Coupled CO₂ sequestration and enhanced condensate recovery in gas condensate reservoir using experimental design and response surface methodology

Abstract

Valuable condensate in gas condensate reservoirs which will drop out and is left in the reservoir at reservoir pressure lower than dew point pressure can be recovered via CO2 injection by the mechanism of condensate re-vaporization as a result of pressurization. At the same time, part of the injected CO₂ can be sequestered in the reservoir, allowing the methodology to be attractive.The objective of this study is to investigate the application of CO₂ sequestration and enhanced condensate recovery in gas condensate reservoir for different flood design parameters and strategies using compositional reservoir simulation model. It is to better quantify the potential of reservoir condition over a wide variety of parameters and strategies with the need to find optimum operational strategies with the aid of Experimental Design and Response Surface Methodology. The parameters and strategies studied include permeability, injection scheme (water alternating gas vs. continuous CO₂ injection), injection and production well type (vertical vs. horizontal), vertical to horizontal permeability ratio, injection rate, well spacing, and injection time. The amount of CO₂ stored and condensate recovery factor are considered as two responses.The results show that 1000-md permeability gas condensate reservoir with high kv/kh has potential to implement. Optimum strategies are provided by Experimental Design with less time and cost compared to full runs of simulation.