Using Digital Rock Technology to Quality Control and Reduce Uncertainty in Relative Permeability Measurements

摘要

Digital rock technology (DRT) has experienced tremendous progress in the last decade, with an increasing number of companies providing imaging hardware, modeling software and digital core analysis services. While prediction remains the most discussed application of DRT, this paper discusses its use to quality control water-displacing-oil relative permeability (k(r)) experimental measurements. The relative permeability data were collected from three wells over a span of seven years, and they showed a very large spread. To identify potential outliers, we performed micro-CT imaging on six samples that were selected based on similarity in rock properties but differences in measured relative permeability behavior. The three-phase segmentation process was guided by experimental values of porosity, permeability and clay. Consistency checks verified that we could reproduce permeability, drainage capillary pressure, and gas-oil relative permeability. Water-displacing-oil relative permeability was then calculated using pore-network models for water-wet and oil-wet conditions and used to establish a maximum range for each sample. This range was instrumental in identifying suspicious behavior, and reducing uncertainty in recovery predictions by confirming potential outliers and assisting in the upgrading of the experimental relative permeability data.