基于无线射频识别的井下工具控制技术
The Control Technology of Downhole Tools Based on Radio Frequency Identification
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摘要: 针对投球式井下工具控制技术在使用过程中的不足,研究了一种指令接收与控制执行一体短节.根据电子标签在井筒低电阻率液体环境中工作时的姿态,通过试验对比各类频段的电子标签传输性能,并进行读写器天线匹配设计,以提高电子标签读写成功率.应用流体力学分析导致电子标签损坏和影响读取效率的因素,设计出了能够适应各类钻井液环境的天线匹配电路,研制了读写器电路系统和相关嵌入式程序.试验结果表明,125和134 kHz低频RFID标签的读写效果最佳,能够满足井下指令接收与控制执行一体短节的需求.研制的指令接收与控制执行一体短节,在泵送速度3 m/s条件下读取成功率为100%.研究结果表明,通过优选电子标签的工作频率和优化读写器天线的功率匹配设计完成的电子标签指令系统,可以应用于井下工具控制.Abstract: In order to overcome the shortcomes of ball injection downhole tools,the working process and the tool structure of a RFID triggering downhole tool were discussed.Fluid mechanics were used to analyze the influence factors of RFID damage and reading efficiency.An antenna matching circuit which could adapt itself to all kinds of drilling fluid environment was designed,and a reader circuit system and related embedded program were developed.The experimental results proved that the reading effect of 125 kHz and 134 kHz low frequency RFID were best and they satisfied the requirements of the downhole Radio Frequency Receiver.In conjunction with the theoretical analysis and the experimental results,the Downhole Radio Frequency Receiver was designed.The coupling efficiency was improved by using long distance antenna matching circuit.The experimental results showed that the reading success rate was 100 % under 3 m/s velocity of mud flow.The research results showed that RFID label instructions designed system could be applied to the control of downhole tools through the optimization of electronic label work frequency and optimal read power antenna matching.