Temperature Compensation Method Based on Bilinear Interpolation for Downhole High-Temperature Pressure Sensors

Area of Science:

• Sensor Technology
• Materials Science
• Geophysics

Background:

• Silicon piezoresistive pressure sensors offer high accuracy, stability, and low cost for downhole monitoring.
• Silicon's inherent temperature sensitivity causes significant measurement bias in high-temperature, high-pressure downhole environments.
• Manufacturer and batch-to-batch variations in temperature coefficients complicate accurate pressure readings.

Purpose of the Study:

• To develop and validate a temperature compensation method for silicon piezoresistive pressure sensors operating under extreme downhole conditions.
• To improve the accuracy and long-term stability of downhole pressure measurements in high-temperature environments.
• To provide a computationally efficient compensation model suitable for microcontroller implementation.

Main Methods:

• Individual sensor temperature characteristics were determined through high-temperature co-calibration.
• A bilinear interpolation approach was developed, utilizing observed linear relationships between pressure, temperature, and sensor output.
• Least squares fitting and interpolation were employed to implement the compensation algorithm.

Main Results:

• Sensor output demonstrated positive linearity with pressure at constant temperatures and negative linearity with temperature at constant pressures.
• The proposed bilinear interpolation method significantly reduced measurement bias.
• The accuracy of the tested pressure sensors improved from 21.2% F.S. to 0.1% F.S.

Conclusions:

• Bilinear interpolation effectively compensates for temperature-induced pressure bias in silicon piezoresistive sensors.
• The method enhances measurement accuracy and reduces computational complexity for downhole applications.
• The technique meets the stringent accuracy requirements for high-temperature, high-pressure downhole pressure monitoring.