Improved Method to determine the characteristics of Terrestrial formations in the vicinity of drilling Wells and apparatus for implementing the method

摘要

A well logging system is provided which simultaneously employs a conventional deep induction log and a radio frequency dielectric log to differentiate similar high resistivity fresh water and oil prospective zones. A 16 megahertz radio frequency dielectric induction logging system which is responsive to both conductivity and permittivity of the earth derives a signal primarily related to both of these properties. A conventional 20 kilohertz deep induction system is used to derive a signal which is primarily a function of conductivity alone. When combined in accordance with predetermined relationships according to the invention the two measurements can be used to find oil prospective zones.