Study on the Downhole Influence Factors of Radio Frequency Identification Technology

Compared with the conventional control method of measuring differential pressure or pitching,the radio frequency identification technology is flexible,and drilling fluid displacement and borehole diameter can be maintained constant during the operation process.However,due to the complexity of downhole conditions,electromagnetic interference affects the stability of a radio frequency identification system in practical application.In order to solve this problem,the electromagnetic influence of radio frequency identification in the underground environment was carried out.Through analysis,it was determined that downhole metal and different types of drilling fluid were the main factors of influence or interference.According to the working environment and structure characteristics of radio frequency control system,the finite element simulation model of electromagnetic environment was established t,the influence degree and variation rule of downhole metal environment and different types of drilling fluid were analyzed and verified by means of lab test.The simulation results showed that the eddy current effect of downhole metal decreased as the space of the antenna and the casing of downhole tools increased,and the influence of drilling fluid would increase with its electro-conductibility increasing.Therefore,the space between the antenna and the inner wall of downhole tool casing should be increased properly during the design of downhole tools.The influence of drilling fluids could be solved by control circuit optimization.