大陆坡地震速度分析与层替代法静校正

由于陆坡带海底地形陡峭、海水低速层突然加厚,影响地震时间剖面的构造形态。因此有必要针对陆坡带的特殊性,开展地震资料解释方法研究工作,以期恢复地下真实构造形态,避免落入速度陷阱而导致解释失误。本文重点介绍在琼东南盆地陆坡带上的研究成果:发现了速度低谷带;提出了用层替代法静校正克服海水剧烈变化造成的影响,并给出了必要的公式及校正量版;论述分层变速时深转换和“精确广角快速深度偏移”处理的剖面同样可以恢复陆坡带下面的真实构造形态。

A SLOPE ZONE SEISMIC VELOCITY ANALYSIS AND LAYER REPLACEMENT METHOD OF STATIC CORRECTION

In slope zones, the subsea topography is generally steep and low velocity water depth thickens suddenly, which affect the shape of structures on seismic sections. Therefore it is necessary to do some method study for seismic interpretation for the characteristics of slope zones, in order to restore the true structure-shape and avoid misleading the interpretation by a "velocity trap". This paper mainly introduces the results of the study done for the slope zone in SE Qiong basin:a low velocity zone is defined, a layer replacement static correction method is proposed to overcome the effects of rapid change of water depth, and also necessary formular and correction chart are given.further-more, it also discusses the layer and velocity variant time-depth convertion. It states thatseismic sections processed by acurate wide-angle, fast depth migration which also can restore the true structure shape in a slope zone.