14,
without interfering with the normal flow through the nozzles 19.
The fluid passage 21 could be a tube imbedded within the working
profile 14, or it could simply be a cavity formed therein by any
known means.
[0024] FIG. 5 shows that the fluid passage 21 is actually connected
in fluid flow communication to the fluid path 18 and forms a
dead-end part thereof. As the tubular element T wears a groove into
the working profile 14, the tubular element T will eventually
breach the fluid passage 21. This provides an additional outlet
from the fluid path 18, in addition to the nozzles 19. Opening of
this additional fluid outlet causes a noticeable drop in the
backpressure in the fluid path 18, and this provides a definitive
indication that wear of the working profile 14 has progressed to
the point where the tool 10 should be replaced. So, the fluid
passage 21 provides one type of wear indicator which can give a
discernible and definitive indication of the wear of the working
profile. The pertinent operating parameter, the fluid pressure, can
be monitored by any means known in the art, such as a pressure
gage.
[0025] FIGS. 6 and 7 show a second embodiment of the tool 10, which
actually includes two additional types of wear indicators. That is,
a plurality of closed fluid passages 20, in this case a plurality
of branches, are embedded within the cutting profile 14. As with
the rectangular fluid passage 21, these fluid branches 20 could be
tubes 22 imbedded within the working profile 14, or they could
simply be passages formed therein by any known means. These fluid
branches 20 function in a similar fashion to the fluid passage 21.
Also shown in this embodiment is another type of wear indicator,
namely a plurality of pads 24 of wear resistant material.
[0026] When the working profile 14 has worn down as shown in FIG.
7, to the point where the wear resistant pads 24 contact the
downhole structure, the wear resistant pads 24 begin carrying a
substantial portion of the weight on the tool 10. This essentially
prevents any further milling or cutting action, and as a result,
the torque required to rotate the tool 10 is significantly reduced.
This discernible reduction in rotating torque can be sensed by any
means known in the art, such as a torque meter. The reduced torque
meter reading constitutes a definitive indication that the working
profile 14 has worn to a point where replacement of the tool 10 is
required. So, the wear resistant pads 24 provide another type of
wear indicator which can give a discernible and definitive
indication of the wear of the working profile. The pertinent
operating parameter, the rotating torque, can be sensed or
monitored by any means known in the art. The wear resistant pads 24
can be used in combination with the fluid branches 20, or in
combination with a rectangular fluid passage 21, or any of these
can be used separately.
[0027] FIG. 8 shows a third embodiment of the tool 10, which also
includes two types of wear indicator. As with the embodiment shown
in FIGS. 6 and 7, the wear resistant pads 24 are shown here, and
they function in the same way as described above. Additionally,
this embodiment shows a capsule 28 of a discernible medium or
material, which functions as a tell-tale agent. As with the
rectangular fluid passage 21, the capsule 28 could be a tubes 30
imbedded within the working profile 14, or it could simply be a
passage formed therein by any known means. The discernible material
might be a magnetic powder, a chemical agent, or any other material
which contrasts in some way, such as visibly, with the drilling or
milling fluid being pumped through the tool 10. Other discernible
properties might also be used, with the key point being that they
are discernible to an observer or to some type of instrumentation,
once they are released from the tool 10.
[0028] As the downhole structure wears away the working profile 14,
the downhole structure will eventually breach the material capsule
28. This releases the discernible tell-tale material from the tool
10. The discernible material can be detected either directly by an
operator or by some kind of instrumentation, and this provides a
definitive indication that wear of the working profile 14 has
progressed to the point where the tool 10 should be replaced. So,
the material capsule 28 provides another type of wear indicator
which can give a discernible and definitive indication of the wear
of the working profile. The pertinent operating parameter, the
discernible property of the material, can be monitored by any means
known in the art, such as a magnetic sensor, a chemical sensor, or
by operator observation. The material capsule 28 can be used
separately, or in combination with any of the other types of wear
indicator.
[0029] While the particular invention as herein shown and disclosed
in detail is fully capable of obtaining the objects and providing
the advantages hereinbefore stated, it is to be understood that
this disclosure is merely illustrative of the presently preferred
embodiments of the invention and that no limitations are intended
other than as described in the appended claims.
* * * * *