U.S. patent application number 12/264591 was filed with the patent office on 2010-05-06 for downhole mud motor and method of improving durabilty thereof.
This patent application is currently assigned to BAKER HUGHES INCORPORATED. Invention is credited to Dirk Froehlich, Hendrik John, Thomas Jung, Volker Krueger.
Application Number | 20100108393 12/264591 |
Document ID | / |
Family ID | 42130051 |
Filed Date | 2010-05-06 |
United States Patent
Application |
20100108393 |
Kind Code |
A1 |
John; Hendrik ; et
al. |
May 6, 2010 |
DOWNHOLE MUD MOTOR AND METHOD OF IMPROVING DURABILTY THEREOF
Abstract
Disclosed herein is a downhole mud motor. The mud motor
includes, a stator, a rotor in operable communication with the
stator, a polymer in operable communication with the stator and the
rotor, and a plurality of carbon nanotubes embedded in the
polymer.
Inventors: |
John; Hendrik; (Celle,
DE) ; Krueger; Volker; (Celle, DE) ; Jung;
Thomas; (Eicklingen, DE) ; Froehlich; Dirk;
(Moore, OK) |
Correspondence
Address: |
CANTOR COLBURN, LLP
20 Church Street, 22nd Floor
Hartford
CT
06103
US
|
Assignee: |
BAKER HUGHES INCORPORATED
Houston
TX
|
Family ID: |
42130051 |
Appl. No.: |
12/264591 |
Filed: |
November 4, 2008 |
Current U.S.
Class: |
175/107 |
Current CPC
Class: |
E21B 4/02 20130101 |
Class at
Publication: |
175/107 |
International
Class: |
E21B 4/00 20060101
E21B004/00 |
Claims
1. A downhole mud motor, comprising a stator; a rotor in operable
communication with the stator; and a plurality of carbon nanotubes
embedded in at least a portion of the stator.
2. The downhole mud motor of claim 1, wherein the stator includes a
polymer.
3. The downhole mud motor of claim 2, wherein the polymer is
positioned between the stator and the rotor.
4. The downhole mud motor of claim 2, wherein the plurality of
carbon nanotubes are configured to increase heat transfer through
the polymer.
5. The downhole mud motor of claim 2, wherein the plurality of
carbon nanotubes are configured to increase heat transfer from the
polymer to matter that comes into contact therewith.
6. The downhole mud motor of claim 2, wherein the plurality of
carbon nanotubes interface with a surface of the polymer to reduce
friction between the polymer and matter engagable therewith.
7. The downhole mud motor of claim 2, wherein the plurality of
carbon nanotubes decreases heat generated related to deformation of
the polymer.
8. The downhole mud motor of claim 1, wherein the plurality of
carbon nanotubes allows the downhole mud motor to have a greater
power density.
9. A method of improving durability of a mud motor stator,
comprising: dissipating heat through the mud motor stator with
carbon nanotubes embedded in at least a portion of the stator; and
maintaining temperature of the mud motor stator below a threshold
temperature.
10. The method of improving durability of a mud motor stator of
claim 9, further comprising: interfacing a surface of at least a
portion of the mud motor stator with the carbon nanotubes; and
decreasing friction between the surface and matter in contact
therewith.
11. The method of improving durability of a mud motor stator of
claim 9, further comprising decreasing heat generated in relation
to deformation of at least a portion of the mud motor stator with
the carbon nanotubes embedded therein.
12. The method of improving durability of a mud motor elastomer of
claim 9, wherein the at least a portion of the stator is an
elastomer.
13. The downhole mud motor of claim 2, wherein the carbon nanotubes
are embedded in the polymer.
14. The downhole mud motor of claim 2, wherein the polymer is an
elastomer.
Description
BACKGROUND
[0001] Downhole tools used in the hydrocarbon recovery industry
often experience extreme conditions, such as, high temperatures and
high pressures, for example. These high temperatures can be
elevated further by heat generated in by the tools themselves. Mud
motors, for example, can generate additional heat during operation
thereof. Materials used to fabricate the various components that
make up the downhole tools are therefore carefully chosen for their
ability to operate, often for long periods of time, in these
extreme conditions.
[0002] Many polymeric materials have maximum operating temperature
ranges, that when exceeded, result in early failure of components
made therefrom. Advancements in the field that allow tools to
operate below these temperature ranges are well received in the
art.
BRIEF DESCRIPTION
[0003] Disclosed herein is a downhole mud motor. The mud motor
includes, a stator, a rotor in operable communication with the
stator, a polymer in operable communication with the stator and the
rotor, and a plurality of carbon nanotubes embedded in the
polymer.
[0004] Further disclosed herein is a method of improving durability
of a mud motor elastomer. The method includes, dissipating heat
through the mud motor elastomer with carbon nanotubes embedded
therein, and maintaining temperature of the mud motor elastomer
below a threshold temperature.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The following descriptions should not be considered limiting
in any way. With reference to the accompanying drawings, like
elements are numbered alike:
[0006] FIG. 1 depicts a side view of a mud motor disclosed
herein;
[0007] FIG. 2 depicts a cross sectional view of the mud motor of
FIG. 1; and
[0008] FIG. 3 depicts a cross sectional view of the mud motor of
FIG. 2 taken along arrows 3-3.
DETAILED DESCRIPTION
[0009] A detailed description of one or more embodiments of the
disclosed apparatus and method are presented herein by way of
exemplification and not limitation with reference to the
Figures.
[0010] Referring to FIGS. 1-3, an embodiment of a downhole mud
motor 10 disclosed herein is illustrated. The mud motor 10, among
other things, includes, a stator 14, a rotor 18 and a polymer 22,
also referred to herein as an elastomer, positioned between the
stator 14 and the rotor 18. Mud 26, pumped through the mud motor 10
flows through cavities 30 defined by clearances between lobes 34 of
the stator 14 and the elastomer 22 and lobes 38 of the rotor 18.
The mud 26, being pumped through the cavities 30, causes the rotor
18 to rotate relative to the stator 14 and the elastomer 22. The
elastomer 22 is sealingly engaged with both the stator 14 and the
rotor 18 to minimize leakage therebetween that could have a
detrimental effect on the performance and efficiency of the mud
motor 10. The elastomer 22, of embodiments disclosed herein, has
carbon nanotubes 42 (CNT) embedded therein to increase heat
transfer through the elastomer 22 and into the stator 14, the rotor
18 and the mud 26. The increased heat transfer, provided by the
carbon nanotubes 42, permits temperatures of the elastomer 22 to
more quickly adjust toward temperatures of matter contacting the
elastomer 22 than would occur if the carbon nanotubes 42 were not
present.
[0011] The operating temperature of the elastomer 22 can affect the
durability of the elastomer 22. Typically, the relationship is such
that the durability of the elastomer 22 reduces as the temperature
increases. Additionally, temperature thresholds exist, for specific
materials, that when exceeded will significantly reduce the life of
the elastomer 22.
[0012] The elevated operating temperatures of the mud motor 10 are
due, in part, to the high temperatures of the downhole environment
in which the mud motor 10 operates. Additional temperature
elevation, beyond that of the environment, is due to such things
as, frictional engagement of the elastomer with one or more of the
stator 14, the rotor 18 and the mud 26, and to hysteresis energy,
in the form of heat, developed in the elastomer 22 during operation
of the mud motor 10, for example. This hysteresis energy comes from
the difference in energy required to deform the elastomer 22 and
the energy recovered from the elastomer 22 as the deformation is
released. The hysteresis energy generates heat in the elastomer 22,
called heat build-up. It is these additional sources of heat
generation within the elastomer 22 that the addition of the
nanotubes 42 to the elastomer 22, as disclosed herein, is added to
mitigate.
[0013] Several parameters effect the additional heat generation,
such as, the amount of dimensional deformation that the elastomer
22 undergoes during operation, the frictional engagement between
the elastomer 22 and the rotor 18 and an overall length 46 of the
mud motor 10, for example. Additional heat generation may be
reduced with specific settings of these parameters, and the
temperature of the elastomer 22 may be maintainable below specific
threshold temperatures. Such settings of the parameters, however,
may adversely affect the performance and efficiency of the mud
motor 10, for example, by allowing more leakage therethrough, as
well as increase operational and material costs associated
therewith. Embodiments disclosed herein allow an increase in power
density of a mud motor 10 by, for example, having a smaller overall
mud motor 10 that produces the same amount of output energy to a
bit 50, attached thereto, without resulting in increased
temperature of the elastomer 22. Additionally, the mud motor 10,
using embodiments disclosed herein, may be able to operate at
higher pressures, without leakage between the elastomer 22 and the
rotor 18, thereby leading to higher overall motor efficiencies, for
example.
[0014] The carbon nanotubes 42, disclosed in embodiments herein,
are embedded in the elastomer 22, such that, the carbon nanotubes
42 interface with a surface 54 of the elastomer 22. Having the
carbon nanotubes 42 interface with the surface 54 allows a decrease
frictional engagement to exist between the elastomer 22 and matter
that comes into contact with the surface 54, such as, the rotor 18
and the mud 26, for example. Such a decrease in friction can result
in a corresponding decrease in heat generation. Additionally, in
embodiments of the invention, the presence of the carbon nanotubes
42, embedded within the elastomer 22, decrease the hysteresis
energy and heat generation resulting therefrom.
[0015] While the invention has been described with reference to an
exemplary embodiment or embodiments, it will be understood by those
skilled in the art that various changes may be made and equivalents
may be substituted for elements thereof without departing from the
scope of the invention. In addition, many modifications may be made
to adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this invention, but that the invention will include
all embodiments falling within the scope of the claims. Also, in
the drawings and the description, there have been disclosed
exemplary embodiments of the invention and, although specific terms
may have been employed, they are unless otherwise stated used in a
generic and descriptive sense only and not for purposes of
limitation, the scope of the invention therefore not being so
limited. Moreover, the use of the terms first, second, etc. do not
denote any order or importance, but rather the terms first, second,
etc. are used to distinguish one element from another. Furthermore,
the use of the terms a, an, etc. do not denote a limitation of
quantity, but rather denote the presence of at least one of the
referenced item.
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