Well logging data interpretation systems and methods

Abstract

A system has been invented for producing a final earth model of part of an earth formation having N (one or more) layers, the method including, in one aspect, generating an initial earth model based on raw data produced by a wellbore logging tool at a location in a borehole through the earth, performing 2-D forward modeling on the initial earth model to produce an interim earth model that includes a set of synthetic tool responses data for the wellbore logging tool, comparing the synthetic tool response data to the raw data to determine whether there is misfit between them; if misfit between the synthetic tool response data and the raw data is acceptable, saving and storing the interim earth model as the final earth model; if misfit between the synthetic tool response data and the raw data is unacceptable, performing 1-D forward modeling N times on the interim earth model, producing a secondary earth model; performing 1-D inversion on the secondary earth model; and either saving the secondary earth model as the final earth model or re-subjecting the secondary earth model to 2-D forward modeling and subsequent misfit comparison. In one aspect the data is overcorrected following the N times 1-D forward modeling step. In one aspect the N times 1-D forward modeling step is accomplished by using a look-up table of stored values for synthetic tool responses. In one aspect the N time 1-D inversion step is accomplished by using such a look-up table.