Note: Descriptions are shown in the official language in which they were submitted.
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CORROSION AND ABRASION RESISTANT SUCKER ROD
TECHNICAL FIELD
This disclosure relates generally to equipment utilized and operations
performed in conjunction with a subterranean well and, in an example described
below, more particularly provides a corrosion and abrasion resistant sucker
rod.
BACKGROUND
A sucker rod is typically used to transmit work from an actuator at surface
to a downhole pump in a well. The actuator may reciprocate or rotate the
sucker
rod (or both) to operate the downhole pump.
A single sucker rod may extend substantially an entire distance from the
surface actuator to the downhole pump (typically thousands of meters), in
which
case the sucker rod is of the type known to those skilled in the art as a
"continuous" sucker rod. In other situations, many sucker rods (e.g., having
lengths of -20-30 ft. or 6-9 m) may be connected together, in order to extend
the
distance between the surface actuator and the downhole pump.
Therefore, it will be appreciated that improvements are continually needed
in the arts of designing, producing and utilizing sucker rods. The disclosure
below
provides such improvements.
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BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a representative partially cross-sectional view of an example of a
well system and associated method which can embody principles of this
disclosure.
FIG. 2 is a representative schematic view of an example of a sucker rod
surface treatment method which can embody the principles of this disclosure.
FIG. 3 is a representative schematic view of another example of the
sucker rod surface treatment method.
FIG. 4 is a representative perspective view of a sucker rod treated using
the FIG. 3 method.
FIG. 5 is a representative schematic view of another example of the
sucker rod surface treatment method.
FIG. 6 is a representative perspective view of a sucker rod treated using
the FIG. 5 method.
FIG. 7 is a representative schematic view of another example of the
sucker rod surface treatment method.
FIG. 8 is a representative perspective view of a sucker rod treated using
the FIG. 7 method.
DETAILED DESCRIPTION
Representatively illustrated in FIG. 1 is a system 10 and associated
method for use with a subterranean well, which system and method can embody
principles of this disclosure. However, it should be clearly understood that
the
system 10 and method are merely one example of an application of the
principles
of this disclosure in practice, and a wide variety of other examples are
possible.
Therefore, the scope of this disclosure is not limited at all to the details
of the
system 10 and method described herein and/or depicted in the drawings.
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In the FIG. 1 example, a walking beam-type surface pumping unit 12 is
mounted on a pad 14 adjacent a wellhead 16. A rod string 18 extends into the
well and is connected to a downhole pump 20 in a tubing string 22.
Reciprocation
of the rod string 18 by the pumping unit 12 causes the downhole pump 20 to
.. pump fluids (such as, liquid hydrocarbons, gas, water, etc., and
combinations
thereof) from the well through the tubing string 22 to surface.
The pumping unit 12 as depicted in FIG. 1 is of the type known to those
skilled in the art as a "conventional" pumping unit. However, in other
examples,
other types of walking beam pumping units (such as, those known to persons
skilled in the art as Mark II, reverse Mark, beam-balanced and end-of-beam
pumping units), hydraulic, rotary or other types of pumping units may be used.
The pumping unit 12 or other actuator may rotate the rod string 18 instead of,
or
in addition to, reciprocating the rod string. Thus, the scope of this
disclosure is
not limited to use of any particular type or configuration of pumping unit.
The rod string 18 may comprise a substantially continuous rod, or may be
made up of multiple connected together rods (also known as "sucker rods"). At
an
upper end of the rod string 18, a polished rod 24 extends through a stuffing
box
26 on the wellhead 16. An outer surface of the polished rod 24 is finely
polished
to avoid damage to seals in the stuffing box 26 as the polished rod
reciprocates
upward and downward through the seals.
In the FIG. 1 example, a carrier bar 28 connects the polished rod 24 to a
bridle 30. The bridle 30 in this example comprises multiple cables that are
secured to and wrap partially about a horsehead end of a beam of the pumping
unit 12. In other examples, a hydraulic actuator, a motor or another type of
actuator may be used to displace the polished rod 24 and the remainder of the
rod string 18.
As depicted in FIG. 1, the rod string 18 includes the polished rod 24, the
sucker rod(s) 32 and any adapters/connectors used to operatively connect the
rod string to the downhole pump 20. It will be appreciated that the sucker rod
32
is exposed to fluids in the tubing, which may include corrosive agents (such
as,
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acid gases in the production stream, CO2 and/or H2S). This can lead to
eventual
failure, or the need to more frequently replace the sucker rod 32.
In addition, the sucker rod 32 is subject to damage due to shipping and
handling, installation in the well and the pumping operation. If a corrosion
resistant coating has been applied to the sucker rod 32, the coating could be
breached by impacts, wear and abrasion at any point during shipping, handling,
installation and operation. It would be beneficial to be able to protect a
corrosion
resistant layer on a sucker rod from such damage.
Referring additionally now to FIG. 2, an example of a sucker rod surface
treatment method 34 is representatively illustrated in schematic form. The
sucker
rod 32 depicted in FIG. 2 may be used in the system 10 and method of FIG. 1,
or
it may be used in other systems and methods.
In the FIG. 2 method 34, the sucker rod 32 traverses multiple stations 36,
38, 40, 42, 44, 46 of a surface treatment system 48 as part of, or subsequent
to,
manufacture of the sucker rod. In other examples, the surface treatment system
48 may include other stations, other numbers of stations and different
combinations of stations. Thus, the scope of this disclosure is not limited to
the
particular stations, number of stations or combinations of stations in the
surface
treatment system 48 as described herein or depicted in the drawings.
The method 34 may be performed prior to, or after, a base metal of the
sucker rod 32 is in its final form. The method 34 may be performed for sucker
rod
32 that is otherwise ready for installation in a well, or as part of initial
manufacture
of the sucker rod.
The input drive 36 is used to displace the sucker rod 32 through the other
stations 40, 42, 44, 46. An output drive 38 may be used instead of, or in
addition
to, the input drive 36. If the surface treatment method 34 is part of an
overall
manufacturing operation, separate drives 36, 38 may not be included in the
surface treatment system 48.
The sucker rod 32 displaces from left to right through the stations 40, 42,
44, 46 as viewed in FIG. 2. Thus, the sucker rod 32 displaces first through
the
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surface preparation station 40 (after the input drive 36, if included), then
through
the heating station 42 and application stations 44, 46.
The surface preparation station 40 in the FIG. 2 example includes an
abrader 50, a cleaner 52 and a dryer 54. In other examples, other or different
elements may be used in the surface preparation station 40, or the surface
preparation station may not be used or may be integrated with one or more
other
stations.
The abrader 50 removes surface debris and any rust, and provides
surface roughness for enhanced adherence of coatings, extrusions, layers,
bonds, etc. later applied in the method 34.
The cleaner 52 removes undesired chemicals or other substances from
the sucker rod surface. The cleaner 52 may use solvents, detergents or other
cleaning agents for this purpose.
The dryer 54 removes any remaining cleaner and any undesired
particulate matter or other debris from the surface of the sucker rod 32. The
dryer
54 may produce a forced air flow, whether or not the air is also heated.
The heating station 42 in the FIG. 2 example includes an induction heater
56. In other examples, other types of heaters may be used, or the heater 56
may
be integrated with one or more other stations (such as, one or both of the
application stations 44, 46).
The application station 44 applies a corrosion resistant layer to the sucker
rod 32. In this example, the corrosion resistant layer is applied directly to
the
base metal of the sucker rod 32, but in other examples a primer, an adhesive,
a
sealer or another type of layer may be applied to the base metal prior to the
corrosion resistant layer being applied.
The corrosion resistant layer may be applied using a spray or powder
coating technique. The corrosion resistant layer may comprise a thermosetting
polymer material (such as a fusion bond epoxy), in which case the heat
provided
by the heating station 42 is selected to cause the material to form a coating
that
completely encloses the base metal of the sucker rod 32.
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In other examples, the sucker rod 32 could be dipped or wrapped in a
corrosion resistant material as the sucker rod passes through the application
station 44. The corrosion resistant layer could be extruded onto the base
metal of
the sucker rod 32. Thus, the scope of this disclosure is not limited to any
particular technique for incorporating the corrosion resistant layer into the
sucker
rod 32.
The application station 46 applies an abrasion resistant layer to the sucker
rod 32. In this example, the abrasion resistant layer is applied directly to
the
corrosion resistant layer of the sucker rod 32, but in other examples a
primer, an
adhesive, a sealer or another type of layer may be applied to the corrosion
resistant layer prior to the abrasion resistant layer being applied.
The abrasion resistant layer may be applied using a spray or powder
coating technique. The abrasion resistant layer may comprise a thermosetting
polymer material (such as, a phenolic or a phenolic and fusion bond epoxy
.. composition), in which case the heat provided by the heating station 42 is
selected to cause the material to form a coating that completely encloses the
corrosion resistant layer of the sucker rod 32.
In other examples, the sucker rod 32 could be dipped or wrapped in an
abrasion resistant material as the sucker rod passes through the application
.. station 46. The abrasion resistant layer could be extruded onto the
corrosion
resistant layer. Thus, the scope of this disclosure is not limited to any
particular
technique for incorporating the abrasion resistant layer into the sucker rod
32.
The abrasion resistant layer protects the corrosion resistant layer against
damage due to impacts, wear and abrasion. In addition, the abrasion resistant
layer can in some examples reduce friction between the sucker rod 32 and the
tubing string 22 during operation.
Referring additionally now to FIGS. 3 & 4, another example of the surface
treatment system 48 and method 34 is representatively illustrated, along with
an
example sucker rod 32 produced by the system and method. In FIG. 3, the
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stations 40, 42, 44, 46 are depicted in simplified form. The input and output
drive
stations 36, 38 are not depicted in FIG. 3, but could be included if desired.
In FIG. 4, the sucker rod 32 is depicted with both of the corrosion resistant
layer 58 and the abrasion resistant layer 60 on a base metal 62. The corrosion
resistant layer 58 is applied over the base metal 62 in the application
station 44,
and the abrasion resistant layer 60 is applied over the corrosion resistant
layer 58
in the application station 46.
The base metal 62 may be any material suitable for transmitting work from
the surface actuator 12 to the downhole pump 20 (see FIG. 1) and otherwise
operating in a well environment. If the sucker rod 32 is a continuous sucker
rod,
the base metal 62 may have a length of 1000 meters or greater.
The base metal 62 should have suitable strength and toughness for
transmitting torque and tensile loads, particularly fatigue strength to
withstand
varying loads for long periods of time, and yet be economical to obtain and
process. Some examples of suitable materials for the base metal 62 include
carbon and low alloy steels. However, the scope of this disclosure is not
limited to
use of any particular material in the base metal 62.
In this example, the corrosion resistant layer 58 is suitable for preventing
corrosion of the base metal 62 due to exposure to fluids in a well. The
corrosion
resistant layer 58 comprises a corrosion resistant material 64. Examples of
suitable corrosion resistant materials include fusion bonded epoxy and other
thermosetting polymers such as silicone, polyurethane, phenolic and polyester.
The corrosion resistant material 64 may mitigate corrosion by isolating the
base metal 62 from well fluids, by chemically hindering a corrosive reaction,
or by
another means. The corrosion resistant material 64 may be applied by spraying,
dipping, wrapping, extruding or any other technique. The scope of this
disclosure
is not limited to use of any particular type of corrosion resistant material
or
manner of applying the corrosion resistant material.
In the FIGS. 3 & 4 example, the corrosion resistant layer 58 is applied
directly to the base metal 62. In some examples, an adhesive, primer, sealer
or
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other layer may be included between the corrosion resistant layer 58 and the
base metal 62.
The abrasion resistant layer 60 is suitable for preventing damage to the
corrosion resistant layer 58 due to various impacts, wear and abrasion
experienced by the sucker rod 32. The abrasion resistant layer 60 comprises an
abrasion resistant material 66. Examples of suitable abrasion resistant
materials
include phenolics, fusion bonded epoxy and other thermosetting polymers,
polyolefins and other thermoplastic polymers, hard particles or friction
reducing
particles, and combinations thereof.
The abrasion resistant material 66 may mitigate abrasion by reducing
friction, by presenting a hard or tough surface, or by another means. The
abrasion resistant material 66 may be applied by spraying, dipping, wrapping,
extruding or any other technique. The scope of this disclosure is not limited
to
use of any particular type of abrasion resistant material or manner of
applying the
abrasion resistant material.
In the FIGS. 3 & 4 example, the abrasion resistant layer 60 is applied
directly to the corrosion resistant layer 58. In some examples, an adhesive,
primer, sealer or other layer may be included between the abrasion resistant
layer 60 and the corrosion resistant layer 58.
Referring additionally now to FIGS. 5 & 6, another example of the surface
treatment method 34 and system 48, and the sucker rod 32 produced thereby,
are representatively illustrated. The FIGS. 5 & 6 example is similar in many
respects to the FIGS. 3 & 4 example, except that a particulate material 68 is
applied over the corrosion resistant layer 58.
The particulate material 68 is applied by an application station 70. The
application station 70 is positioned between the application stations 44, 46
as
depicted in FIG. 5.
The particulate material 68 may be any material suitable to resist impact,
wear or abrasion. The resistance to impact, wear or abrasion may be due to a
relatively high strength, hardness or toughness of the particulate material
68. The
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particulate material 68 may comprise silicon carbide, silicon dioxide (e.g.,
sand),
carbides, nitrides, oxides, borides, minerals, or other suitable materials.
The
particulate material 68 may be selected from a variety of friction reducing
agents,
including fluorocarbons, graphite, graphene, molybdenum disulfide and other
friction reducing agents. The scope of this disclosure is not limited to use
of any
certain particulate material.
The application station 70 may apply the particulate material 68 directly to
the corrosion resistant layer 58, or another layer may be applied between the
particulate material and the corrosion resistant layer. For example, an
adhesive
could be applied to the corrosion resistant layer 58 prior to applying the
particulate material 68 onto the adhesive. The particulate material 68 may
embed
partially or fully into the corrosion resistant layer 58.
The remainder of the abrasion resistant layer 60 is applied by the
application station 46, for example, as described above for the FIGS. 3 & 4
example. However, in the FIGS. 5 & 6 example, the abrasion resistant layer 60
includes the particulate material 68 in a matrix material 66a. The matrix
material
66a may be the same as the abrasion resistant material 66 in the FIGS. 3 & 4
example. Thus, the abrasion resistant material 66 in the FIGS. 5 & 6 example
includes both the particulate material 68 and the matrix material 66a.
When the matrix material 66a is applied to the corrosion resistant layer 58,
the particulate material 68 is "absorbed" into the matrix material, so that
the
matrix and particulate materials become a single composite element. In some
examples, the particulate material 68 may become dispersed or embedded in the
matrix material 66a.
Referring additionally now to FIGS. 7 & 8, another example of the surface
treatment method 34 and system 48, and the sucker rod 32 produced thereby,
are representatively illustrated. The FIGS. 7 & 8 example is similar in many
respects to the FIGS. 5 & 6 example, except that the abrasion resistant layer
60
(including the particulate material 68 and the matrix material 66a) is applied
by
the application station 46.
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The abrasion resistant material 66 in this example includes both the matrix
material 66a and the particulate material 68. The matrix and particulate
materials
66a, 68 may be combined to form the abrasion resistant material 66, prior to
the
application station 46 applying the abrasion resistant material onto the
corrosion
.. resistant material 64 (or any layer applied on the corrosion resistant
layer).
In some examples, the matrix material 66a could comprise a thermoplastic
material. The application station 46 can be configured to extrude the
thermoplastic matrix material 66a, along with the particulate material 68
embedded therein, onto the corrosion resistant layer 58. However, if the
.. corrosion resistant material 64 comprises a thermosetting material, an
adhesive
or other tie layer may be used between the corrosion resistant layer 58 and
the
abrasion resistant layer 60.
It may now be fully appreciated that the above disclosure provides
significant advancements to the art of designing, producing and utilizing
sucker
.. rods for use in wells. In examples described above, a corrosion resistant
layer 58
is applied on a base metal 62 of a sucker rod 32, and the corrosion resistant
layer
58 is protected by an abrasion resistant layer 60. An abrasion resistant
material
66 of the abrasion resistant layer 60 may comprise a phenolic based matrix
material 66a and/or a particulate material 68.
The above disclosure provides to the art a sucker rod 32 for use in a
subterranean well. In one example, the sucker rod 32 may comprise a base metal
62 configured to connect a surface actuator 12 to a downhole pump 20, a
corrosion resistant layer 58 on the base metal 62, and an abrasion resistant
layer
60 external to the corrosion resistant layer 58. The abrasion resistant layer
60
comprises a phenolic material 66a.
In any of the examples described herein, the abrasion resistant layer 60
may further comprise an epoxy material.
In any of the examples described herein, the abrasion resistant layer 60
may comprise an abrasion resistant particulate material 68.
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In any of the examples described herein, the abrasion resistant layer 60
may comprise a friction reducing particulate material 68.
In any of the examples described herein, the particulate material 68 may
be embedded in the phenolic material 66a.
In any of the examples described herein, the particulate material 68 may
be positioned between the corrosion resistant layer 58 and at least a portion
of
the phenolic material 66a.
In any of the examples described herein, the particulate material 68 may
be selected from the group consisting of silicon carbide, silicon dioxide,
oxides,
borides, nitrides and carbides.
In any of the examples described herein, the particulate material 68 may
be selected from a variety of friction reducing agents, including
fluorocarbons,
graphite, graphene, molybdenum disulfide and other friction reducing agents.
In any of the examples described herein, the corrosion resistant layer 58
may comprise an epoxy material.
In any of the examples described herein, the sucker rod 32 may be a
continuous sucker rod.
In any of the examples described herein, the base metal 62 may have a
length of at least 1000 meters.
Another sucker rod 32 for use in a subterranean well is provided to the art
by the above disclosure. In this example, the sucker rod 32 comprises a base
metal 62 configured to connect a surface actuator 12 to a downhole pump 20, a
corrosion resistant layer 58 on the base metal 62, and an abrasion resistant
layer
60 external to the corrosion resistant layer 58. The abrasion resistant layer
60
comprises an abrasion resistant particulate material 68 and a matrix material
66a.
In any of the examples described herein, the matrix material 66a may
comprise a phenolic material.
In any of the examples described herein, the particulate material 68 may
be embedded in the matrix material 66a.
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In any of the examples described herein, the particulate material 68 may
be positioned between the corrosion resistant layer 58 and at least a portion
of
the matrix material 66a.
A method 34 of producing a continuous sucker rod 32 is also provided to
the art by the above method. In one example, the method 34 comprises
displacing the continuous sucker rod 32 through a surface treatment system 48;
applying a corrosion resistant layer 58 on a base metal 62 of the continuous
sucker rod 32; then applying an abrasion resistant layer 60 external to the
corrosion resistant layer 58.
In any of the examples described herein, the abrasion resistant layer 60
applying step may comprise applying a phenolic material 66a.
In any of the examples described herein, the abrasion resistant layer 60
applying step may comprise applying an abrasion resistant and/or friction
reducing particulate material 68.
In any of the examples described herein, the abrasion resistant layer 60
applying step may comprise applying an abrasion resistant and/or friction
reducing particulate material 68 dispersed in a matrix material 66a.
Although various examples have been described above, with each
example having certain features, it should be understood that it is not
necessary
for a particular feature of one example to be used exclusively with that
example.
Instead, any of the features described above and/or depicted in the drawings
can
be combined with any of the examples, in addition to or in substitution for
any of
the other features of those examples. One example's features are not mutually
exclusive to another example's features. Instead, the scope of this disclosure
encompasses any combination of any of the features.
Although each example described above includes a certain combination of
features, it should be understood that it is not necessary for all features of
an
example to be used. Instead, any of the features described above can be used,
without any other particular feature or features also being used.
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It should be understood that the various embodiments described herein
may be utilized in various orientations, such as inclined, inverted,
horizontal,
vertical, etc., and in various configurations, without departing from the
principles
of this disclosure. The embodiments are described merely as examples of useful
applications of the principles of the disclosure, which is not limited to any
specific
details of these embodiments.
The terms "including," "includes," "comprising," "comprises," and similar
terms are used in a non-limiting sense in this specification. For example, if
a
system, method, apparatus, device, etc., is described as "including" a certain
feature or element, the system, method, apparatus, device, etc., can include
that
feature or element, and can also include other features or elements.
Similarly, the
term "comprises" is considered to mean "comprises, but is not limited to."
Of course, a person skilled in the art would, upon a careful consideration
of the above description of representative embodiments of the disclosure,
readily
appreciate that many modifications, additions, substitutions, deletions, and
other
changes may be made to the specific embodiments, and such changes are
contemplated by the principles of this disclosure. For example, structures
disclosed as being separately formed can, in other examples, be integrally
formed and vice versa. Accordingly, the foregoing detailed description is to
be
clearly understood as being given by way of illustration and example only, the
spirit and scope of the invention being limited solely by the appended claims
and
their equivalents.
