Design Of Downhole Wireless Ball System

In the drilling process,data transmission methods play an important role for the borehole quality.At now time,the available data transmission methods while drilling include cable transmission,mud pulser,electromagnetic transmission,etc.The disadvantages of these technology include high cost,low transmission data rate and narrow application range,etc.Inspired by medical capsule endoscopy,this thesis is aimed to design a high-speed widely-used and low-cost downhole wireless ball system.The ball follows drilling mud into the borehole and communicates with downhole CPU while passing by it and then goes out of the borehole carrying the downhole information to ground.Two solutions for this purpose has been put forward and validated which emphasize on transmission distance and size respectively.Suggestions for further improvement are proposed at the end of this thesis.Main work includes:Aiming at the requirement of small size for the wireless ball and long transmission distance,two possible schemes are proposed respectively.One is based on far-field communication at 433 MHz.The other is based on near-field communication at 13.56 MHz.The implementation of the two communication schemes has been carried out.The related work can be divided into two parts: the hardware and the software design.The former includes chips selection,matching filter network and anti-interference etc.The latter includes one transmitting & multi-receiving broadcasting in downhole and one receiving & multi-transmitting anti-collision function on the ground.Both of two schemes have been tested and communication quality and distance have been verified.Suggestions for future improvement are proposed.