Determination of model reliability in 3-D resistivity and I.P. inversion

Abstract

Mineral deposits frequently have complex structures that can only be resolved by 3-D inversion of resistivity and I.P. data. A nonlinear optimisation routine is commonly used to create a 3-D model from the measured apparent resistivity and I.P. data. It is particularly important to be able to assess the reliability of the anomalies seen in the inversion model before further tests are conducted. In this paper, we examine the model resolution (MR) and volume of investigation (VOI) approaches in determining model reliability. The MR method produces sections that are easier to interpret but more computationally intensive that puts practical limitations for models with more than 50000 cells. The VOI method can be used for any data set where an inversion can be carried out, but produces sections with more complex patterns and prone to local artefacts. Either method should be used for any interpretation to discern anomalies that are likely to be supported by the data.