Design Of Sending Subsystem Of Well Parameter Telemetry Experimental System

The main jobs of the acoustic telemetry system for oil wells is the signals transmitting and processing during the course the parameters of the temperature and the pressure under the bottom of the oil wells being taken to the mouth of the well by the acoustic wave. We try to set a transducer at the bottom of the well, which will drive the drill pipe to vibrate lengthwise, thus, with the acoustic wave as information carrier and with the drill pipe string as transmitting channel, the parameter at the bottom of the oil well could be transmit to the ground in real time.The main content in this paper are design of sending subsystem under well in well telemetry system. It consists:1. Two experiments were made in laboratory and at the scene of well. According which the project and the transducer were designed.2. Modulation and coding are discussed. The system adopts FSK signal as modulation and DFT as demodulation. And the capability of noise rejection of DFT is discussed. The system adopts positive—negative coding. The LFM single is adopted as synchronization. And the capability of LFM single through bandwidth is also discussed.3. The DSP system and the DSP chip are introduced. A comparison is made between the singlechip and the DSP. The system adopts TMS320LF240x DSP made by TI company. It is introduced in the paper and the DSP program controlling transmitter to send special signal was compiled.4. The system adopts both real time processing and collecting data for subsequence procession. Collection system is introduced and Lab VIEW program was compiled.