Drainage capillary pressure and resistivity index from short-wait porous plate experiments. 9th Middle East Geosciences Conference, GEO 2010.

Abstract

Reliable experimental capillary pressure (Pc) and electrical properties (RI) as functions of saturation (Sw) history are essential as inputs for static and dynamic modeling of a reservoir. The only technique that simultaneously gives both Pc and Sw-RI relationship as functions of saturation history, and does not rely on a model with underlying assumptions for calculation, is the standard equilibrium method. This method is also known as the porous plate technique. The only disadvantage with this method is that it is time consuming caused by the low flux through the diaphragm (porous plate). In this study we present drainage capillary pressure curves and resistivity index measured on reservoir rock samples by the standard equilibrium method at reservoir conditions. In parallel with this, a sister plug set has been analyzed by interrupting intermediate capillary displacement pressures before reaching equilibrium, with the objective of establishing Sw-RI relationship much faster. The results show that it is possible to establish identical Sw-RI relationship with a time-saving factor of three for the rock type under study. Both data sets are analyzed with an extrapolation routine as an attempt to also predict capillary equilibrium for the fast plug set, that is, capillary drainage curve. Numerical interpretation of the experiments has been done as an attempt to investigate factors and optimized design of the interrupted capillary displacement pressure sequence for various porosity and permeability classes.