A three-dimensional transmission line matrix method (TLM) for simulations of logging tools

A three-dimensional (3-D) transmission line matrix method (TLM) in cylindrical coordinates for the simulation of logging tools is formulated and programmed. The radiation properties of a coil-type antenna in a conductive medium are analyzed and simulated with TLM formulations. The symmetrical condensed nodes (SCN) are adopted. This algorithm can be applied to both induction and measuring-while-drilling (MWD) tools in both the time and frequency domains, and the formation can be anisotropic. Perfectly matched layer (PML) absorbing boundary conditions are used to simulate an infinite boundary in real logging situations. Verifications and some examples are presented.