Algorithm of interborehole travel time tomography using fast ray tracing and its application.
Yin Feng, Wei Yu and Li Youming. Physics Department, Southeast University, Nanjing City, Jiangsu Province, Internal Postcode: 210018
An algorithm of iterative ray travel time tomography is presented, in which velocity is calculated by using the linear interpolation of node point values in triangular grid. In forward operation, ray paths and travel times have their analytic expressions, which greatly cuts computation time. In inversion, the slowness at points on ray path can be calculated by using three order polynomial primary function. After linearized approximation, the partial derivative of travel time with respect to an unknown model parameter is the linear coefficient between the travel time and the model parameter, so that Jacobi matrix can be calculated quickly. Tomographic results of experimental model and real interborehole seismic data prove this algorithm fast, stable and applicable..