- ISSN: 2202-0586
- E-ISSN:
-
oa A revised mathematical formulation for induced polarization
- Australian Society of Exploration Geophysicists
- Source: ASEG Extended Abstracts, Volume 2009, Issue ASEG2009 - 20th Geophysical Conference, Dec 2009, p. 1 - 7
-
- 01 Dec 2009
Abstract
Researchers involved in induced polarization studies are well familiar with Seigel’s (1959) definition of the chargeability parameter m as the ratio of the secondary potential drop immediately after an infinitely long injected current is turned off, to the primary potential drop that builds up at the end of the current pulse. A major advantage of Seigel’s formulation is that it allows to recover the intrinsic chargeability of the subsurface applying a simple perturbation to the sensitivity matrix of the background resistivity (i.e. not affected by IP effects) model. In fact he proved that the apparent chargeability above an heterogeneous earth is simply
where mi and ρi represent the intrinsic chargeability and background resistivity of the ρa media (for a layered earth, layers) that compose the subsurface, and pa the apparent background resistivity. This important result implies that the chargeability model can be readily obtained after the resistivity model has been recovered, and forms the basis of well established time domain IP inversion techniques (Li and Oldenburg, 2000a; Loke, 1999; Oldenburg and Li, 1994; Sogade et al., 2006). This manuscript aims at showing a fundamental discrepancy between Seigel’s fundamental theory and many different well accepted IP models. While contradicting in practice Seigel’s model, these other models do make use of important mathematical formulation that Seigel derived from his model.
