Experimental Investigation of Interfacial Interactions of Condensate/Brine/SC-CO_2 Systems at High Pressure and High Temperature Conditions

摘要

The subject of enhanced natural gas and condensate recovery by supercritical CO_2 (SCCO_2) injection tends to be bypassed by researchers despite the existence of several laboratory and field studies of CO_2 displacements in conventional oil reservoirs. While the phase behavior of SCCO_2/condensate system is a critical factor in determining the effectiveness of the recovery process nevertheless, the interfacial tension (IFT) is an important parameter in verifying the efficiency of the displacement process. This paper investigates the IFT behaviour for a CO_2/condensate/brine system at temperatures of 95, 120, 140 and 160 °C, and a pressure range of 1000 to 6000 psi. A high pressure high temperature rig incorporating a pendent drop facility was utilised to simulate reservoir conditions and was subsequently employed to measure the interfacial tensions. The results of this study show that while pressure acts to reform the surface molecules of the CO_2 drop and thus significantly lowers the IFT; temperature however, tends to increase this tension resulting in a declining miscibility of the CO_2-condensate system. This work is part of an integrated project that is conducted for a West Australasian field.