1. Alejandro F. Ameglio – Head Technical Services Tenaris Rods Division
26 November November 2018
Development and field experience of 7/8” with 1” pin sucker rods Use of UHS couplings
Alejandro F. Ameglio – Head Technical Services
Tenaris Rods Division

2. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods – UHS Couplings
26 November November 2018
Contents
7/8” with 1” pin sucker rods
Field statistics - History
Concept
Development
Field experiences
Field evolution
Conclusions
UHS Couplings
Concept
Derating factors
Technical Data
Field experience
Conclusions
7/8” with 1” sucker rods – UHS Couplings
26 November 2018

3. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
Introduction
This idea is a result of a team work between a major operating company from Argentina (Pan American Energy) and Tenaris
Pan American Energy operates Cerro Dragón Field (south of Argentina)
Field data
Total amount of producing wells: 2193 ( ft)
Total Production rate: 123 Mm3/d (774 Mbfpd)
Total oil rate: 13,7 Mm3/d (86,2 Mbfpd)
Total rod pumping wells: 1718
7/8” with 1” sucker rods – UHS Couplings
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4. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
Introduction
Rod pumping wells
Depths: 2193 ( ft)
Production rates: m3/d ( bfpd)
7/8” with 1” sucker rods – UHS Couplings
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5. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
Introduction
Due to a secondary recovery process started in 1988, fluid production rates have been continuously raising.
This increased the loads levels, and the failures rates at rod strings
7/8” with 1” sucker rods – UHS Couplings
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6. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
Field History
7/8” with 1” sucker rods – UHS Couplings
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7. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
Field History
7/8” with 1” sucker rods – UHS Couplings
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8. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
Field History
Main problem to solve
7/8” pin failures
7/8” with 1” sucker rods – UHS Couplings
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9. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
Concept - Ideas
7/8” with 1” sucker rods – UHS Couplings
26 November 2018

10. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
Analyzing the problem
As a first step, all the factors involved in the problem were analyzed
Make up practices
Training program applied / Control and Inspection at wellhead
Make-up torque control method
Use of displacement cards (API circumferential displacement method)
Pin pre-tension increment (new torque card)
Lab studies to determine the optimum circumferential displacement for Grade D rods
After all
7/8” pin failures rates still going up!!!
7/8” with 1” sucker rods – UHS Couplings
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11. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
Analyzing the problem
At second stage, different alternatives were evaluated
New threaded connection for sucker rods
Not easy. Long times of development required
Material’s resistance increasing
There were as much pin failures in HS rods as in Grade D
THE OIL MEN’S SOLUTION
MAKE IT BIGGER!!!
7/8” with 1” sucker rods – UHS Couplings
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12. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
Concept - Ideas
Solution
“The objective was to strenghten the cross section at the stress relief zone for the 7/8” rods”
Sucker Rod diameter (OD)
Rod body area (cross-section)
Rbody
Rod pin area (cross-section) at the stress relief
Rpin
Areas Ratio (Rpin / Rbody)
Inch
Inch2
0.44
0.66
1.5
7/8
0.60
0.85
1.4 1
0.79
1.18
7/8” with 1” sucker rods – UHS Couplings
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13. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
Concept - Ideas
HOW?
Making a 7/8” rod with 1” pin
Development of a new forging technique
For fatigue resistance, steel fibers must “copy” the external shape of the element
Cutted or whirled steel fibers result in a fatigue failure
7/8” with 1” sucker rods – UHS Couplings
26 November 2018

14. 7/8” with 1” pin rods – First attempts
7/8” with 1” pin sucker rods
26 November November 2018
7/8” with 1” pin rods – First attempts
7/8” with 1” sucker rods – UHS Couplings
26 November 2018

15. 7/8” with 1” pin rods – Forging process
7/8” with 1” pin sucker rods
26 November November 2018
7/8” with 1” pin rods – Forging process
7/8” with 1” sucker rods – UHS Couplings
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16. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
7/8” with 1” pin rods
Detail of a 7/8” with 1” pin sucker rod showing the steel fibers
7/8” with 1” sucker rods – UHS Couplings
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17. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
7/8” with 1” pin rods
Comparison between 7/8” API vs. 7/8” with 1” pin rods
7/8” with 1” sucker rods – UHS Couplings
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18. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
Field experience
Wells installed – First Lot of field tests
A first lot of /8” with 1” pin were installed
7/8” with 1” sucker rods – UHS Couplings
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19. Field experience – Well #A
7/8” with 1” pin sucker rods
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Field experience – Well #A
Well
Date
Cause of Intervention
Comments A
29/06/1982
Rod String Break
7/8” pin break
17/05/1986
22/07/1986
5/02/1987
16/07/1988
1/09/1991
10/01/1992
19/04/1993
6/04/1996
11/06/1998
7/10/1998
7/8” pin break – 7/8” with 1” pin INSTALLATION
14/11/2002
FIRST 7/8” WITH 1” PIN FAILURE
IPA (index) before the installation of 7/8” – 1” pin rods: 0.66
IPA (index) after the installation of 7/8” – 1” pin rods: 0.24
Average running time of conventional API 7/8” rods: 502 days
Running time of 7/8”-1” pin rods: 1499 days – 17 MM cycles
7/8” with 1” sucker rods – UHS Couplings
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20. Field experience – Well #B
7/8” with 1” pin sucker rods
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Field experience – Well #B
Well
Date
Cause of Intervention
Comments B
13/Oct/1995
Rod String Break
7/8” pin break
17/Dec/1996
23/Ago/1997
21/Oct/1998
7/8” pin break – 7/8” with 1” pin INSTALLATION
1/Jun/2003
FIRST 7/8” with 1” pin FAILURE
IPA (index) before the installation of 7/8” – 1” pin rods: 1.30
IPA (index) after the installation of 7/8” – 1” pin rods: 0.21
Average running time of conventional API 7/8” rods: 368 days
Running time of 7/8”-1” pin rods: 1684 days – 19 MM cycles
7/8” with 1” sucker rods – UHS Couplings
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21. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
26 November November 2018
Field experience
Wells installed – Second lot of field tests
7/8” with 1” sucker rods – UHS Couplings
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22. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
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Field evolution
7/8” with 1” sucker rods – UHS Couplings
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23. 7/8” with 1” sucker rods – UHS Couplings
7/8” with 1” pin sucker rods
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Conclusions
The new product, fruit of the teamwork between Pan American Energy and Tenaris, has largely overcome the most optimistic expectations.
A 30% reduction in the pin failures was achieved, considering the total amount of oil wells with rod pumping lift systems.
If we referred only to the wells that have this solution, we have reduced the IPA (index of intervention per well per year) approximately in five (5) times.
Today the use of these rods has became standard for all oil well deeper than 2000 mts and with high producing rates,
An increasing of 30% in the fatigue resistance capacity of this rods is only the first step. That conduct us to develop a new premium threaded connection applicable to all of the API conventional rods.
7/8” with 1” sucker rods – UHS Couplings
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24. 7/8” with 1” sucker rods – UHS Couplings
UHS Couplings (Ultra High Strength)
26 November November 2018
Introduction
Another problem to solve was the one related with failures in 1” SH (Slim Hole) couplings
This problem could be analyzed according with:
Use of 1” SH Class T couplings with Grade D rod strings
Use of 1” SH Class T couplings with HS (High Strenght) sucker rod strings
It is well known that SH (Slim Hole) couplings has to be affected by a derating factor in their allowable stress calculations
7/8” with 1” sucker rods – UHS Couplings
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25. Derating Factors for SH couplings
UHS Couplings (Ultra High Strength)
26 November November 2018
Derating Factors for SH couplings
According to Bradley (Petroleum Engineering Handbook) and Hermanson (LTV Energy), use of SH couplings requires the use of a derating factor that affect the max. allowable stress of the string
API SH Coupling Size
Derating Factors for Rod Grades in K C D HS
5/8” -
0.97
0.77
0.63
3/4”
0.86
0.70
7/8”
0.93
0.88
0.69
0.57 1”
0.89
0.74
7/8” with 1” sucker rods – UHS Couplings
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26. No derating factors required Increase the Couplings resistance
UHS Couplings (Ultra High Strength)
26 November November 2018
Analyzing the problem
Problem to solve:
1” API SH Couplings
failures
Possibility to use 1” API FS Couplings
No derating factors required
YES
Geometry problems
(Tubing 2 7/8”) NO
Increase the Couplings resistance
UHS Couplings
7/8” with 1” sucker rods – UHS Couplings
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27. 7/8” with 1” sucker rods – UHS Couplings
UHS Couplings (Ultra High Strength)
26 November November 2018
Technical Data
UHS Couplings (Ultra High Strength)
Coupling Grade/Type
Hardness tests
UTS
HRC
MPa
Ksi
API Class T
16-23
655
95 Mín
UHS
30-34
980
140 Mín
7/8” with 1” sucker rods – UHS Couplings
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28. Field experience – Field “A”
UHS Couplings (Ultra High Strength)
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Field experience – Field “A”
A major independent producer from Argentina operates a field in Neuquén Basin.
Well Characteristics
Depths: ft ( m)
Fluid rates: bfpd ( m3/d)
This field is operated by rod pumping system (250 wells).
Main problems to solve are related with 7/8” pins and 1” API Class T SH couplings failures
7/8” with 1” sucker rods – UHS Couplings
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29. Field experience – Field “A”
UHS Couplings (Ultra High Strength)
26 November November 2018
Field experience – Field “A”
7/8” with 1” sucker rods – UHS Couplings
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30. Field experience – Well #A
UHS Couplings (Ultra High Strength)
26 November November 2018
Field experience – Well #A
Well
Date
Cause of Intervention
Comments
xxB-95
18-Feb-99
1” coupling failure
16-Mar-99
Pump failure
22-Apr-99
03-Aug-99
¾” rod pin break
04-Nov-99 WO
30-Nov-99
7/8” rod pin break
11-Jul-00
02-Jan-02
UHS Couplings Installation
22-Jun-02
Polished rod break
07-Jan-03
Average service life for 1” SH API Class T couplings
350 days
Service life for 1” UHS SH couplings
1350 days
IPA (index) before the installation of UHS 1” SH couplings: 1.03
IPA (index) after : 0.8
Largest time in service before UHS couplings: 540 days
Running time of UHS 1” Sh Couplings pin : 1350 days – 23 MM cycles
7/8” with 1” sucker rods – UHS Couplings
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31. Field experience – Well #A
UHS Couplings (Ultra High Strength)
26 November November 2018
Field experience – Well #A
Well
Date
Cause of Intervention
Comments
xxB-127
8-Apr-99
¾” rod pin break
12-Apr-99
¾” rod body break
14-Jun-99
7/8” rod pin break
9-Jul-99
Pump failure
3-Jan-00
1” coupling failure
18-Jan-00
11-Mar-00
17-Aug-01
1” rod body failure
8-Feb-02
Polished rod break
29-Mar-02
1” rod pin break
3-Apr-02
15-Aug-02
UHS Couplings Installation
Average service life for 1” SH API Class T couplings
408 days
Service life for 1” UHS SH couplings
1125 days
Largest time in service before UHS couplings: 940 days
Running time of UHS 1” Sh Couplings pin : 1125 days – 14.7 MM cycles
7/8” with 1” sucker rods – UHS Couplings
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32. Field experience – Total of wells
UHS Couplings (Ultra High Strength)
26 November November 2018
Field experience – Total of wells
Well
Date
Service Life
months
Fatigue Cycles
MM cycles
Fluid rate
bfpd (m3/d)
xxB-017
10-Jul-00
63.1
23.7
346.4 (55)
xxB-028
31-Oct-00
59.3
10.8
554.2 (88)
xxB-160
5-Jan-01
57.1
18.0
226.7 (36)
xxB-228
8-Jan-01
57.0
20.9
251.9 (40)
xxB-180
5-Dec-01
46.0
16.9
692.7 (110)
xxB-095
3-Jan-02
45.0
17.9
566.8 (90)
xxB-172
27-Mar-02
42.2
13.7
314.9 (50)
xxB-127
15-Aug-02
37.5
14.7
503.8 (80)
xxB-001
11-Oct-02
35.6
12.9
xxB-178
7-Mar-03
30.7
12.6
629.8 (100)
xxB-111
7-May-03
28.7
6.2
881.7 (140)
xxB-038
22-Sep-03
24.1
9.1
598.3 (95)
xxB-142
6-Feb-04
19.5
3.5
472.3 (75)
xxB-187
18-Jun-04
15.1
2.7
440.8 (70)
7/8” with 1” sucker rods – UHS Couplings
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33. 7/8” with 1” sucker rods – UHS Couplings
UHS Couplings (Ultra High Strength)
26 November November 2018
Conclusions
Rod pumped wells with high loads could experience failures at sucker rod strings that increase the operative costs of the field.
Assuming a good h&c and make-up practices, that failures are (in general) related with the mechanical resistance of the materials involved.
Both experiences presented are the result of a task force that involves the operators and suppliers (manufacturers).
Those products had shown a very good performance. An important reduction in the number of well interventions, as well as downtimes associated result in a cost reduction for those fields.
The simplicity of these solutions make them easily applicable to diverse well conditions.
7/8” with 1” sucker rods – UHS Couplings
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34. 7/8” with 1” sucker rods – UHS Couplings
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Questions
THANKS !!!
7/8” with 1” sucker rods – UHS Couplings
26 November 2018