Shu Yizhan, Hua Chenquan, Zhao Zerun, Wang Pengcheng, Zhang Haocheng, Yu Wenxin, Yu Haobo
College of Control Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China.
Sensors (Basel). 2024 Aug 7;24(16):5123. doi: 10.3390/s24165123.
Due to their high accuracy, excellent stability, minor size, and low cost, silicon piezoresistive pressure sensors are used to monitor downhole pressure under high-temperature, high-pressure conditions. However, due to silicon's temperature sensitivity, high and very varied downhole temperatures cause a significant bias in pressure measurement by the pressure sensor. The temperature coefficients differ from manufacturer to manufacturer and even vary from batch to batch within the same manufacturer. To ensure high accuracy and long-term stability for downhole pressure monitoring at high temperatures, this study proposes a temperature compensation method based on bilinear interpolation for piezoresistive pressure sensors under downhole high-temperature and high-pressure environments. A number of calibrations were performed with high-temperature co-calibration equipment to obtain the individual temperature characteristics of each sensor. Through the calibration, it was found that the output of the tested pressure measurement system is positively linear with pressure at the same temperatures and nearly negatively linear with temperature at the same pressures, which serves as the bias correction for the subsequent bilinear interpolation temperature compensation method. Based on this result, after least squares fitting and interpolating, a bilinear interpolation approach was introduced to compensate for temperature-induced pressure bias, which is easier to implement in a microcontroller (MCU). The test results show that the proposed method significantly improves the overall measurement accuracy of the tested sensor from 21.2% F.S. to 0.1% F.S. In addition, it reduces the MCU computational complexity of the compensation model, meeting the high accuracy demand for downhole pressure monitoring at high temperatures and pressures.
由于具有高精度、出色的稳定性、小尺寸和低成本等优点，硅压阻式压力传感器被用于监测高温、高压条件下的井下压力。然而，由于硅对温度敏感，井下温度高且变化很大，会导致压力传感器的压力测量出现显著偏差。温度系数因制造商而异，甚至同一制造商的不同批次也有所不同。为确保高温下井下压力监测的高精度和长期稳定性，本研究提出了一种基于双线性插值的温度补偿方法，用于井下高温高压环境下的压阻式压力传感器。使用高温联合校准设备进行了多次校准，以获得每个传感器的个体温度特性。通过校准发现，被测压力测量系统的输出在相同温度下与压力呈正线性关系，在相同压力下与温度近似呈负线性关系，这为后续的双线性插值温度补偿方法提供了偏差校正依据。基于此结果，经过最小二乘法拟合和插值后，引入双线性插值方法来补偿温度引起的压力偏差，该方法在微控制器（MCU）中更易于实现。测试结果表明，所提出的方法将被测传感器的整体测量精度从21.2%F.S.显著提高到0.1%F.S.。此外，它降低了补偿模型的MCU计算复杂度，满足了高温高压下井下压力监测的高精度要求。
