Rock-physics modeling is a term normally referring to the modeling of sonic signals, particularly travel times. In more common sense it is applicable  to the modeling of any logging tool response in a given geological environment.

It is normally done explicitly for the QI seismic interpretation purposes, such as AVO and Inversion, in some cases for the seismic-well ties. The purpose of the exercise in this case is to bring sonic and density logging response to the virgin, undisturbed by the well presence, formation conditions. In some cases to the reservoir conditions, which were not encountered by a well penetration ( brine to gas fluid substitution for example). The procedure provides basic inputs for the AVO and Inversion workflow. In addition to that allows to do a pre-processing test of the AVO or Inversion techniques sensitivity to the desirable parameters, such as reservoir presence, fluid presence or a reservoir quality, in a particular geological environment. This allows to make an early design either to  proceed or not with the study.

Doing rock-physics modeling for mostly two decades, we have discovered several additional applications to these techniques:

  • Permeability estimation through the rock-physics techniques. It can be done in the well or in 3D using inversion results.
  • 3D porosity from Inversion results, using calibrated rock-physics model.
  • Applications into geomechanics. Including dynamic elastic moduli in the in-situ formation conditions, Biot’s coefficient estimations, dynamic to static elastic moduli conversion using RP approach ( IToil-SV technology), static elastic moduli changes with stress in pure elastic region, pore pressure estimation.
  • Rock-physics modeling provides an excellent validation to the existent petrophysical model.