The Analysis Of P-wave Reflection Coefficients And Amplitude In Anisotropy

In this dissertation, with the utility of Matlab, we try to analyze the characteristics of P-wave in anisotropy through the analysis of reflection coefficient in three typical models which are VTI, HTI, Orthorhombic, and the comparing of traveltime in samples. In the meantime, with consideration of the importance of NMO, the difference of several approximated equations for the calculation of traveltime has been analyzed based on the stiffness coefficients of rock samples, and furthermore, the uncertainty could be quantified in anisotropy.(1) The codes about the computation of coefficients have been written in Matlab, and been compared with JAVA APPLET developed by the CREWES. The result is the same. The propagation of wave in anisotropy also has been modeled by FD methods. One can see that the wavefield has been severely distorted because of the existence of anisotropy.(2) According to the theory of anisotropy, it has been divided into three models, and independent stiffness matrix has been analyzed. In Matlab, the variation of coefficients and amplitude has been shown. So effect of anisotropy could be delineated. In the previous analysis, the assumption of isotropic case will be doubted in the reality. And the anisotropy is close the real. With the development of 3D exploration, people can easily get the anisotropic information from P waves.(3) In the analysis of traveltime, difference of different approximated equation is so obvious. Compared with the Thomsen Linear Approximation, the second-order Tsvankin equation is much more closed to the Thomsen Asymptotic one, and that is the reason why it has been used often in processing.