Predicting flow properties using geophysical data: Improving aquifer characterization

The objective of this research has been to improve aquifer characterization. This objective was met by focusing on using rock physics theory and geophysical data to predict flow properties, such as porosity, permeability and clay content. The advantage of using geophysical data to predict these properties stems from the fact that geophysical data are less expensive and more spatially-abundant than lab- or field-measured, flow-property data. This research contributes five newly-developed relationships that significantly improve aquifer characterization. The first development is a general relationship between total and channel (or effective) porosities that is a function of a composite's porous percolation threshold, critical porosity, and a pore space parameter; the percolation threshold and critical porosity define three distinct porosity regions physically, hydraulically, electrically and seismically. The second development is a generalization of Archie's equation that relates electrical resistivity and channel porosity; the relationship is a function of critical porosity and grain sphericity. The third development is a tight empirical upper bound on the resistivity---total porosity relationship; the bound is constrained by the percolation threshold at one end and by the critical porosity at the other. The fourth development is a general relationship between the internal geometry parameter (a) and cementation exponent (m), empirical parameters in Archie's equation; the relationship is defined by a composite's critical porosity, percolation threshold and grain sphericity. The fifth contribution is the development of bounds on the electrical resistivity---seismic velocity relationship through their dependence on porosity. Even though the objectives of this research have been environmentally focused, the resulting developments can also be used to significantly improve petroleum reservoir characterization.