Data Transmission Technology Of Deep Well Drilling Based On The MSK Wireless Communication

Along with the petroleum, natural gas and other energy and mineral resources industry development, deep oil well testing, drilling and mining work is increasingly important. As the important link of drilling, downhole information and the data acquisition mode has become the focus of the industry. Relative to the cable transmission cost is huge, the defect of complicated operation, wireless transmission cost saving, simple operation, has become a research hotspot. Due to deep well wireless transmission applied to special, high temperature and high pressure, high noise and deep well, how to guarantee the harsh environment of the wireless transmission of this paper and discuss the focus.Firstly, several measurement while drilling method introduction, pointed out all sorts of measurement while drilling data transmission the advantages and disadvantages. Based on the drilling method for data signal transmission problems and difficulties in the analysis, put forward this research used by the MSK wireless data transmission signal detection method of deep well.On the formation of transmission line channel had the preliminary understanding, on the MSK modulation principle are studied in detail, realize MSK modulation is modulation mode is more suitable for the formation of wireless transmission. Constant envelope characteristics better able to deal with nonlinear power transform ground noise channel; in order to respond to the formation of high frequency channel signal power attenuation, this research uses extremely low frequency signal (center frequency20Hz), MSK signal power centralized characteristics are well adapted to the low frequency signal bandwidth of small features; MSK modulation the implementation is generally more complex, here for the sake of simplicity, using AD9854DDS chip technology to achieve DDS MSK modulation; in the wake of the antenna design, give full consideration to the formation of conductive properties of a dipole antenna, the in-depth study, using internal drill pipe jacket tube double dipole antenna to transmit MSK modulation measurement data. In order to further verify the feasibility of the antenna, and the electromagnetic wave transmission method was studied, and through Matlab simulation software for calculation formula of simulation, draw the conclusion can be used for communication of dipole antenna. At the receiving end to receive to the downhole measurement of transmission to the measured data, the MSK prior to demodulation, studies using50Hz notch filter and the6order Bessel filter to receive the signal de-noising processing. After demodulation, as the MSK coherent demodulation error rate is smaller than other forms, coherent demodulation is to achieve.Finally, the whole system is in100meters of the test wells, field test, obtained better result. According to a large number of experimental data and theoretical analysis in theory in the1Km underground can be achieved on the ground measurement data transmission.