Mathematical model for calculating the dispersion coefficient of super critical CO2 from the results of laboratory experiments on enhanced gas recovery

Abstract

A straightforward method is presented for calculating the dispersion coefficient of super-critical carbondioxide (SCO2) displacing methane in a linear porous reservoir. The dispersivity of SCO2 was identified to be a function of injected pressure, in-situ gas composition and injection rate. It was found to vary proportionally to changes in purity of the displaced phase and injection rate, while inversely varying with injected pressure. The aim of this study was to investigate the impact of injection rates and various test conditions (pressure and temperature) on recovery efficiency. Experimental results revealed methane recovery is improved with increasing pore pressure and composition of the in-situ gas, while poor recovery efficiency resulted with decreasing injection rates below 10 cm/h. All experiments were carried out on the same core plug from a single gas field. The dimension of the core was measured as 19.41 cm in length and 12.255 cm in diameter. Preliminary tests indicated air permeability of 92.5 md and porosity of 0.143.