Studies on vector wave field separation method for 3D3C VSP data
Sun Wen-bo1,2, Sun Zan-dong1,2
1. Lab for Integration of Geology and Geophysics, Faculty of Natural Resource and Information Technology, China University of Petroleum, Changping District, Beijing City, 102249, China;
2. State key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Changping District, Beijing City, 102249, China
Abstract：In this paper the authors introduced the vector wave field separation method which can realize the wave field separation for multi-component non-zero offset VSP data,it is a regional parameter inversion method in which the single channel record is the stack of down-going and up-going P-wave and down-going and up-going share wave,and each wave consists of Fourier component (wave form),apparent slowness and polarization angle. By utilizing the nearby traces the forward model of the inversion problem was established. When separating wave field for multi-component VSP data,polarization vector was generally brought in the forward model so that the uniqueness and stability of the resolution of the inversion problem got raised,but non-linear problem was brought in. In this paper by utilizing the optimization algorithm which constraint conditions were applied,the optimal polarization angle and velocity values were calculated and the non-linear problem was overcame,the linear equations were solved so the Fourier component information for each wave were obtained,at last wave separation was realized by inverse Fourier transform in time domain,at the same time the velocity for the every type of wave (down-going and up-going P-wave and down-going and up-going share wave),polarization angle and other parameters were calculated,the stability and practicability of this method was proven by wave field separation processing for the multi-component non-zero VSP model data and field data.
