利用面波信息调查表层结构的方法

Investigation of Surface Layer Texture Using Surface Wave Information

面波在天然地震和工程地震中分别被用于探测地球的宏观结构和微观结构,面波是石油地震勘探中的干扰波之一,其实,它也同样携带了地球的表层结构信息。石油勘探关注的低降速带属于速度从上到下递增的正向地层结构。通过面波的正演模型计算可知,在石油地震面波分布的频带范围内,主要是面波的基阶模式。运用p—ω变换,能有效提取出石油地震记录中的面波频散曲线。把表层结构划分成等厚薄层,采用光滑度约束,就能通过基阶的面波频散曲线反演出低降速带的横波速度,从而建立表层的结构模型。

Surface wave is separately used to explore the macro and micro structures of the earth in earthquake and engineering seismology, Surface wave, one of disturbing waves in petroleum exploration, carries also the information of surface layers in the earth. The low-velocity layer that concerned by petroleum prospecting belongs to the forward layer structure increasing from the top down. The forward model computation shows that the surface wave mainly exists in the range of base model. With p-o0 transform, the dispersion curves of petroleum seismic records can be effectively picked up. By dividing the surface layer structure into isopach thin layer and adopting smooth restriction, the basic dispersion curves can be inversed into the shear velocity of low-velocity layer, thus developing the structural model of surface layer.