The role of supercritical CO2 in gas well health issue – liquid loading

Liquid load or condensate banking is a common well health issue in gas/gas-condensate reservoirs that decreases well productivity by a factor of two to four. Due to the depletion of bottom-hole pressure, the produced liquid accumulates around the wellbore and creates a static column of liquid that reduces gas production until well production ceases. Enhancing gas recovery by CO2 injection is a promising technology because it reduces greenhouse gas emissions and improves CO2 storage. More investigation needs to be conducted to understand the role of supercritical CO2 (SCCO2) in minimising liquid loading. The aim of this research is to examine the impact of SCCO2 in surface tension, condensate viscosity and well productivity. This study consists of simulation and laboratory experiments. Eclipse 300 was used to develop a model that examines the effect of SCCO2 injection on reducing liquid loading issues by varying the well parameters. We found that injecting SCCO2 improved the microscopic displacement efficiency and minimised liquid loading by decreasing the condensate viscosity and the surface tension. The model shows that (1) condensate recovery increases when the injection rate increases up to a limit after which there is no change of production and (2) condensate recovery improves with decreasing production rate.