the development of a downhole corrosion sensor for

MCE Deepwater Development 2016

PAU, FRANCE • 5-7 APRIL 2016

The Development of a Downhole

Corrosion Sensor for Condition

Monitoring of Electrical Submersible

Pumps

Dr. Tom Elson, Stewart Barlow, Dan Clarke - Teledyne Oil & Gas

Ashwin Chandran - Baker Hughes


1. Impact of Corrosion 2. Problem Statement 3. ESP System Overview 4. Corrosion Measurement Principle 5. Corrosion Sensor Overview 6. Sensor Design 7. Sensor Testing 8. Conclusions & Next Steps

Content


Corrosion in Electrical Submersible Pumps (ESP)

• Typical corrosion types on ESP equipment • Galvanic

• Pitting

• Microbiologically influenced corrosion

• Sulfide stress corrosion cracking

• Water injection and sea water applications

• Graphite corrosion

• Stress corrosion cracking

• Crevice corrosion Cr 13% corroded –

seawater application Monel shaft

corroded

(seawater

application)


Corrosion Factors and Mitigation

• Exotic corrosion-resistant alloys • Expensive

• Corrosion-resistant coatings • Cannot be used everywhere

• Not very effective at higher temperatures

• Chemical Treatment - Corrosion Inhibitors • Blind injection of a predetermined

quantity

• Cannot measure effectiveness

• Factors affecting downhole corrosion

• Gas composition and quantity

• Water

• pH

• Pressure (Partial pressure)

• Temperature

• Flow velocity and Pattern

• Fluid / oil type


Problem Statement Opportunity:

• ESP failures due to corrosion is a real problem, resulting in costly workovers.

• Chemical treatment needs feedback to be more effective.

Gaps:

• Surface corrosion measurements are a lagging indicator; no downhole monitoring of corrosion.

Approach:

• Develop a downhole corrosion sensor capable of measuring 1 mpy in 24 hr.

• Proven technology of electrical resistance monitoring to detect metal loss.

Impact:

• Immediate action on corrosion rate change

• Optimized injection - reducing chemical cost

• Minimal work-over cost due to corrosion failure

• Total customer annual cost expected to be reduced by 10%


ESP System Overview

• Existing Baker Hughes downhole platform was used for power and communications

• Corrosion sensor interfaces mechanically and electrically with existing WellLift-N gauge

• Interface is pressure sealed with electrical

feed-throughs • Existing firmware was modified to accept

and transmit data from the Corrosion sensor

S R

WL-N


Sensor Design Requirements

• Three prototypes designed and built in 2015 as technology demonstrators to meet the following key requirements:

Environmental Requirements

Pressure & Temperature Rating 5 kpsi, 80 °C

Shock Resistance 100g

Measurement Performance

Metal Loss Range 0 to 5mm

Sensitivity 1 mpy detection in 24 hours

Maximum Package Size

Diameter < 3.375 in.

Length < 12 in.

Electrical Interface

Power Consumption <1W

Communication Online digital every 4 seconds


Corrosion Measurement Principle: Electrical Resistance

Patented CEION© technology used to achieve high-resolution measurement of extremely small resistances ≈mΩ


Corrosion Sensor Overview

Interface to centraliser

Interface to MGU Electronics

Housing

Reference Element Protective Shroud

Sample Element

Sample Element

Reference Element


Sensor Design Analysis

Computational Fluid Dynamics Used to ensure that the flow over the sensor element is uniform and representative.

Finite Element Analysis Used to ensure mechanical integrity of the housing under pressure and other loads.


Sensor Qualification Testing

Shock & Vibration (ISO13682-6) • 8 x 100g shocks on all axes • 25 – 1000 Hz vibration sweeps at 5g on

all axes • 2 hour random endurance test at 6g rms

Preliminary Reliability Testing • PCBs (4off) soaked at 95°C

for 3 months

Thermal Testing • Thermal endurance: 90°C for 7 days • Thermal cycling: 65 to 80°C 24 times

at 5°C per minute.


Sensor Performance Test

• Tested in brine under in a sealed environment • Tested under low (N2) and high (CO2) corrosion • LPR measurement used as a reference • Corrosion rates calculated over a 6 hr window • Good agreement with reference rate


Sensor Performance Test

Cumulative Metal Loss has been post-processed to determine Metal Loss Rate, using a Least Square Fit approach.

Target Achieved

Resolution (nm) 70 30

Time to observe 1 mpy (hours)

24 10

Measurement range (mm) 5

5


Conclusions & Next Steps

• Successful technology demonstrator for Downhole Corrosion Sensor for ESP condition monitoring by Baker Hughes and Teledyne-Cormon.

• Initial prototypes has successfully completed qualification awaiting field trial.

• Initial performance testing is encouraging with clear corrosion trends evident over short periods of time (<6 hours).

• Integration tests with WellLift-N on an ESP with existing surface equipment is complete and prototype sensors are ready for in well field trial


Name Email

Tom Elson [email protected]

Dan Clarke [email protected]

Stewart Barlow [email protected]

Ashwin Chandran [email protected]

Author Contact Information

mailto:[email protected]




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