摘要 在 VSP 观测中采用三分量检波器接收,每个分量所记录的信息都是空间波场振动在该分量上作矢量投影的合振动,因此,VSP 资料处理的关键,就是进行波场分离。为了获得好的波场分离效果,必须确定两水平分量的定向和求取偏振角。两水平分量的定向可以借助于直达 P 波的偏振方向在水平面内的投影加以确定。偏振角可通过矢端曲线和瞬时相位法求取。两水平分量定向后,上、下行 SH 波的水平分量被分离到 H_T(t)分量中,上、下行 P 波和转换 SV波的水平分量被分离到 H_S(t)中。将 Z(t)分量和 H_S(t)分量按在垂直平面内估算的下行 P 波偏振角进行坐标转换,即可实现下行波场的初步分离。然后,再联合使用波场分离和反转投影方法对上行波场进行分离。但是,反转投影只能实现上行 P 波和 SV 波的主能量分离,不能完成全波场的分离。文中展示了在PDP-11/24计算机上使用人机交互三分量处理软件的处理效果。
Abstract:Three-component geophone is used to reccrd VSP data.Each ccm-ponent record is the resultant of vector projections which total wave field produces on the component;therefore,the key to VSP data processing lies in wave field separation.In order to receive fine wave field separation effect,we must determine the directions of two horizontal components and the angle of polarization,The directions of two horizontal components can be determined using the projection which the polarization direction of direct P-wave brings in a horizontal plane.The angle of polarization can be calculated using envelope curve of vec-for ends and instantaneous phase method,After the directions of two horizontal components are determined,the horizontal component informa-dons of upsoinJ and downgoing SH waves can be put into HT(t) com-poneat;the horizoatal component informations of upgoing and downgoing waves,and of upgaiug and downgoing converted SV waves are clas-sified into Hs(t) comonent.Downgoing waves can be roughly separated out by performing coordinate transformation of Z(t) and Hs(t) compa-nents ae}or3in} to th0 polarization angle of downgoing P-wave that is estimated in vertical plan.Upgoing wave fields can be separatad out by making both wave field separation and reverie projection.However,the use of reverse projection can only separate out the major energy of upgoing P-wave and SV wave,but fails to separate off all wave fields.Processing results are shown which were obtained using PDP-11/24 computer and interactive softwares for three-component VSP data.