Research And Design Of Cross-tester Data Transmission And Data Acquisition Circuit System

Real-time monitoring of the temperature and pressure data of underground formation is of great significance for the development of oil and gas wells.However,due to the problem of mechanical structure of downhole tester,the conventional formation testing methods can not effectively monitor down-hole temperature and pressure information.In order to solve the above problems,the research group proposed a data transmission scheme combining wireless data transmission and cable transmission across the tester to complete the purpose of monitoring downhole temperature and pressure data in real time.Therefore,the research group established the ground simulation experiment platform,carried on the voltage-frequency characteristic experiment,obtained the passband of the data transmission channel,and eventually verified the feasibility of the scheme.On this basis,the research group designed the data acquisition circuit system of downhole temperature and pressure and a cross-tester data transmission circuit system respectively.The data acquisition part mainly takes the PIC18F46K40 single chip microcomputer as the main micro-control unit,uses the DS18B20 temperature sensor and the Keller 8 pressure sensor to carry on the data acquisition.After the conditioning procedures such as amplification and A/D conversion,the data will be stored in the flash memory to realize the basic function.The data transmission part of the cross-tester adopts a 2FSK modem,the transmitter designs 2FSK data modulation circuit based on DDS technology,and the receiver designs 2FSK demodulation circuit based on PLL technology,thus realizing the basic function of cross-tester data transmission.