Analysis of Signal Attenuation of Continuous Wave in Drill String

In this study, the friction model in non-Newtonian drilling fluid is developed to evaluate the signal attenuation in the information transmission with the continuous wave. A model of transient non-Newtonian power-law pipe flow is developed by assuming a steady viscosity varied only with the radius and the solution is derived analytically in complex domain and time domain. The frequency-dependent friction is developed based on the solution in the time domain and is used in the pressure wave transmission. And the analysis results show that the highest pressure amplification with resonant frequency increases with the power-law index n increase and the resonant frequency increases with the n decrease.