An improved procedure for sub-core property characterization using data from multiple coreflooding experiments

Sub-core properties of reservoir rocks are known to have a substantial impact on core-scale flow and saturation distribution, particularly considering CO2-brine coreflooding. Estimating these properties is important for various applications, e.g., investigation of capillary trapping and numerical modeling of coreflooding experi- ments. In this work we present an improved method for the procedure of Krause et al. (2013) to estimate sub-core characteristic relative permeability and three-dimensional permeability distribution and apply the method to a CO2-water drainage coreflood experiment. The main novelty of the new method is its efficiency, incorporating a simplified procedure for characteristic curve estimation requiring only single-phase flow solutions. The second novelty is the use of saturation data from multiple coreflooding experiments with varying fractional flow of injection. The proposed procedure, using single-phase solutions instead of two-phase flow simulations, is also expected to reduce numerical errors. The results of applying the method to an experiment are presented and shown to validate the simplified method for characteristic curve estimation. Simulations using the estimated properties as input are shown to produce output that approximately match experimental results, considering a number of fractional flows. The new method is found to be about 50-100 times faster to compute in comparison to previous methods with more dramatic speedup for highly heterogeneous rocks.

Automated summary

The study introduces an improved method for estimating sub-core properties of reservoir rocks, which is shown to be more efficient and less prone to numerical errors. Validation of the method is demonstrated in a CO2-water drainage coreflood experiment, with significantly faster computation speed compared to traditional methods.