1. n. [Formation Evaluation]

The use of repeated forward modeling of a logging tool response to produce modeled logs that very closely match the measured logs. The final model is then the log analyst's best estimate of the formation properties. Iterative forward modeling is a hand-operated inversion. The technique is used mainly for laterologs and induction logs when the formation or the environment are complex, so that the environmental effects cannot be separated and treated individually by automatic inversion. Iterative forward modeling allows the log analyst to use local knowledge and petrophysics to select between the many possible solutions that are mathematically correct. These cases occur most often in horizontal wells, or vertical wells with the combined effects of invasion and large resistivity contrast between beds.

See related terms: forward modeling