UNCERTAIN RESISTIVITY SOUNDING AND EQUIVALENT MODELS

Problems of the resistivity sounding method may be reparametrized by means of Dar Zarrouk—or generalized D.Z.—transformations. A complete set of equivalent models is subdivided into three classes: initial models, intermediate models, and all other models. Equivalent reparametrized models are subdivided into three analogous classes. There is no one-to-one mapping of intermediate primary and intermediate reparametrized models. Non-trivial equivalent models are generated from initial models via intermediate reparametrized models. A method is developed to find equivalent models relative to the uncertainty of resistivity soundings. There are different forms of approximate equivalence laws, apart from those commonly accepted. The equivalence depends considerably on the “flatness” of the sounding curve. For mean flatness, the electric models exhibit the (hp±2)-equivalence rather than the (hp±1)-equivalence.