A Study to Estimate the Onset Time of an Impulsive Borehole Source

임펄시브형 시추공용 탄성파 송신신호 시작시간 측정에 관한 연구

  • 이두성 (한성대학교 정보공학부)
  • Published : 2003.05.01

Abstract

Accurate estimation of the first arrival travel time is an essential task to obtain a high resolution velocity tomogram. Accuracy of the travel time estimation may be influenced by two factors; geological and mechanical. A serious mechanical factor is the source firing control problems. We found the control problems in the records generated by tome impulsive borehole sources. The problems are; irregular firing control and uncertainty in estimation of the absolute firing-times shown in records. Definitely, the time difference will introduce an error to the first arrival times, and accordingly; it will cause some distortion in the resulting velocity tomogram. A method to determine the firing time is suggested here. The method determines the optimum onset time by comparing the horizontal and the NMO velocity with various amount of delay time adjustment.