TWO-PHASE FLOW PROPERTIES PREDICTION FROM SMALL-SCALE DATA USING PORE-NETWORK MODELING

摘要

Mercury invasion performed on real porous media provides small-scale data characterizing pore-throat size distributions needed to calculate multi-phase relative permeabilities.For an accurate prediction of multi-phase transport properties other small-scale information on the rock structure and wettability may also be required.The objective of this work is to evaluate the prediction accuracy based on the interpretation of mercury invasion capillary pressure curves only.A pore-scale modeling approach is used to model the multi-phase flow and calculate gas/oil relative permeability curves.The characteristics of the 3-D pore-network are defined with the requirement that the network model satisfactorily reproduces the Pc curve,the porosity and the permeability.A sensitivity study on the effect of the input parameters on the prediction of capillary pressure and gas/oil relative permeability curves is presented.The simulations show that different input parameters can lead to similarly good reproductions of the experimental Pc,although the predicted Kr are somewhat widespread.This means that the information derived from a mercury invasion Pc curve is not sufficient to characterize transport properties of a porous medium.Other information is required to constrain the description of a rock sample and ensure a correct interpretation of the Pc curve.Comparison of predicted and experimental relative permeability curves gives insight into the critical parameters that need to be known in order to get more realistic predictions.