由于其准确性高,出色的稳定性,小尺寸,成本低,硅压阻式压力传感器用于监测高温下的井下压力,高压条件。然而,由于硅的温度敏感性,高且变化很大的井下温度导致压力传感器的压力测量中的显著偏差。温度系数因制造商而异,甚至在同一制造商内的批次而异。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井下高温高压环境下压阻式压力传感器的温度补偿方法。使用高温共校准设备进行了多次校准,以获得每个传感器的单独温度特性。通过校准,结果发现,在相同温度下,被测压力测量系统的输出与压力呈正线性关系,在相同压力下,与温度呈近似负线性关系。作为后续双线性插值温度补偿方法的偏差校正。基于这个结果,经过最小二乘拟合和插值,引入双线性插值方法来补偿温度引起的压力偏差,这更容易在微控制器(MCU)中实现。测试结果表明,该方法显著提高了被测传感器的整体测量精度,从21.2%F.S.提高到0.1%F.S.降低了单片机补偿模型的计算复杂度,满足高温高压下井下压力监测的高精度需求。
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.