Estimating Three-Dimensional Permeability Distribution for Modeling Multirate Coreflooding Experiments

Characterizing subsurface reservoirs such as aquifers or oil and gas fields is an important aspect of various environmental engineering technologies. Coreflooding experiments, conducted routinely for characterization, are at the forefront of reservoir modeling. In this work, we present a method to estimate the three-dimensional permeability distribution and characteristic (intrinsic) relative permeability of a core sample in order to construct an accurate model of the coreflooding experiment. The new method improves previous ones by allowing to model experiments with mm-scale accuracy at various injection rates, accounting for variations in capillary-viscous effects associated with changing flow rates. We apply the method to drainage coreflooding experiments of nitrogen and water in two heterogeneous limestone core samples and estimate the subcore scale permeability and relative permeability. We show that the models are able to estimate the saturation distribution and core pressure drop with what is believed to be sufficient accuracy.