Analysis of CO2 and brine relative permeability of in-situ core samples with employing double separator

Abstract

The relative permeability of CO2 and brine has a significant impact on CO2 saturation, migration, and injectivity for CO2 geological storage. This study presents a new experimental apparatus consisting of a double separator that can reduce uncertainties in measuring fluid saturation. It was applied to measure relative permeabilities of in-situ cores samples of Berea, Gorae, and Paaratte sandstone. The wettability criteria and Brook-Corey model were applied to explain the characteristics in relative permeability of CO2 and brine. The result for Berea sandstone using the developed apparatus was consistent with results obtained in literatures, and they indicate high residual brine saturation and low end-point relative permeability of CO2. The results for Gorae sandstone show that the residual brine saturation is higher and the shape of the relative permeability curves are more concave compared to those of Paaratte sandstone; these results relate to the water-wetting tendency and dominant capillary flow, respectively. It means that injection of CO2 into Gorae sandstone is expected to be less efficient than into Paaratte sandstone. Therefore, it is reasonable to estimate that less amount of CO2 should be injected into Gorae sandstone compared to Paaratte sandstone.