基于CAN总线的智能型井下压力传感器监测系统设计

套管阀是实施主过程欠平衡钻井的关键工具。结合胜利油田井下压力监测系统进行研究,设计并实现了一种基于CAN总线技术以超低功耗单片机MSP430为核心的具有温度补偿的智能型压力传感器监测系统,对井下的实时压力及温度信号进行实时采集,为井下套管阀开启提供保证。采用硬件补偿以及曲线拟合和牛顿插值法进行软件温度补偿,有效解决了由于温度变化对压力测量带来的影响;采用CAN总线及光电隔离等技术,抗干扰能力比较强,传输距离长,可达10km。通过实验证明,本系统实时性好,精度误差达0.75%,足以满足套管阀阀底压力监测系统研制要求。

Design of a pressure sensor measuring system for oil wells based on CAN bus

Casing valve is one of the key tools in process of underbalanced drilling. Combined with the downhole oil-pressure monitoring system from Shengli oil field, an intelligent pressure sensor monitoring system with function of temperature compensation is designed based on CAN bus in this paper, which uses low power consumption MCU MSP430 as the core, to complete real- time acquisition of pressure and temperature signals and provide guarantee for well casing valves. The hardware compensation and software compensation of curve fitting and Newton interpolation methods are adopted to complete temperature compensation and reduce the impact of temperature change on pressure measurements. CAN bus and the photoelectric-isolation technologies are used to provide system with strong anti-interference capacity, long transmission distance of ten kilometers. The experimental results show that this system has a good real-time and accuracy of 0.75%, which can meet project requirements