INDUCTION LOGGING

摘要

A method of providing a computed induction log of an induction logging tool (15) run through an interval of a wellbore (1) that extends through a layered formation (3) invaded by wellbore fluid comprising: (1) computing a first response of the induction logging tool (15) by solving for each formation layer (5, ..., 11) the Maxwell equations for the electromagnetic field using a one-dimensional concentric cylinder model not taking into account the effects of formation layering and of the orientation of the logging tool (15) with respect to the formation layering, and determining for each formation layer an equivalent resistivity that gives for a homogeneous environment a response of the induction logging tool (15) that equals the first response; and (2) solving for a number of logging points the Maxwell equations using a one-dimensional layered model using the equivalent resistivities as computed in step (1) wherein the effects of the formation layering and of the orientation of the logging tool (15) with respect to the formation layering are taken into account, to provide the computed induction log of the induction logging tool (15).