| VideoLog Network HD Downhole TV is a kind of logging equipment used to obtain downhole video data,and its measurement results are intuitive,accurate,and reliable,which has a wide application prospect.As an important part of the downhole TV,the high-temperature telepathic short section is responsible for the data transmission between the downhole instrument and the surface system,and its temperature resistance and transmission rate determine the overall performance of the downhole TV.The article designs and implements a high-temperature telepathic short section for downhole TV.The two main difficulties are to ensure real-time and accurate data transmission,and to ensure the reliability of electronic circuits under high temperature.For real-time and accurate data transmission.In this article,the system structure,key technologies and mathematical representation of DMT are studied;the transmission characteristics of seven-core cable,the principle of cyclic redundancy and the principle of downhole power supply are explained;the parameter indexes and design scheme of high-temperature telecommutation short section are formulated according to the actual logging requirements,and DSP and FPGA are used as the system processing According to the actual requirements of the well logging,the parameters and design plan of the high-temperature telemetry short section were developed.The reliability of electronic circuits under high temperature is addressed.The article analyzes the impact of high temperature on the circuit and proposes the design idea of high temperature circuit,and adopts the SIP(system level packaging)scheme to solve the reliability problem of the electronic circuit of the high temperature remote transmission short section.The thermal simulation of the electronic circuit model of the high-temperature teleport short section was carried out by COMSOL software,and it was verified that the SIP scheme has low thermal resistance characteristics,and some process problems in the design process of the SIP scheme were proposed.After the design was completed,the functions of each part of the high-temperature telepathic short section,the temperature and pressure resistance indexes and the transmission performance of different cable lengths were tested and applied to the field logging operation,and the results showed that it could work continuously at 135℃ for 4h and the transmission rate reached 2.3Mbps on the 5000 m logging cable,and the temperature resistance and transmission rate have met the actual logging requirements,which has high It has high application value. |
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