Premium MMS-NR (AISI 4138M) Sucker Rods

Beam Pumping WorkshopHouston, Texas

October 4 - 7, 2005

Premium MMS-NR (AISI 4138M)Sucker Rods

Alejandro F. Ameglio – Head Technical Services

Tenaris Rods Division

April 19, 2023 Premium MMS-NR (AISI 4138M) Sucker Rods 2

• Chemical Analysis

• Mechanical Properties

• Laboratories Tests

• Field experiences

• Conclusions

Contents


Chemical AnalysisElement Grade UHS-NR

(4330M)Grade MMS-NR

(4138M)Grade Plus

(1530M)

C (Carbon) 0.30-0.35 0.38-0.43 0.31-0.36

Mn (Manganese) 0.70-0.95 1.10-1.40 1.4-1.6

S (Sulfur) 0.025 Mx. 0.025 Mx. 0.025 Mx.

P (Phosphorus) 0.025 Mx. 0.025 Mx. 0.025 Mx.

Si (Silicon) 0.15-0.35 0.20-0.40 0.25-0.40

Ni (Nickel) 1.65-2.00 0.30 Mx. 0.15 Mx

Cr (Cromium) 0.80-1.10 0.60-0.90 0.2 Mx

Mo (Molibdenum)

0.20-0.30 0.25-0.35 0.05 Mx

V (Vanadium) 0.035-0.07 0.04-0.07 0.10-0.15

Nb 0.025-0.045

Cu (Copper) 0.25 Mx. 0.25 Mx. 0.25 Mx.As it can be observed, main difference between Grades UHS-NR and MMS-NR is the Nickel (Ni) content.


Mechanical Properties

Grade UHS-NR (4330M)

Grade MMS-NR (4138M)

Grade Plus (1530M)

YTS (ksi) 115 Min. 115 Min. 115 Min.

UTS (ksi) 140-160 140-160 140-160

Thermal process Normalized Normalized Normalized

Partially tempered

Mechanical properties are the same for all Grades


A set of lab tests were done to evaluate the performance of the different steels at corrosive environments

•CO2 (“sweet” corrosion)•SSC (Sulfide Stress Cracking) Resistance•Localized attack in H2S environments

Two steels were tested: AISI 4330M and AISI 4138M

Lab Tests


At CO2 environments both steels showed approximately the same performance.

Besides that, AISI 4138M showed a lower corrosion potential compared with the AISI 4330M.

Analyzing the behavior of them at H2S environments, both showed a poor performance.

None of them are recommended for sour service.

Lab Tests

Results of Lab tests


A major company operates a field at Neuquen Basin (Río Negro Norte Field)

Going trough a natural declination process, wells were changing the ALIFT systems from ESP to Rod Pumping.

Main characteristics of the field are:

• Depths: 8200-9800 ft (2500-3000 m)• Production rates: 300-600 bfpd (50-90 m3/d)• Water cuts: 10-40%• Vertical wells

Load levels make Grade D rods not applicable at the first stage of field development

Field experience

Field history


Field experienceField evolution until Oct 2001

0

5

10

15

20

25

30

Date

Qty

Accumulated failures Rod pumped wells

Field evolution


Field experienceField evolution until Oct 2001

Pump failures, 3, 27%

Rod failures, 7, 64%

Others, 1, 9%

Major problems were related with sucker rod failures

Field evolution


As the failures rates were constantly increasing, it was decided to do a complete analysis of the field data

A task force that included production engineers and specialized technicians studied data including:

•Fluid analysis•Annulus gas determinations (H2S and CO2)•Bacterial measurements (SRB-Sulfate Reducers Bacteria)•Failure analysis (all of the rod failures were analyzed)•Operating conditions (spm, loads, etc)•Handling & care practices, make-up procedures, etc.

Field experience

Field data analysis


Annulus gas determinations showed a low content of CO2 (partial pressure < 3psi). From this point of view, there is no a corrosion problem

However, CO2 in fluid analysis were detected (concentrations between 40-70 mg/lt)

No H2S were detected, neither SRB (Bacteria).

Failure analysis indicated a corrosion-fatigue process as the responsible for the rod breaks.

NACE MR0175 (carbon steels or low alloy steels should not contain more than 1% of Ni)

As a final conclusion, a change in the steels of HS sucker rods were decided (from AISI 4330 to AISI 4138)

Those wells whit loads level less than 130% (SF=0.8) (Grade D) will be installed with Grade D rods

A task force that included production engineers and specialized technicians studied data including:

• Fluid analysis• Annulus gas determinations (H2S and CO2)• Bacterial measurements (SRB-Sulfate Reducers Bacteria)• Failure analysis (all of the rod failures were analyzed)• Operating conditions (spm, loads, etc)• Handling & care practices, make-up procedures, etc.

Field experience

Field data analysis - Conclusions


Field experienceField evolution (2000-2004)

Total failures vs. total of rod pumped wells

0

18

3031

33

5

29

34

37 37

0

5

10

15

20

25

30

35

40

Year

Qty

Accumulated failures Rod pumped wells

MMS-NRInstallation

Field evolution after AISI 4138 rods


Field Experience

Rod body failures

13

9

4

2

0

2

4

6

8

10

12

14

2001 2002 2003 2004

Year

Failu

res

QTY

Grade MMS-NR (4138)Installation date

Rod body failures evolution


Field experience

Premium MMS-NR (AISI 4138) Evolution

5

7

12

15

1

4

1

0

0

2

4

6

8

10

12

14

16

2001 2002 2003 2004Year

Fai

lure

s Q

TY

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Ro

d p

arts

Wells Rod Parts

Premium MMS-NR (AISI 4138) failures evolution


Field ExperienceSucker Rod Type

0

2

4

6

8

10

12

14

16

18

20

2001 2002 2003 2004Year

Qty

. o

f W

ell

s

Grade UHS-NR Grade MMS-NR Grade D Others

Grade of sucker rods installed


ConclusionsThis material has shown to have a better performance at

corrosive environment than the other type of high strength sucker rods previously tested.

A reduction in the pulling interventions rate (increase in service life) has been observed.

Even with a “sweet” corrosive environment (CO2), and because of its reduced content of Nickel (Ni), the material is less susceptible to corrosion-fatigue processes that were affecting the other type of sucker rods.

As with all of the high strength rods in a corrosive environments, an effective corrosion inhibition program must be applied.

Besides that, with loads level less than 140% (SF=0.8) Grade D rods are also an alternative that should be considered

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