用VSP数据中下行P-SV转换横波求取横波速度  

Estimation of velocities of shear-waves using downward converted P-SV waves in VSP data

作　　者：徐仲达[1] 郝晓红 徐翔之 施荣富 

机构地区：[1]同济大学,上海200092 [2]东海公司,上海200030

出　　处：《石油物探》2002年第3期274-278,共5页Geophysical Prospecting For Petroleum

摘　　要：探讨了用零偏移距三分量VSP数据中的下行P-SV转换横波,求取厚度相当于VSP采集点距的地层横波速度。从井下检波器方位校正得到横向垂直分量,对其二维谱中各类波的能量和特点进行分析,通过二维滤波得到信噪比较高的下行转换横波,选取振幅较强的同相轴提取波至时间,获取了横波速度及泊松比。结果表明,即使是零偏移距VSP数据,只要其上有明显可见的转换横波,也能以采集点距的量级计算横波层速度。This paper discusses how to estimate velocities of shear waves traveled in strata using downward converted P-SV waves in VSP data. The thickness of the strata approximately equals to the distance between two adjacent receivers. After adjustment of azimuths for borehole receivers, the TV components of shear waves were determined. The energy and characteristics of different kinds of waves in the 2-D spectra of the resulting components were inferred. Downward converted P-SV waves of high S/N ratio are determined through 2-D filtering. By picking up the travel times for events of strong amplitudes, we computed velocities of shear waves and poissons' ratio. The results indicate that even if the VSP data is zero offset, it is still possible to estimate velocities of shear waves in strata with thickness approximately equaling to the distance between two adjacent receivers as long as the converted P-SV waves is observable.

关 键 词：VSP数据 地震勘探 P-SV转换横波 零偏移距 垂直地震剖面 方位校正 下行转换横波 横波层速度 泊松比 

分 类 号：P631.44[天文地球—地质矿产勘探]