Study On The Rule Of Ultrasonic Transmission Along Drill Strings

Since 1990's, the technology of down-hole drilling measurement have made significant advancement as a major drilling technology. Although it's no longer difficult to the measurement of real-time signal and signal processing, how to make the underground signal transmission rapidly with long distance and intercommunication between ground and bottom-hole is the key to restrict down-hole telemetry technology. In the paper, by means of theoretical analysis and experiment, study the ultrasonic attenuation along the drill string. Firstly, analyze the ultrasound law of refraction and reflection by the drill string combined with other physical properties of ultrasound wave to get the attenuation model of ultrasonic transmitting along the drill string. Then, describe the parameters'requirements of the ultrasonic transducer for down-hole signal transmission. Design the structure and size of the transducer, matching acoustic and electrical parameters. Introduce the simulation system of down-hole signal transmission while drilling process. Design the various parts'functions of the structure. At last, by the means of experiment verify and regress the results of the theoretical analysis. Prove the feasibility of the ultrasonic transmission by drill string .Design the ultrasound parameters for the Near Bit Measurement System.