Modeling and analysis of phase shift of continuous wave transmission in drilling fluids
The waveform distortion caused by phase shift during continuous wave transmission in drilling fluid is one of the key issues hindering the field application of the drilling fluid continuous wave data transmission technology.In this study,as-suming that the pressure of drilling fluid on the same drill string cross-section is equal and the flow velocity has a radial distri-bution,a drilling fluid continuous wave phase shift model was proposed based on the two-dimensional axisymmetric transient flow theory and using the small signal analysis method.The model was verified with the results of ground experiments.The effects of frequency,transmission distance,drilling fluid density and viscosity,and drill string inner diameter on the phase shift were analyzed using the model.The results show that the phase shift increases approximately linearly with the increase of frequency,drilling fluid density and transmission distance,and it decreases gradually with the increase of drill string inner diameter.The viscosity of drilling fluid has almost no effect on the phase shift.The drilling fluid channel can be regarded as a linear phase channel.
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维普
