Non-uniform Numerical Modeling Of The Helical Coils In Anisotropic Media And Logging Applications

Electromagnetic (EM) well-logging tools are one of the many classes of well-logging tools used for applications in oil exploration. EM logging tools have been subject of interest for many decades due to their capability to measure the conductivity (or resistivity) of an earth formation. Earth formation in engineering log become more complicated, in order to explore hidden oil and gas reservoir, drill and well logging technology develop very rapidly in recent years and some new challenges also arise.,Measuring the formation's resistivity and analyzing response of well-logging of all these specific formation structure ,such as the electric anisotropic earth formation,the sand/clays lamina,inclined wells and horizontal wells ,is a challenging problem of Theory and Engineering application facing the logging Engineer. Numerical emulation and simulation EM well-logging tools on the basis of modeling complex earth formation narrowly and researching EM theory of inhomogeneous anisotropic medium can set up well theory and engineering application bases for logging explanations.This paper is based on the current pressing need of EM well-logging and developing targeted topic selection researching work. Major researching content contain forward modeling method of electromagnetic induction well logging mainly grounded on numerical mode matching (NMM). First, we derive two dimension horizontal and vertical NMM in inhomogeneous media, and applied to model and analyze induction log in isotropic cylindrical-vertical layers. By compare two kinds of method's advantages and disadvantages, we extend vertical NMM method to analyze three-dimension tiled-coil antenna (TCA) in anisotropic cylindrical-vertical layers.On the basis of above work, we test and verify result of tilted and horizontal coil antenna (HCA) in isotropic formation, and responses of coil in different tilted angle in anisotropic formation are in the agreement with the paper's result. To research how micro-sand/clays lamina equal to macro-anisotropic formation, we build the experimental models and investigate the equivalence of anisotropic and sand/clays lamina by using experiment and simulation, which have very realistic project value. Finally, we simulate and compare the result of horizontal-coil and tilted-coil well-logging, major investigate these two kinds of tools'different direction resistivity identification ability in anisotropic earth formation. TCA tools can read response of anisotropic formations'amplitude radio (AR) and phase difference (PD) correctly and conquer the weakness which HCA tool only can read the horizontal direction resistivity.