The similarity theory applied to the analysis of multiphase flow in gas-condensate reservoirs

An important part of the world's hydrocarbon reserves is constituted of gas-condensate deposits, and as such, they have been the subject of intensive research over the years. Gas-condensate reservoirs are complex systems, and their performance analysis involves the handling of highly nonlinear partial differential equations and sophisticated thermodynamic models. For the case of noncondensing natural gas reservoirs, analytical solutions based on the exponential integral function are readily available for the analysis of infinite-acting behavior in production and injection wells. No such tool is available for the analysis of infinite-acting behavior in gas-condensate reservoirs, and the associated analysis of well deliverability is a topic of continuous research. This paper investigates the implementation of the similarity variable theory in the context of the analysis of depletion behavior in natural gas reservoirs. The main objective of this work is to present a novel application of the similarity theory for the case of the analysis of complex systems such as gas-condensate reservoirs, without introducing any simplifications to the inherent nonlinearities present in the associated governing equations.