Research On The While Drilling Electromagnetic Relay Transmission Circuit System

The transmission system of drilled electromagnetic relay circuit is a technology that uses electromagnetic wave to transmit the azimuth information of the underground strata through the relay transmission device,which plays an important role in increasing the depth of the underground transmission.And this transmission method is widely applied because of its simple structure and long transmission distance.Compared with foreign countries,domestic MWD technology is relatively backward,mostly in the laboratory stage,and there is no mature product.Therefore,if we want to break the monopoly situation of foreign countries,we must develop high quality MWD equipment independently.As the major oilfield companies have been stationed in this field successively,the development of relay while drilling circuit is a currently hot tackling task.Based on the research background of MWD above,this thesis designs and researches the receiving,forwarding and transmitting functions of electromagnetic relay transmission circuit instrument while drilling.The contents of the work included are as follows:(1)According to the technical requirements and engineering requirements of the project,the block diagram and scheme of the transceiver system for electromagnetic relay transmission circuit while drilling are designed.(2)To the receiving and transmitting part of the relay circuit system,a low noise filtering and amplifying scheme is raised to achieve the pre conditioning function of the electromagnetic logging.In the digital signal processing,it is proposed that the FPGA minimum system is responsible for the BPSK demodulation.In the external control program.The STM MCU is responsible for the modulation.So that the whole process of receiving and re transmitting from relay is realized.(3)To the size of drilled drill rod instrument,a scheme based on highly integrated SOC hardware circuit system is proposed.This integration scheme realizes signal sampling,demodulation and modulation of DAC,which greatly saves the area of PCB.In the selection of the coefficient of the drilled relay circuit,an external RF control module is used to control the time interval of the relay while drilling.(4)At the end of the test,the test results show that the relay principle prototype produced by the project can perform signal receiving,transmitting and forwarding functions normally.On this basis,it can also change the relevant parameters of the drilled relay circuit system through the external control circuit module.It also provide a good foundation for further optimization and improvement of the following instruments.