时变校正方法研究与应用

THE RESEARCH AND APPLICATION TO TIME-VARIANT CORRECTIONS METHOD

地表一致性静校正方法的基本假设是:地震波在低降速带为垂直入射、垂直反射,即地表同一位置,静校正量只与低降速带的厚度、速度和充填速度有关,而与地震波的传播路径无关.这一假设是为了计算表层的延迟时而对表层模型的近似.随着地震勘探的不断精细,以往的构造勘探逐步转向岩性勘探,叠加剖面地震响应的地质特征是正确岩性反演结果的基础.因此叠加过程中如何减小对振幅、频率、波形的影响,处理中如何保护好岩性信息是实现勘探转型的关键.本文通过模型道的约束,利用相关方法,消除了地表非一致性引起的剩余时差,使反射相位同相性增强,减少了叠加过程对地震高频成份的损失及对地震波形的改变,有利于地震属性的反演和AVO油气检测的自动识别.

The basic hypothesis of the surface-consistent static corrections is that the round raypaths geometry of seismic wave through the weathering layer is vertical. That means the static corrections in the same location are just related to the thickness, the velocity of the weathering layer and the instead velocity, but they are independent of the travel paths of seismic waves. In fact, this is an approximation to the real near-surface model in order to effectively calculate the values of weathering static corrections. With the higher precision demanding of the seismic exploration, the target to explore the geological structure is turning to research the characters of lithology.Becanse the seismic impulse characteristics in stack section are elements to get good result of lithology inversion, it becomes more important for exploration transfer how to reduce the change of the amplitude, the frequency and the shape of waves during stacking, and how to protect the lithology natures in data processing. This paper presented a correlation method for correcting traveltime differences resulting from non-surface-consistency by constrained modeling, which can enhance the consistency of reflecting signal phase and reduce losing of the high frequencies and changing of the shape of seismic wave, meanwhile, it is propitious to seismic inversion and AVO estimates.