Absrracr-The transfer impedance between conducting coilsis evaluated to estimate the downhole dielectric properties that can contribute to more effective exploration and production of gas/oil reservoirs. The earth formation with a borehole-mud filtrate invasion is simulated by concentric zones of variable dielectric properties to account for rocks saturated by different fluids. We have imposed analytical restrictions to allow only magnetic-dipole coupling between logging coils and to limit logging source frequencies from 10 to 30 MHz for typical coil spacings. Depending on the depth of invasion front, guided waves mag exist in the invaded formation. When guided waves do not exist, rapidly converging branchcut integrations are used to evaluate the transfer impedance. When the invasion front begins to support guided waves the numerical convergence becomes somewhat slower using spatial-hand-limited integrations. Both types of integration are used to produce inversion charts from which dielectric properties and invasion-front radii can be estimated from downhole-measurable transfer impedances. Ambiguity in parameter inversion is also demonstrated to provide insight for developing a future inverse process based on array processing of adequately sampled data. Box 5800, Albuquerque, N M 87185. P. C. Reardon is with Science Applications. Inc., Albuquerque, NM 87109. dielectric mandrel mud ,invaded Peter C. Lysne received the Ph.D. degree in physics from Arizona State University, Tempe, in 1966.He is with Sandia National Laboratories, Albuquerque, N M , where he has worked in the areas of shock waves physics and the modeling of the constitutive relations of geologic materials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.