Couplings for well pumping components

Patent metadata

Field	Value
Publication number	US-2018266190-A1
Application number	US-201815926784-A
Country	US
Kind code	A1
Filing date	Mar 20, 2018
Priority date	Jun 5, 2014
Publication date	Sep 20, 2018
Grant date	—

Abstract

A coupling for joining a downhole pump to a sucker rod string is disclosed. The coupling includes a core having a first end, a central portion, and a second end. The first end and the second end each have an end surface. The first end tapers linearly inwards from the central portion to the first end surface. The second end has a rounded edge along the second end surface. The coupling is made from a spinodally-hardened copper-nickel-tin alloy and has a sliding coefficient of friction of less than 0.4 when measured against carbon steel.

First claim

1 . A sucker rod string, comprising:
a sucker rod including an end having a pin with an external thread; a valve rod bushing including an end having a pin with an external thread, wherein the valve rod bushing connects to a downhole pump; and a coupling comprising a core having a first end, a central portion, and a second end, the first end and the second end each having an end surface, wherein the first end tapers linearly inwards from the central portion to the first end surface; and wherein the coupling is made from a spinodally-hardened copper-nickel-tin alloy that has a sliding coefficient of friction of less than 0.4 when measured against carbon steel, and wherein a threaded bore runs entirely through the core from the first end to the second end; wherein the threaded bore at the first end of the coupling is complementary with the external thread of the valve rod bushing, and the threaded bore at the second end of the coupling is complementary with the external thread of the sucker rod.

2 . The sucker rod string of claim 1 , wherein the second end surface has a rounded edge, or wherein the second end tapers linearly inwards from the central portion to the second end surface.

3 . The sucker rod string of claim 1 , wherein an outer diameter of the sucker rod is greater than an outer diameter of the valve rod bushing.

4 . The sucker rod string of claim 1 , wherein an outer diameter of the coupling is greater than both an outer diameter of the sucker rod and an outer diameter of the valve rod bushing.

5 . The sucker rod string of claim 1 , wherein the first end surface abuts a shoulder portion of the valve rod bushing.

6 . The sucker rod string of claim 1 , wherein the second end surface abuts a shoulder portion of the sucker rod.

7 . The sucker rod string of claim 1 , wherein the alloy comprises from about 8 to about 20 wt % nickel, and from about 5 to about 11 wt % tin, the remaining balance being copper, wherein the alloy has a 0.2% offset yield strength of at least 75 ksi.

8 . The sucker rod string of claim 1 , wherein the alloy comprises about 14.5 wt % to about 15.5 wt % nickel, and about 7.5 wt % to about 8.5% tin, the remaining balance being copper.

9 . The sucker 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.

10 . A coupling for a sucker rod string, comprising:
a core having a first end, a central portion, and a second end, the first end and the second end each having an end surface, wherein (A) the first end tapers linearly inwards from the central portion to the first end surface, and (B) either (i) the second end surface has a rounded edge or (ii) the second end tapers linearly inwards from the central portion to the second end surface; and wherein the coupling is made from a spinodally-hardened copper-nickel-tin alloy and has a sliding coefficient of friction of less than 0.4 when measured against carbon steel.

11 . The coupling of claim 10 , wherein a diameter of the first end surface is less than a diameter of the second end surface.

12 . The coupling of claim 10 , further comprising a threaded bore running entirely through the core from the first end to the second end.

13 . The coupling of claim 12 , wherein the threads of the bore have a Rockwell C hardness (HRC) of about 20 to about 40.

14 . The coupling of claim 10 , where the first end and the second end each also includes a counterbore.

15 . The coupling of claim 10 , wherein the alloy comprises from about 8 to about 20 wt % nickel, and from about 5 to about 11 wt % tin, the remaining balance being copper, wherein the alloy has a 0.2% offset yield strength of at least 75 ksi.

16 . The coupling of claim 10 , wherein the alloy comprises about 14.5 wt % to about 15.5 wt % nickel, and about 7.5 wt % to about 8.5% tin, the remaining balance being copper.

17 . The coupling of claim 10 , wherein the alloy has a 0.2% offset yield strength of at least 85 ksi.

18 . 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.

19 . A method of extracting a fluid from a well, comprising:
operatively connecting a downhole pump to a motor using a sucker rod string; and operating the downhole pump using the sucker rod string to extract fluid from the well wherein the downhole pump includes a valve rod bushing; wherein a sucker coupling connects the valve rod bushing to the sucker rod string; and wherein the sucker coupling comprises:
a core having a first end, a central portion, and a second end, the first end and the second end each having an end surface,
wherein (A) the first end tapers linearly inwards from the central portion to the first end surface, and (B) either (i) the second end surface has a rounded edge or (ii) the second end tapers linearly inwards from the central portion to the second end surface; and
wherein the coupling is made from a spinodally-hardened copper-nickel-tin alloy and has a sliding coefficient of friction of less than 0.4 when measured against carbon steel.

20 . The method of claim 19 , wherein a mean time between failure (MTBF) of the sucker coupling is at least four time greater than the MTBF of a coupling made from L80 carbon steel.

21 . A pump system comprising:
a downhole pump; a power source for powering the downhole pump; and a rod string located between the downhole pump and the power source; wherein the rod string comprises:
a sucker rod including an end having a pin with an external thread;
a valve rod bushing including an end having a pin with an external thread, the valve rod bushing being connected to the downhole pump;
a coupling comprising a core having a first end, a central portion, and a second end, the first end and the second end each having an end surface, wherein the first end tapers linearly inwards from the central portion to the first end surface, and either (i) the second end surface has a rounded edge or (ii) the second end tapers linearly inwards from the central portion to the second end surface; and wherein the coupling is made from a spinodally-hardened copper-nickel-tin alloy that has a sliding coefficient of friction of less than 0.4 when measured against carbon steel, and wherein a threaded bore runs entirely through the core from the first end to the second end;
wherein the threaded bore at the first end of the coupling is complementary with the external thread of the valve rod bushing, and the threaded bore at the second end of the coupling is complementary with the external thread of the stabilizer rod.

Assignees

• Materion Corp

Inventors

• Nielsen Jr William D
• Nielsen Diane M

Classifications

• E21B43/126

  Adaptations of down-hole pump systems powered by drives outside the borehole, e.g. by a rotary or oscillating drive (powered by fluid E21B43/129) · CPC title

• E21B17/042 Primary

  Threaded · CPC title

• E21B17/00

  Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; {Cables;} Casings; Tubings · CPC title

• C22C9/06

  with nickel or cobalt as the next major constituent · CPC title

• E21B17/0426 Primary

  with a threaded cylindrical portion, e.g. for percussion rods · CPC title