复杂地区近地表对速度分析的影响

THE IMPACT OF NEAR-SURFACE IN COMPLEX AREA ON THE VELOCITY ANALYSIS

对于复杂地区的地震勘探来说，速度分析是一个难题。因为叠加速度分析是建立在“时距曲线为双曲线”这一假设条件之下的，在复杂地区这一假设往往会遭到破坏，从而影响到速度分析的精度。因此，为了揭示速度分析误差产生的原因和规律，帮助人们充分认识叠加速度分析结果，进而采取行之有效的方法加以校正，从近地表这一因素出发，通过理论计算，详细而系统地论述了充填速度和基准面、地表和高速层顶形态、静校正、速度横向变化等因素对速度分析的影响。通过分析认为，复杂地区近地表会对速度分析产生较大误差，且原因是比较复杂的。

For the seismic exploration in complex area, velocity analysis is always a problem. Stacking velocity analysis, based on the assumption that time-distance curve is hyperbolic, is often disobeyed in complex area, so the accuracy of velocity analysis is influenced. In order to reveal the causes and laws of velocity analysis error and to fully understand the result of stacking velocity analysis and adopt effective correction methods, this paper particular- ly and systematically discusses the factors that influence the velocity analysis through theoretical calculation, inclu- ding filling rate and base level, configuration of surface and high-speed layer roof, static calibration and lateral velocity variation, etc. The analysis indicates that big error of velocity analysis is caused by near surface in the corn-plex area with various influential factors.