Study of downward communication receiver in rotary steerable drilling tool based on turbine generator

For the existence issues of underground information receiving at drilling, such as the installation space in the drill collar, installation location, and connections to the measurement circuit, etc., turbine generator as detection devices was proposed to achieve downward information received. The instruction encoding was built, and the effective downhole control instruction was generated by the use of drilling fluid pump displacement to format three descending and three ascending pulse transmission modes. The internal structure and working principle of turbine generator were outlined. The receiving of downhole signal was achieved by detecting changes of the turbine generator output voltage. Pulse counting method was used for pulse width measurement. In order to improve the accuracy and to resistant interference in the identification of downhole information, some measures were taken on software and hardware. A linear relationship between the drilling fluid displacement and the turbine generator output voltage was determined through the hydraulic experimental study. The laboratory experiment prove that the three descending and three ascending pulse transmission method is reliable and the receiving device is feasible.