Inversion of induction logs based on maximum flatness, maximum oil, and minimum oil algorithms

Abstract

Inversion of induction logs does not yield unique solutions of formation resistivity profiles because of noise. In this work, three algorithms are used to invert induction logs. The first algorithm employs the maximum flatness criterion that is aimed at obtaining a formation resistivity profile that is as close to a constant as possible. The second is the maximum oil algorithm that has the objective of yielding the highest resistivity profile in the reservoir. The third is the minimum oil algorithm aimed at finding the lowest resistivity profile. All three algorithms are subject to the condition that the resulting computed log must agree with the field log within a preset value. These algorithms are stable because noise and depth shift in the field log have little effect on the result.