METHOD AND APPARATUS OF ELECTRICAL RESISTIVITY MEASUREMENTS IN GEOLOGICAL FORMATIONS EMPLOYING MODELING DATA

摘要

A method, and a system, using computer software to measure characteristics of a geologic formation (22) using vertical side scan resistivity measurements (Rm) to model characteristics such as hydrocarbon reservoirs. The method employs modeling data (23) to remove unwanted information from a signal carrying infromation from a signal carrying information concerning the geologic information (11) and models the resistivity of geologic formations. The spatial distribution and orientation to the magnetic fields are the same, differing only by a constant related to the casing attenuation factor (24). The magnetic field outside of the cased borehole is reduced in amplitude by an attenuation factor associated with the liner. The magnetic field produced at a point outside of the liner is a function of the product of term for the attenuation factor of the liner, ke and a term for the response of the geologic formation, f. Both terms are independent of the other. by factoring (28) and removing information concerning the 20th attenuation factor, ke, accurate measurements of the geologic formation may be determined.