The Development of a Downhole Corrosion Sensor for Condition Monitoring of Electrical Submersible Pumps

Transcription

1 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 PAU, FRANCE 5-7 APRIL 2016

2 Content 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

3 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 Monel shaft corroded (seawater application) seawater application

4 Corrosion Factors and Mitigation Factors affecting downhole corrosion Gas composition and quantity Water ph Pressure (Partial pressure) Temperature Flow velocity and Pattern Fluid / oil type 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

5 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%

6 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 WL-N Existing firmware was modified to accept and transmit data from the Corrosion sensor S R

7 Sensor Design Requirements Three prototypes designed and built in 2015 as technology demonstrators to meet the following key requirements: Measurement Performance Metal Loss Range Sensitivity Environmental Requirements Pressure & Temperature Rating 5 kpsi, 80 C Shock Resistance Maximum Package Size Diameter Length Electrical Interface 0 to 5mm 1 mpy detection in 24 hours 100g < in. < 12 in. Power Consumption <1W Communication Online digital every 4 seconds

8 Corrosion Measurement Principle: Electrical Resistance Patented CEION technology used to achieve high-resolution measurement of extremely small resistances mω

9 Corrosion Sensor Overview Interface to centraliser Electronics Housing Interface to MGU Reference Element Protective Shroud Sample Element Sample Element Reference Element

10 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.

11 Sensor Qualification Testing Shock & Vibration (ISO ) 8 x 100g shocks on all axes Hz vibration sweeps at 5g on all axes 2 hour random endurance test at 6g rms Thermal Testing Thermal endurance: 90 C for 7 days Thermal cycling: 65 to 80 C 24 times at 5 C per minute. Preliminary Reliability Testing PCBs (4off) soaked at 95 C for 3 months

12 Sensor Performance Test Tested in brine under in a sealed environment Tested under low (N 2 ) and high (CO 2 ) corrosion LPR measurement used as a reference Corrosion rates calculated over a 6 hr window Good agreement with reference rate

13 Sensor Performance Test Target Achieved Resolution (nm) Time to observe 1 mpy (hours) Measurement range (mm) 5 5 Cumulative Metal Loss has been postprocessed to determine Metal Loss Rate, using a Least Square Fit approach.

14 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

15 Author Contact Information Name Tom Elson Dan Clarke Stewart Barlow Ashwin Chandran