New Perspectives on Vogel Type IPR Models for Gas Condensate and Solution-Gas Drive Systems

Abstract

Abstract In this work we propose two new Vogel-type Inflow Performance Relations (or IPR) correlations for gas condensate reservoir systems. Onecorrelation predicts gas production the other predicts condensateproduction. These correlations link reservoir rock and fluid properties(dewpoint, temperature, and endpoint relative permeabilities) to theflowrate-pressure performance for the system. The proposed IPR relationships for compositional reservoir systemsare based on data from over 3000 compositional reservoir simulation runs withvarious fluid properties and relative permeability curves. The resultingIPR curves for gas condensate systems are quadratic in nature like theVogel IPR trends (the Vogel profile generally presumed for the case of asolution gas-drive reservoir system). However in the gas condensate casethe coefficients in the quadratic relationship vary significantly depending onthe richness of the condensate and the relative permeability. A model topredict these coefficients was developed using an alternating conditionalexpectation approach (optimal non-parametric regression). This work also includes a discussion of the Vogel IPR forsolution-gas drive systems. The original work proposed by Vogel is based on anempirical correlation of numerical simulations for a solution-gas-drivesystem. Our work provides a critical validation and extension of theVogel work by establishing a rigorous, yet simple formulation forflowrate-pressure performance in terms of effective permeabilities andpressure-dependent fluid properties. The direct application of this work is to predict the IPR for a givensystem directly from rock-fluid properties and fluid properties. Thisformulation provides a new mechanism that can be used to couple flowrate andpressure behavior for solution-gas-drive systems and it may be possible toextend the concept to gas condensate reservoir systems.