The Development Of Multi-channel Seismic Exploration Surface-wave Instrument

In the seismic data acquisition and detector are arranged on the surface or near the surface of the earth, to receive the reflected wave, refraction wave and random disturbance, in addition, will receive a by body waves in the medium surface, derived from boundary, mainly spread in the surface wave, known for surface wave. Surface wave is a kind of seismic wave. In view of the surface wave in seismic exploration in the universality and importance, through the development of surface wave instrument collected surface waves to different strata elastic layered analysis.At present, the main use of the surface wave instrument is the transient excited surface wave exploration method, the principle of the use of surface wave dispersion phenomenon. Frequency dispersion is a physical phenomenon in which the wave velocity changes with frequency or wavelength. In oil seismic exploration, using the Rayleigh wave amplitude decay with depth, energy is limited within a wavelength, and by the instantaneous phase of ground vibration wave phase velocity of the Rayleigh wave propagation can be identified, at a distance of a surface at a certain distance from the two detectors placed a receiving surface wave vibration. Through the analysis of spectrum characteristics of make wavelength, wave velocity dispersion curves, underground layer of the Rayleigh wave velocity can be calculated, by Rayleigh wave and shear wave velocity, conversion to obtain the shear wave speed, in order to analyze the surface stratum situation.This design mainly studies the realization of the hardware and software of multi-channel surface wave instrument. The main contents of the study include the design of the overall framework of the circuit, based on Designe Altium design and drawing the schematic diagram and PCB board, and complete the late welding and debugging. Based on the FPGA main control VHDL and HDL Verilog and other hardware description language of the lower computer program design, as well as the MFC based C++ PC software program design.The design of each circuit board can work normally, the software and hardware process is basically completed, the data acquisition is basically correct. Multi channel data acquisition operation is normal.In the design process, AD conversion chip due to the complexity of the external circuit, and the number of chip channels and other reasons for the replacement of the AD chip. Due to the first edition of a large collection of noise, the second version of the amplifier chip replacement, and will be changed to a fixed amplifier multiple amplification, while the number of single board expansion to 16 channels.