JP7021248B2 - Coupling for well pump components - Google Patents

Description

(Quotation of related application)
The present application claims priority to US Provisional Patent Application No. 62 / 473,792 (filed March 20, 2017), and the disclosure of the above application is hereby incorporated by reference in its entirety.

The present disclosure relates to couplings made from spinodal hardened copper alloys. Couplings are particularly useful for connecting the components of a soccer rod string to an underground pump. The alloy preferably has a slip coefficient of friction of less than 0.4 when measured against carbon steel.

A hydrocarbon extractor is typically a soccer rod lift system that connects an underground pump for extracting hydrocarbons from an underground reservoir, a power source for providing power to the pump, and the power source and the underground pump. And include. The soccer rod lift system includes a series of soccer rods that are joined together by a coupling. Rods and couplings are joined by pin and box screw connections. Additional couplings with threaded connections are also used to join the soccer rod lift system to the underground pump. Damage to the threaded connection due to galling (wear due to adhesion between sliding surfaces) can impair the mechanical integrity of the fitting and lead to a failure of the connection between the power source and the pump. In addition, the hydrocarbon extraction system operates within the conduit. Damage to the conduit and coupling caused by repeated contact between the outer surface of the coupling / pump and the inner surface of the conduit impairs the mechanical integrity of the conduit or coupling and is carried into the environment by the conduit. Can lead to either a leak of hydrocarbons or a separation of the coupling connection with the soccer rod string. In either case, it effectively shuts down the pumping process, often leading to very costly additional actions to correct such failures.

The desired properties of the coupling used in such a system include high tensile strength, high fatigue strength, high fracture toughness, galling resistance, and corrosion resistance. Traditional couplings typically consist of steel or nickel alloys, which lack the preferred inherent properties, in particular a perfect complement to wear resistance. Expensive surface treatments are typically used not only on couplings made from steel or nickel alloys, but also on the inside of conduits where the couplings are placed inside, to increase galling resistance. .. These surface treatments must eventually be reapplied periodically over the life of the part in order to wear and be effective. Further, the coatings can reduce the wear of the components to which they are applied, but the coatings are often incompatible with other components of the system to which the coatings can come into contact.

With improved inherent galling resistance, the coupling and conduit materials are compatible (during operation, they undergo minimal wear, do not require any protective coating, and the total friction loss of the pumping system. (Meaning to reduce), it would be desirable to develop new couplings with other desirable properties,

The present disclosure relates to a coupling made from a spinodal hardened copper alloy, more specifically to a coupling inserted between a soccer rod of a soccer rod string and a valve rod bushing of an underground pump. The coupling can be considered part of the soccer rod string. The coupling has a unique combination of properties including high tensile strength, high fatigue strength, high fracture toughness, galling resistance, and corrosion resistance. This combination of properties to the coupling and other components within the pump system using such coupling (eg, soccer rods and conduits) while providing mechanical functionality during the hydrocarbon recovery operation. Delay the occurrence of catastrophic damage. This also extends the useful life of such components and significantly reduces the cost of equipment used to recover hydrocarbons.

Disclosed in various embodiments herein are couplings for a soccer rod string having a core having a first end, a center, and a second end. Each of the first and second ends has an end surface. The first end has a linear taper that extends inward from the center and ends at the surface of the first end. In other words, the first end surface has a smaller diameter than the central part. The surface of the second end of the second end has a rounded edge. The coupling is made from a spinodal hardened copper-nickel-tin alloy and has reduced friction and improved wear resistance.

The diameter of the first end surface can be less than the diameter of the second end surface. In some specific embodiments, threaded bores extend throughout the core from the first end to the second end. The thread of the bore may have a Rockwell C hardness (HRC) of about 20 to about 40.

The threaded bore at the first end can be adapted to couple with a valve rod bushing that can be connected to an underground pump. The surface of the first end can abut on the shoulder portion of the valve rod bushing. The outer diameter of the coupling can exceed the outer diameter of the valve rod bushing.

The threaded bore at the second end can be adapted to join the soccer rod of the soccer rod string. The surface of the second end can abut on the shoulder portion of the soccer rod. The outer diameter of the coupling can exceed the outer diameter of the soccer rod.

Also disclosed herein is a soccer rod string comprising an end with a pin with a male thread and a valve rod bushing including an end with a pin with a male thread. Couplings are also included as described above. The threaded bore at the first end of the coupling is complementary to the male thread of the valve rod bushing and the threaded bore at the second end of the coupling is complementary to the male thread of the soccer rod. .. The coupling comprises a spinodal hardened copper-nickel-tin alloy.

Also disclosed herein is a pump system comprising an underground pump, a power source for powering the underground pump, and a rod string located between the underground pump and the power source. The rod string comprises a soccer rod comprising an end having a pin with a male thread and a valve rod bushing including an end having a pin with a male thread. Couplings are also included, as described above. The threaded bore at the first end of the coupling is complementary to the male thread of the valve rod bushing and the threaded bore at the second end of the coupling is complementary to the male thread of the soccer rod. .. The coupling comprises a spinodal hardened copper-nickel-tin alloy.

Couplings for a soccer rod string having a core with a first end, a center and a second end are also disclosed in various embodiments herein. Each of the first and second ends has an end surface. The first end has a linear taper that extends inward from the center and ends at the surface of the first end. In other words, the first end surface has a smaller diameter than the central part. The second end also has a linear taper that extends inward from the center and ends at the surface of the second end. In other words, the second end surface has a smaller diameter than the central part. The coupling is made from a spinodal hardened copper-nickel-tin alloy.

These and other non-limiting properties of this disclosure are specifically disclosed below.

The following is a brief description of the drawings, which are presented for purposes of illustrating exemplary embodiments disclosed herein, and not for the purpose of limiting them.

FIG. 1 is a side sectional view of an exemplary soccer coupling of the present disclosure, having a linear taper at one end and a rounded edge at the other end.

FIG. 2A is a partial cross-sectional view showing the engagement of a soccer coupling with a soccer rod and a valve rod bushing connected to an underground pump.

FIG. 2B is a side view showing the coupling, soccer rod, and valve rod bushing of FIG. 2A in the assembled state.

FIG. 3A is a photograph of an exemplary soccer coupling of the present disclosure, having linear tapers at both ends.

FIG. 3B is a side sectional view showing the inside of the soccer coupling of FIG. 3A.

FIG. 4 is a schematic diagram of an embodiment of the pumping system of the present disclosure.

FIG. 5 is a graph illustrating the typical slip coefficient of friction of various materials measured by sliding the material over carbon steel. The y-axis is dimensionless and ranges from 0 to 0.8 with an interval of 0.1. From left to right, the materials are nickel alloys, carbon steel, aluminum bronze, and copper-nickel-tin.

FIG. 6 is a graph illustrating wear of various materials on a steel shaft. The y-axis is an increase in clearance due to wear in inches. The y-axis ranges from 0.000 to 0.050 at intervals of 0.005. The x-axis is the number of wear cycles in the thousands, ranging from 0 to 180 at intervals of 30. The steepest line is hardened steel and the gentlest line is copper-nickel-tin.

FIG. 7 is a photograph of the soccer coupling of the present disclosure made from a Cu-15Ni-8Sn alloy.

The components, processes, and devices disclosed in this document can be more fully understood by reference to the accompanying drawings. These figures are merely schematic diagrams with an emphasis on facilitating and facilitating the manifestations of the present disclosure, and therefore do not show the relative dimensions or sizes of the device or its components, and / Or does not define or limit the scope of the exemplary embodiments.

Although specific terms are used in the following description for clarity, these terms are intended to indicate only specific configurations to the embodiments selected for illustration in the figure. , Is not intended to define or limit the scope of this disclosure. In the attached figure and the description below, each numeric display should be understood to indicate a component having similar functions.

The singular forms of "a," "an," and "the" include a plurality of referents, unless otherwise explicitly indicated.

As used in the specification and claims, the term "comprising" may include "consisting of" and "consisting essentially of" embodiments. The terms "comprise", "include", "having", "has", "can", "contin", and variants thereof , As used herein, intended to be an open-ended transition, term, or word that requires the presence of a designated component / step and allows the presence of other components / steps. do. However, the description of the composition or process, such as "consisting of" and "consisting essentially of" listed components / steps, is a designated component / step. Should be construed as allowing only the presence of possible impurities and excluding other components / steps.

The numbers in the specification and claims of the present application are the same as those shown in the present application for determining the values, as well as the numbers that are the same when rounded to the same number of significant figures. It should be understood that it contains a numerical value smaller than the experimental error in the conventional measurement method of.

All ranges disclosed herein include the indicated endpoints and can be combined independently (eg, the range "2 grams to 10 grams" includes endpoints 2 grams and 10 grams. , And all of the values between them).

The term "about" can be used to include any numerical value that can vary without changing the basic function of the value. When used with a range, "about" also discloses a range defined by the absolute value of the two endpoints, for example, "about 2 to about 4" also discloses a range of "2 to 4". .. The term "about" can refer to ± 10% of the numbers shown.

The present disclosure relates to couplings made from spinodal reinforced copper alloys. The copper alloys of the present disclosure can be copper-nickel-tin alloys having a combination of strength, ductility, high strain rate fracture toughness, and galling protection. More specifically, the couplings are envisioned to be artificial lift couplings, soccer rod couplings, or sub-couplings, which are used in the oil and gas industry in particular for hydrocarbon recovery systems.

In particular, the soccer couplings of the present disclosure are expected to be used to join an underground pump to a soccer rod string. A typical underground pump has a plunger that is reciprocated inside the pump tube by a soccer rod string. The plunger and cylinder include a standing valve and a traveling valve. The plunger is connected to the pump drive rod or valve rod, which is then connected to the valve rod bushing, which is connected to the soccer rod string through the soccer coupling.

The soccer coupling 130 according to the present disclosure is illustrated in FIG. Soccer rod couplings are used to assemble various components of a soccer rod string. For example, the soccer coupling 130 can be used to couple the soccer rod 210 and the valve rod bushing 220 as shown in FIGS. 3A and 3B and as described below.

The soccer coupling 130 itself is a core 132 having a first end 134, a central portion 170, and a second end 136, each end corresponding to a box and another within the soccer rod string. It has female threads (ie, female connectors) 138, 140 for engaging the pins of its components. The core has a substantially cylindrical shape and the length exceeds the diameter. Dotted lines 172 and 174 indicate where the central portion 170 joins the first end 134 and the second end 136. The central portion 170 has an outer diameter of 175.

The first end 134 has a first end surface 135. The first end 134 has a linear taper extending inward towards the end surface 135. In other words, the first end 134 is chamfered. Alternatively, the first end surface 135 can be described as having a diameter 144 smaller than the diameter 175 of the central portion 170. The term "taper" here refers only to the diameter decreasing from the center to each end and does not require a change in diameter as would occur in any given fashion. Here, the taper is linear, i.e., straight.

The second end 136 has a second end surface 137. The second end 136 has a rounded edge 139, which transitions into the end surface 137. The second end surface 137 therefore has a diameter of 146, which is less than the diameter of 175 of the central portion 170 but exceeds the diameter of 144 of the first end surface 135. In certain embodiments, the second end surface diameter 146 is at least a quarter inch larger than the first end surface diameter 144. In some specific embodiments, the first end surface diameter 144 is 1.625 inches, the second end surface diameter 146 is about 1.9 inches, and the central diameter 175 is 2. It is an inch.

The bore 142 extends completely through the core from the first end 134 to the second end 136 along the vertical axis 160 of the core. Both female threads 138 and 140 are located on the surface of the bore. Here, both female threads have the same box thread size and are complementary to male threads on other components of the soccer rod string that can be coupled by the coupling 130.

As further shown in the cross-sectional view provided by FIG. 1, the soccer coupling 130 includes counterbores 152, 154 on each end surface 135, 137. In other words, the female thread does not extend to the end surface. The vertical axis is also indicated by line 160. The soccer coupling 130 has an outer surface 162 curved into a substantially smooth cylindrical shape between the end surfaces 134 and 136. In other words, the outer diameter remains constant along the length of the central portion 170. The outer diameter is then reduced at the rounded edges of the tapered first end 134 and the second end 136.

2A and 2B are side views illustrating engagement between two components of a soccer rod string using the couplings of the present disclosure. FIG. 2A is an exploded partial cross-sectional view showing a soccer or stabilizing rod 210 and a valve rod bushing 220 coupled together via a soccer coupling 130. 2A and 2B illustrate the use of a coupling with the geometry of the soccer coupling 130 described above and shown in FIG.

The soccer or stabilizing rod 210 includes a rod body 212 and two rod ends (only rod end 214 is shown). The rod end 214 is provided by a male thread pin (or male connector) 216, a shoulder 218 adapted to abut on the surface of the end of the coupling, and a tool for torque and tighten the stabilizing rod. Includes a drive head 219 that can be engaged. The valve rod bushing 220 includes a bushing body 222 and two bushing ends 224, 225. The valve rod bushing includes a male thread pin (or male connector) 226 at the first bushing end 224 and a counterbore 227 at the second bushing end 224. The shoulder portion 221 is located between the two bushing ends 224 and 225. The counterbore 227 has a female screw 228 (ie, a female connector) located on the surface of the counterbore to engage the pins of another component within the soccer rod string. A drive head 229 is also included, which can be engaged by a tool for torque and tighten the valve rod bushing.

FIG. 2B shows the components of FIG. 2A in assembled form. That is, the male connector of the stabilizing rod 210 is fitted with the female connector at the second end of the soccer rod coupling 130, and the male connector of the valve rod bushing 220 is the first of the soccer rod coupling 130. Fitted with a female connector at the end. FIG. 2B illustrates that the outer diameter of the coupling can exceed the outer diameter of the rod string component to which the coupling such as the stabilizing rod 210 and the valve rod bushing 220 is attached. This prevents the combined rod string component from coming into contact with the production tubes surrounding the rod string (ie, conduit 411 in FIG. 4). In addition, the valve rod bushing and the end of the stabilizing rod are screwed into the coupling until the coupling abuts on the shoulders 218 and 221.

Additional modifications of the soccer coupling 330 according to the present disclosure are shown in FIGS. 3A and 3B. FIG. 3A is a photograph of a soccer coupling 330 for assembling various components of a soccer rod string. FIG. 3B is a cross-sectional view of the soccer rod coupling 330 taken in FIG. 3A.

Here, the soccer coupling 330 itself is a core 332 having a first end 334, a central portion 370, and a second end 336, each end corresponding to a box and a soccer rod string. It has female threads (ie, female connectors) 338, 340 for engaging the pins of another component within. The core has a substantially cylindrical shape and the length exceeds the diameter. Dotted lines 372 and 374 indicate where the central portion 370 joins the first end 334 and the second end 336. The central portion 370 has an outer diameter of 375.

The first end 334 has a first end surface 335. The first end 334 has a linear taper extending inward towards the end surface 335. In other words, the first end 334 is chamfered. Alternatively, the first end surface 335 can be described as having a diameter 344 smaller than the diameter 375 of the central portion 370.

The second end 336 has a second end surface 337. The second end 336 also has a linear taper extending inward towards the end surface 337. In other words, the second end 336 is also chamfered. Alternatively, the second end surface 337 can be described as having a diameter 346 smaller than the diameter 375 of the central portion 370. In a specific embodiment, the first end surface diameter 344 is approximately identical to the second end surface diameter 346, both having a central portion outer diameter of less than 375. In some specific embodiments, each of the first end surface diameter 344 and the second end surface diameter 346 is 1.625 inches and the central diameter 375 is 2 inches.

As illustrated here, the bore 342 extends completely along the vertical axis of the core from the first end 334 to the second end 336 through the core. Both female threads 338 and 340 are located on the surface of the bore. Here, both female threads have the same box thread size and are complementary to male threads on other components of the soccer rod string that can be coupled by the coupling 330. The dimensions of the various parts of the soccer rod and the soccer rod coupling are defined by API Specification 11B (27th edition) published in May 2010.

As further shown in the cross-sectional view provided by FIG. 3B, the soccer coupling 330 includes counterbores 352, 354 at each end surface 335, 337. In other words, the female thread does not extend to the end surface. The vertical axis is also indicated by line 360. The soccer coupling 330 has an outer surface 362 curved in a substantially smooth cylindrical shape along the central portion 370 of the coupling. The outer diameter is then reduced at the chamfered end portions 334, 336. The central outer diameter of these couplings can be greater than the outer diameter of the rod string component to which the coupling is attached, such as a stabilizing rod or valve rod bushing. This prevents the rod string component to be coupled from coming into contact with the production pipes surrounding the rod string (ie, conduit 411 in FIG. 4).

FIG. 4 illustrates various components of the pump system 400 utilizing the various rod string components described above such as soccer couplings. The system 400 has a moving beam 422 that reciprocates a rod string 424 including a polished rod portion 425. The rod string 224 is suspended from the beam to operate the underground pump 426 located at the bottom of the well 428.

The moving beam 422 is then actuated by a pitman arm, the pitman arm is reciprocated by a crank arm 430 driven by a power source 432 (eg, an electric motor), the power source 432 is a gearbox 434, etc. It is coupled to the crank arm 430 through the gear reduction mechanism of. The power source can be a three-phase AC induction motor or a synchronous motor and is used to drive the pumping unit. The gearbox 434 converts the motor torque into a low speed but high torque output to drive the crank arm 430. The crank arm 430 comprises a counterweight 436 that serves to keep the rod string 424 suspended from the beam 422. Balancing can also be provided by pneumatic cylinders such as those found in air equilibrium units. The belt type pumping unit may use a rod stroke or a counterweight extending in the opposite direction of the pneumatic cylinder for the counterweight.

The underground pump 426 may be a reciprocating type pump having a plunger 438 attached to the end of the rod string 424 and a pump cylinder 440 attached to the end of the pipes of the well 428. The plunger 438 includes a traveling valve 442 located at the bottom of the cylinder 440 and a standing valve 444. During the pump upstroke, the traveling valve 442 closes, lifting fluids such as oil and / or water above the plunger 438 to the top of the well, the standing valve 444 opens and additional fluid from the reservoir Allows fluid to flow into the pump tube 440. During the downstroke, the traveling valve 442 opens and the standing valve 444 closes to prepare for the next cycle. The operation of the pump 426 is controlled such that the fluid level maintained within the pump cylinder 440 is sufficient to keep the lower end of the rod string 424 in the fluid throughout its stroke. The rod string 424 is surrounded by a conduit 411, which is then surrounded by a well casing 410. The rod string 424 below the polished rod portion 425 is made from a soccer or stabilizing rod 446 held together by a coupling 448. The coupling 448 may include the soccer coupling described above (eg 130, 230) and a valve rod bushing (eg 320).

The connection between the soccer rod and the valve rod bushing is one of the most problematic joints in the soccer rod string. Traditional coupling geometry and materials cause high speed tubing wear, which causes the well fluid to exit the pump, with the production tubing and the coupling between the valve rod bushing and the stabilizing rod. Due to the contact between the surfaces combined with the high speed of the well fluid as it flows through the gaps between. The use of copper alloys disclosed herein as materials for the couplings of the present disclosure reduces damage to threaded connections due to galling type wear between the coupling and the tubing. In addition, the geometry of the couplings of the present disclosure (eg, chamfered or rounded ends, large outer diameter) is a high energy contact between the coupling and the inner diameter of the tube due to misalignment. To prevent. That is, conventional couplings include sharp edges, which are likely to damage components in the case of high energy contact. In addition, the geometry of the couplings disclosed in the present disclosure facilitates the flow of well fluid into the gap along the diameter between the coupling and the pipes.

In addition, the couplings of the present disclosure made from the copper alloys disclosed herein allow the coupling to serve as a damping device. Damping is possible because the copper alloys disclosed herein have a low modulus of elasticity compared to conventional materials. Damping allows more energy to be absorbed when the lower surface of the valve rod bushing (eg, the bushing end 325 in FIG. 3A) collides with other components of the soccer rod string during the downward stroke of the pump. do. This phenomenon reduces the tendency of the mating surfaces of the upper components of the pump to be extremely cold-worked during operation. Such cold working not only leads to loss of ductility, ultimately cracks, but also to the formation of "extruded" metal protrusions that extend outward beyond the diameter at the time of installation of these components. Can also be connected. These protrusions damage the inner diameter of pipes and pump production tubes. Metal fragments can be generated as the protrusions crush. These fragments can cause serious damage to the working surface of pumps and tubing as they remain in the system. The high drag coefficient of the copper alloy disclosed herein allows the coupling to perform this damping function without plastic deformation. Rather, the coupling is capable of returning to its original dimensions after both compression during the downstroke and pulling during the upstroke. In other words, the coupling acts as a solid spring.

In general, the copper alloys used to form the couplings of the present disclosure have been cold-worked prior to being reheated and affecting the spinodal decomposition of the microstructure. Cold working is the process of mechanically modifying the shape or size of a metal by plastic deformation. This can be done by rolling, drawing, pressing, spinning, extrusion, or forging of metal or alloy. When a metal is plastically deformed, atomic dislocations occur within the material. In particular, dislocations occur across or within metal particles. The dislocations overlap each other and the dislocation density in the material increases. The increase in overlapping dislocations makes the transfer of further dislocations more difficult. This generally increases the hardness and tensile strength of the resulting alloy while reducing the ductility and impact properties of the alloy. Cold working also improves the surface finish of the alloy. Mechanical cold working is generally performed at a temperature below the recrystallization point of the alloy and is usually performed at room temperature.

Spinodal decomposition is a mechanism by which various components can be separated into specific regions or microstructures with different chemical compositions and physical properties. In particular, crystals having a bulk composition in the central region of the phase diagram cause dissolution. Spinodal decomposition that occurs on the surface of the alloys of the present disclosure results in surface hardening.

The structure of a spinodal alloy is made up of a structure made up of a homogeneous two-phase mixture when the initial phase separates at a certain temperature and a composition called a solubility gap that reaches a high temperature is produced. These alloy phases naturally decompose into another phase in which the atoms in the structure have changed while maintaining the same size while having the same crystal structure. Spinodal hardening increases the yield strength of the base metal and includes high uniformity of composition and microstructure.

Spinodal alloys most often show anomalies called solubility gaps in their phase diagrams. Within the relatively narrow temperature range of the solubility gap, atomic regularity occurs within the existing crystal lattice structure. The resulting two-phase structure stabilizes at temperatures well below the gap.

The copper-nickel-tin alloys used herein generally include about 9.0% by weight to about 15.5% by weight of nickel and about 6.0% by weight to about 9.0% by weight of tin. Including, the balance is copper. This alloy is curable and can be easily molded into high yield strength products that can be used in a variety of industrial and commercial applications. This high performance alloy is designed to provide properties similar to copper-beryllium alloys.

More specifically, the copper-nickel-tin alloys of the present disclosure contain from about 9% to about 15% by weight of nickel and from about 6% to about 9% by weight of tin, with the balance being copper. be. In a more specific embodiment, the copper-nickel-tin alloy comprises from about 14.5% by weight to about 15.5% by weight of nickel and from about 7.5% by weight to about 8.5% by weight of tin. The rest is copper.

The ternary copper-nickel-tin spinodal alloy exhibits a beneficial combination of properties such as high strength, excellent tribological properties, and high corrosion resistance in sea and acid environments. The increase in yield strength of base metals can result from spinodal decomposition in copper-nickel-tin alloys.

Copper alloys may include beryllium, nickel, and / or cobalt. In some embodiments, the copper alloy comprises from about 1 to about 5% by weight beryllium, and the total of cobalt and nickel is in the range of about 0.7 to about 6% by weight. In a specific embodiment, the alloy comprises about 2% by weight beryllium and about 0.3% by weight cobalt and nickel. Other copper alloy embodiments can include a range of about 5-7% by weight beryllium.

In some embodiments, the copper alloy comprises chromium. Chromium can be present as an alloy in an amount of less than about 5% by weight containing about 0.5% by weight to about 2.0% by weight or about 0.6% by weight to about 1.2% by weight of chromium.

In some embodiments, the copper alloy comprises silicon. Silicon may be present in an amount of less than 5% by weight containing from about 1.0% by weight to about 3.0% by weight or from about 1.5% to about 2.5% by weight of silicon.

The alloys of the present disclosure optionally include small amounts of additives such as iron, magnesium, manganese, molybdenum, niobium, tantalum, vanadium, zirconium, and mixtures thereof. The additive may be present in an amount of up to 1% by weight, preferably up to 0.5% by weight. In addition, small amounts of natural impurities may be present. Small amounts of other additives such as aluminum and zinc may also be present. The presence of additional elements may have the effect of further increasing the strength of the resulting alloy.

In some embodiments, an amount of magnesium is added during the formation of the initial alloy to reduce the oxygen content of the alloy. Magnesium oxide is formed so that it can be removed from the alloy mass.

In certain embodiments, the female threads of the coupling are formed by rolling, not by cutting. This process is thought to stretch the particles on the outer surface of the thread. Rolled threads have been found to resist desquamation because shear breakage occurs across the particles rather than with them. This cold working process provides additional strength and fatigue resistance. As a result, the female thread may have a Rockwell C hardness (HRC) of about 20 to about 40. The HRC can vary throughout the thread and this detail should not be construed as requiring the entire thread to have the same HRC. In certain embodiments, the thread HRC is a minimum of 22. The outer surface of the thread may have at least 35 HRCs.

The alloys used to make the couplings of the present disclosure may have a 0.2% offset yield strength of at least 75 ksi, including at least 85 ksi, or at least 90 ksi, or at least 95 ksi.

The alloys used to make the couplings of the present disclosure may have a combination of 0.2% offset yield strength and room temperature Charpy V notch impact energy, as shown in Table 1 below. These combinations are unique to the copper alloys of the present disclosure. The test samples used to make these measurements were oriented vertically. The listed values are the minimum values (ie, at least the listed values), preferably the offset yield strength and the Charpy V-notch impact energy values are higher than the combinations listed here. In other words, the alloy has a combination of 0.2% offset yield strength above the values listed here and room temperature Charpy V notch impact energy.

Table 2 provides the properties of another exemplary embodiment of copper-based alloys suitable for use in soccer rod couplings or sub-couplings.

0.2% offset yield strength and maximum tensile strength were measured according to ASTME8. CVN toughness was measured according to ASTME23. The rod couplings of the present disclosure can be made using casting and / or molding techniques known in the art.

Couplings made from spinodal decomposition copper alloys have unique high tensile strength and fatigue strength in combination with high fracture toughness, galling resistance, and corrosion resistance. The unique combination of properties allows the coupling to meet the required basic mechanical and corrosive properties while ensuring that the system components are protected from galling damage, thereby significantly extending the life of the system. To reduce the risk of unexpected failures. One result is a longer well life between maintenance outages for maintenance. In addition, overall production is also improved due to the reduced friction.

Some copper-nickel-tin alloys of the present disclosure have a low coefficient of friction. In some embodiments, the copper-nickel-tin alloy in contact with carbon steel has a slip coefficient of friction of less than 0.4. In other embodiments, the copper-nickel-tin alloy has a slip coefficient of about 0.3 or less, including about 0.2 or less.

In certain embodiments of the present disclosure, copper-nickel-tin alloys in contact with carbon steel typically have a slip coefficient of less than 0.2 (including about 0.175 or less). In contrast, nickel alloys in contact with carbon steel typically have a coefficient of friction of 0.7. Carbon steel in contact with carbon steel typically has a slip coefficient of 0.6, and aluminum bronze in contact with carbon steel typically has a slip coefficient of 0.4. A comparison of these values is illustrated in the graph of FIG. Therefore, it is possible to significantly reduce the overall friction loss in the pumping system.

The reduction in friction also results in low tube wear. FIG. 6 is a graph showing the use of three different metals used in bearings that come into contact with a carburized steel shaft with average bearing stress at 2,000 psi and vibrating axial motion due to lateral loads. The y-axis indicates the change in clearance due to wear, and lower values indicate low wear. As can be seen here, the copper-nickel-tin alloy was less worn than aluminum bronze (square, 0.015-0.020 inch) and hardened steel (diamond, above 0.045 inch) (triangle, Less than 0.010 inches).

The following examples are provided to illustrate the couplings, processes, and characteristics of the present disclosure. These examples are for illustration purposes only and are not intended to limit this disclosure to the materials, conditions, or process parameters described therein.
(Example)
(Example 1)

Soccer rod couplings made from Cu-15Ni-8Sn alloy were used on rod strings in selected test wells with L80 carbon steel production tubes (HRC22-23 hardness). Mean time between failures (MTBF) for steel couplings was about 10 months. When the Cu15Ni8Sn coupling was installed, MTBF increased 5-fold. No evidence of wear or gold transfer was found in the Cu15Ni8Sn couplings inspected.

One well was shut down 555 days after the Cu15Ni8Sn coupling was installed due to a pump leak. The pipes used to form the well casing were also inspected. 50% of tubing with steel couplings had ≧ 30% wall loss, while 0% of tubing with Cu15Ni8Sn couplings had ≧ 30% wall loss. Twenty-five percent of tubes with steel couplings had ≧ 30% surface pitting, while 0% of tubing with Cu15Ni8Sn couplings had ≧ 30% surface pitting. It was calculated that this would increase the MTBF of the tube by at least 3-fold.
(Example 2)

A 55Cu15Ni8Sn coupling was installed at the bottom of the well at 1,400 feet. The following information was captured.

The result of using the Cu15Ni8Sn coupling was a 6.4% increase in liquid production. Results for similar experiments showed a 9% increase in production, a 12% maximum load reduction, and a 21% increased pump stroke.
Thus, a pump stroke increase of about 3% to up to about 40%, or about 6% to about 40%, or about 6% to about 30%, or about 3% to about 10%, or about 6% to about 10%. Is expected to result from the use of these copper-nickel-tin alloys (compared to the use of steel).
(Example 3)

The coupling was made from Cu15Ni8Sn alloy. The coupling is depicted in FIG. 7 and has a cross section as illustrated in FIG. 3B. The tapered coupling has a 2 inch outer diameter with a 3/4 inch rolled screw. The coupling is joined to the valve rod bushing and acts as a centralizer so that the valve rod bushing does not wear adjacent pipes.

It will be appreciated that variants of the above disclosure, other features and functions, or alternatives thereof, can be combined into many other systems and applications. Various alternatives, changes, modifications, or improvements that are currently unpredictable or unpredictable may be made by those skilled in the art in the future, which are also intended to be included in the appended claims.
Specific embodiments of the present invention are as follows.
[Aspect 1]
It is a soccer rod string, and the soccer rod string is
A soccer rod, including an end with a pin with a male screw,
A valve rod bushing comprising an end having a pin with a male thread, wherein the valve rod bushing is a valve rod bushing that is connected to an underground pump.
With a coupling that has a core
Equipped with
The core has a first end, a central portion, and a second end, each of the first end and the second end having an end surface, said. The first end is linearly inwardly tapered from the center to the surface of the first end, the coupling is made of a spinodal-hardened copper-nickel-tin alloy, the alloy of which is: When measured against carbon steel, it has a coefficient of friction of less than 0.4 and a threaded bore extends through the core from the first end to the second end. ,
The threaded bore at the first end of the coupling is complementary to the male thread of the valve rod bushing, and the threaded bore at the second end of the coupling is said. A soccer rod string that is complementary to the male thread of the soccer rod.
[Aspect 2]
The second end surface has rounded edges, or the second end is tapered inward linearly from the center to the second end surface. The soccer rod string according to the first aspect.
[Aspect 3]
The soccer rod string according to aspect 1, wherein the outer diameter of the soccer rod is larger than the outer diameter of the valve rod bushing.
[Aspect 4]
The soccer rod string according to aspect 1, wherein the outer diameter of the coupling is larger than both the outer diameter of the soccer rod and the outer diameter of the valve rod bushing.
[Aspect 5]
The soccer rod string according to aspect 1, wherein the surface of the first end abuts on the shoulder portion of the valve rod bushing.
[Aspect 6]
The soccer rod string according to aspect 1, wherein the surface of the second end abuts on the shoulder portion of the soccer rod.
[Aspect 7]
The alloy comprises from about 8 to about 20% by weight nickel and from about 5 to about 11% by weight tin, with the balance being copper and the alloy having a 0.2% offset yield strength of at least 75 ksi. The soccer rod string according to the first aspect.
[Aspect 8]
The football according to aspect 1, wherein the alloy comprises from about 14.5% by weight to about 15.5% by weight nickel and from about 7.5% by weight to about 8.5% tin, with the balance being copper. Rod string.
[Aspect 9]
The soccer rod string according to aspect 1, wherein the alloy has a 0.2% offset yield strength of at least 95 ksi and a Charpy V-notch impact energy of at least 22 ft-lbs at room temperature.
[Aspect 10]
A coupling for a soccer rod string,
The coupling comprises a core, the core having a first end, a central portion, and a second end, each of the first end and the second end. , Has an edge surface,
(A) The first end portion is linearly tapered inward from the central portion to the surface of the first end portion, and (B) (i) the surface of the second end portion is rounded. Either it has an edge or (ii) the second end is linearly inwardly tapered from the center to the surface of the second end.
The coupling is made from a spinodal-hardened copper-nickel-tin alloy and has a coefficient of friction of less than 0.4 when measured against carbon steel.
[Aspect 11]
The coupling according to aspect 10, wherein the diameter of the first end surface is smaller than the diameter of the second end surface.
[Aspect 12]
10. The coupling according to aspect 10, further comprising a threaded bore extending entirely from the first end to the second end through the core.
[Aspect 13]
The coupling according to aspect 12, wherein the thread of the bore has a Rockwell C hardness (HRC) of about 20 to about 40.
[Aspect 14]
The coupling according to aspect 10, wherein each of the first end and the second end also includes a counterbore.
[Aspect 15]
The alloy comprises from about 8 to about 20% by weight nickel and from about 5 to about 11% by weight tin, with the balance being copper and the alloy having a 0.2% offset yield strength of at least 75 ksi. The coupling according to aspect 10.
[Aspect 16]
The cup of aspect 10, wherein the alloy comprises from about 14.5% by weight to about 15.5% by weight nickel and from about 7.5% to about 8.5% tin, with the balance being copper. ring.
[Aspect 17]
The coupling according to aspect 10, wherein the alloy has a 0.2% offset yield strength of at least 85 ksi.
[Aspect 18]
10. The coupling according to aspect 10, wherein the alloy has a 0.2% offset yield strength of at least 95 ksi and a Charpy V-notch impact energy of at least 22 ft lbs at room temperature.
[Aspect 19]
It is a method of extracting a fluid from a well, and the above method is
Using a soccer rod string to operably connect the underground pump to the motor,
Using the soccer rod string to operate the underground pump to extract fluid from the well.
Including
The underground pump includes a valve rod bushing and
The soccer coupling connects the valve rod bushing to the soccer rod string and
The soccer coupling is
Each of the first end and the second end has an end surface, comprising a core having a first end, a center, and a second end.
(A) The first end portion is linearly tapered inward from the central portion to the surface of the first end portion, and (B) (i) the surface of the second end portion is rounded. Either it has an edge or (ii) the second end is linearly inwardly tapered from the center to the surface of the second end.
The method, wherein the coupling is made from a spinodal-hardened copper-nickel-tin alloy and has a coefficient of friction of less than 0.4 when measured against carbon steel.
[Aspect 20]
19. The method of aspect 19, wherein the mean time between failures (MTBF) of the soccer coupling is at least four times greater than the MTBF of a coupling made of L80 carbon steel.
[Aspect 21]
It is a pump system, and the pump system is
Underground pump and
A power source for supplying power to the underground pump and
With a rod string located between the underground pump and the power source
Equipped with
The rod string is
A soccer rod, including an end with a pin with a male screw,
A valve rod bushing comprising an end having a pin with a male thread, wherein the valve rod bushing is a valve rod bushing that is connected to the underground pump.
With a coupling that has a core
Equipped with
The core has a first end, a central portion, and a second end, each of the first end and the second end having an end surface, said. The first end is linearly inwardly tapered from the central portion to the surface of the first end, and (i) the surface of the second end has a rounded edge or is , (Ii) either the second end is linearly inwardly tapered from the center to the surface of the second end, and the coupling is a spinodal hardened copper-nickel-. Made from tin alloy and measured against carbon steel, it has a coefficient of friction of less than 0.4 and a threaded bore through the core from the first end to the second end. Has grown to the whole,
The threaded bore at the first end of the coupling is complementary to the male thread of the valve rod bushing, and the threaded bore at the second end of the coupling is said. A pump system that is complementary to the male thread of the stabilizing rod.

Claims (21)

It is a soccer rod string, and the soccer rod string is
A soccer rod, including an end with a pin with a male screw,
A valve rod bushing comprising an end having a pin with a male thread, wherein the valve rod bushing is a valve rod bushing that is connected to an underground pump.
With a coupling that has a core,
The core has a first end, a central portion, and a second end, each of the first end and the second end having an end surface, said. The first end is linearly inwardly tapered from the center to the surface of the first end, the coupling is made of a spinodal-hardened copper-nickel-tin alloy, the alloy of which is: When measured against carbon steel, it has a coefficient of friction of less than 0.4 and a threaded bore extends through the core from the first end to the second end. ,
The threaded bore at the first end of the coupling is complementary to the male thread of the valve rod bushing, and the threaded bore at the second end of the coupling is said. A soccer rod string that is complementary to the male thread of the soccer rod. The second end surface has rounded edges, or the second end is tapered inward linearly from the central portion to the second end surface. The soccer rod string according to claim 1. The soccer rod string according to claim 1, wherein the outer diameter of the soccer rod is larger than the outer diameter of the valve rod bushing. The soccer rod string according to claim 1, wherein the outer diameter of the coupling is larger than both the outer diameter of the soccer rod and the outer diameter of the valve rod bushing. The soccer rod string according to claim 1, wherein the surface of the first end abuts on the shoulder portion of the valve rod bushing. The soccer rod string according to claim 1, wherein the surface of the second end abuts on the shoulder portion of the soccer rod. The alloy comprises from about 8 to about 20% by weight nickel and from about 5 to about 11% by weight tin, with the balance being copper and the alloy having a 0.2% offset yield strength of at least 75 ksi. The soccer rod string according to claim 1. The alloy according to claim 1, wherein the alloy comprises from about 14.5% by weight to about 15.5% by weight nickel and from about 7.5% by weight to about 8.5% tin, with the balance being copper. Soccer rod string. The soccer rod string of claim 1, wherein the alloy has a 0.2% offset yield strength of at least 95 ksi and a Charpy V-notch impact energy of at least 22 ft-lbs at room temperature. A coupling for a soccer rod string,
The coupling comprises a core, the core having a first end, a central portion, and a second end, each of the first end and the second end. , Has an edge surface,
(A) The first end portion is linearly tapered inward from the central portion to the surface of the first end portion, and (B) (i) the surface of the second end portion is rounded. Either it has an edge or (ii) the second end is linearly inwardly tapered from the center to the surface of the second end.
The coupling is made from a spinodal-hardened copper-nickel-tin alloy and has a coefficient of friction of less than 0.4 when measured against carbon steel. The coupling according to claim 10, wherein the diameter of the first end surface is smaller than the diameter of the second end surface. 10. The coupling of claim 10, further comprising a threaded bore extending entirely from the first end to the second end through the core. 12. The coupling of claim 12, wherein the thread of the bore has a Rockwell C hardness (HRC) of about 20 to about 40. 10. The coupling of claim 10, wherein each of the first end and the second end also includes a counterbore. The alloy comprises from about 8 to about 20% by weight nickel and from about 5 to about 11% by weight tin, with the balance being copper and the alloy having a 0.2% offset yield strength of at least 75 ksi. The coupling according to claim 10. 10. The alloy according to claim 10, wherein the alloy comprises from about 14.5% by weight to about 15.5% by weight nickel and from about 7.5% by weight to about 8.5% tin, with the balance being copper. Coupling. 10. The coupling of claim 10, wherein the alloy has a 0.2% offset yield strength of at least 85 ksi. 10. The coupling of claim 10, wherein the alloy has a 0.2% offset yield strength of at least 95 ksi and a Charpy V-notch impact energy of at least 22 ft-lbs at room temperature. It is a method of extracting a fluid from a well, and the above method is
Using a soccer rod string to operably connect the underground pump to the motor,
The soccer rod string is used to operate the underground pump to extract fluid from the well.
The underground pump includes a valve rod bushing and
The soccer coupling connects the valve rod bushing to the soccer rod string and
The soccer coupling is
Each of the first end and the second end has an end surface, comprising a core having a first end, a center, and a second end.
(A) The first end portion is linearly tapered inward from the central portion to the surface of the first end portion, and (B) (i) the surface of the second end portion is rounded. Either it has an edge or (ii) the second end is linearly inwardly tapered from the center to the surface of the second end.
The method, wherein the coupling is made from a spinodal-hardened copper-nickel-tin alloy and has a coefficient of friction of less than 0.4 when measured against carbon steel. 19. The method of claim 19, wherein the mean time between failures (MTBF) of the soccer coupling is at least four times greater than the MTBF of a coupling made of L80 carbon steel. It is a pump system, and the pump system is
Underground pump and
A power source for supplying power to the underground pump and
It is equipped with a rod string located between the underground pump and the power source.
The rod string is
A soccer rod, including an end with a pin with a male screw,
A valve rod bushing comprising an end having a pin with a male thread, wherein the valve rod bushing is a valve rod bushing that is connected to the underground pump.
With a coupling that has a core,
The core has a first end, a central portion, and a second end, each of the first end and the second end having an end surface, said. The first end is linearly inwardly tapered from the central portion to the surface of the first end, and (i) the surface of the second end has a rounded edge or is , (Ii) either the second end is linearly inwardly tapered from the center to the surface of the second end, and the coupling is a spinodal hardened copper-nickel-. Made from tin alloy and measured against carbon steel, it has a coefficient of friction of less than 0.4 and a threaded bore through the core from the first end to the second end. Has grown to the whole,
The threaded bore at the first end of the coupling is complementary to the male thread of the valve rod bushing, and the threaded bore at the second end of the coupling is said. A pump system that is complementary to the male thread of the soccer rod.

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