一种适用于随钻测量的磁传感器的温漂补偿设计

A Temperature Drift Compensation Design for Magnetic Sensors in Measurement While Drilling (MWD)

摘要: 为了降低石油钻井工程中随钻测量(MWD)里磁阻传感器温度漂移对测量精度的影响，本文专门针对各向异性磁阻效应(AMR)传感器与Σ-Δ ADC (模数转换器)的接口设计做了研究。硬件方面采用热敏电阻或者高精度温度传感器来监测环境温度；软件上，则对零值温度磁场偏移的准一阶近似线性模型做了拓展。电路模拟前端还通过控制双AMR磁传感器的励磁电流和参考电压，抑制了直流误差，让系统在−5℃到175℃的环境下，能稳定实现双轴磁场采集，以适应井下设备所处的高温环境。经过标定后，磁阻传感器的测量误差被控制在满量程±0.68%以内，这也为MWD系统的方位测量提供了精度保障。

Abstract: To reduce the impact of temperature drift of magnetoresistive sensors on measurement accuracy in Measurement While Drilling (MWD) during oil drilling engineering, this study focuses on the interface design between Anisotropic Magnetoresistive (AMR) sensors and Σ-Δ Analog-to-Digital Converters (ADCs). In terms of hardware, thermistors or high-precision temperature sensors are used to monitor the ambient temperature. For software, the quasi-first-order approximate linear model for zero-value temperature magnetic field offset is extended. The circuit analog front-end suppresses DC errors by controlling the excitation current and reference voltage of the dual AMR magnetic sensors, enabling the system to stably achieve dual-axis magnetic field acquisition in an environment ranging from −5˚C to 175˚C, thus adapting to the high-temperature conditions of downhole equipment. After calibration, the measurement error of the magnetoresistive sensor is controlled within ±0.68% of the full scale, which provides accuracy assurance for the azimuth measurement of the MWD system.