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Gas and Oil Well Applications: Projects
CALCE - Schlumberger Project
Physics of Failure based Reliability Assessment of Printed Circuit Boards used in Permanent Downhole Monitoring of Oil Wells
Permanent
Downhole Gauge (PDG) is an integral part of the modern
“Intelligent well?completions used for real-time downhole
monitoring of pressure and temperature in an oil reservoir. The life
cycle of permanent downhole gauges is primarily characterized by high
temperature, vibration and shock environments. Reliable operation of
about 5 years is required from these systems due to high intervention
costs. This thesis work is a systematic effort to study the reliability
of the printed wiring boards used in the permanent downhole monitoring
applications, considering their entire life cycle, for operation at
temperatures close to 150?/span>C, using the physics of failure
methodology. The reliability assessment was performed on a
representative permanent monitoring electronics gauge called the HPQGTM
(Hyper Permanent Quartz Gauge) and was motivated by the need to operate
these gauges at higher temperatures upto 150?/span>C. A methodology
to address life cycle load considerations with electronics used for oil
and gas extraction and production applications was developed. This
methodology was used to define the life cycle of the HPQGTM. Numerical
simulations were used to predict the leading failure mechanisms at the
component level as well as the assembly interconnect level.
Electromigration and metallization corrosion were identified as the
leading failure mechanisms at the component level. Solder joint fatigue
due to vibration and solder failure due to shock overstress were
identified as the leading failure mechanisms at the board interconnect
level. Accelerated thermal testing was performed to assess reliable
operation of the boards for a life cycle of 5 years at operating
temperatures upto 150?/span>C. Conclusions on the reliability of the
boards have been drawn based on the results and suitable
recommendations for improvement have been made.
Report
Presentation
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