Numerical Simulation Of The Seismic Wave Propagation For SWD

Seismic while drilling (SWD) is a combination of exploration geophysics and petroleum engineering. It takes the working drill-bit vibration as seismic source, acquiring the reflected wave propagating through the formation. It is useful to evaluate the formation ahead of the drill-bit, predict abnormal pressure and formation interface, and reduce the drilling risk.Because of the low energy of drill-bit vibration and the high energy of rig noise, as well as the superposition of different time and different phasic wave that induce the SWD signal to noise ratio(S/N) much low, make the wave-field much complex, so data processing is very difficult, and that locale experiment present many unknown factors, such as long period, high expenses, unknown geological structure underground, that is disadvantage for developing SWD research .But numerical simulation have the advantage of develop research in control, that is high-efficiency and low-expense numerical experiment technique. This article is based on seismic wave-field simulation software SEISMOD and signal processing software MATLAB, for SWD low signal to noise ratio and continue random seismic-source signal, taking seismic wave equations in sticky and elastic media and the staggered grid high-level finite-difference numerical solution and the signal processing method of the cross-correlation as the central part, makes a SWD numerical simulation experiment solution, the example validate the solution correct. Utilizing this solution to do some numerical experiments, such as SWD wave-field propagation, the time-distance curve character of direct wave and reflect wave, data processing method, deepen the apprehension to SWD wave-field propagation rule and processing method, for SWD technique research offers a efficient research method.