EZEGO CHUKWUEMEKA CHRIS

Condensate banking is a critical flow assurance challenge in gas condensate reservoirs that can reduce well productivity by up to 60% due to near-wellbore liquid accumulation when reservoir pressure falls below the dew point. Accurate prediction of this phenomenon is essential for optimizing field development strategies, well design, and production forecasting. However, conventional cubic equations of state, particularly the widely used Peng-Robinson (PR) equation, systematically underpredict the severity of condensate banking due to fundamental limitations in their mean-field thermodynamic assumptions. This research presents a novel modification to the Peng-Robinson equation of state that incorporates density-dependent attractive forces to better capture the molecular correlations and beyond-mean-field effects that dominate liquid phase behavior in gas condensate systems. The proposed PR-DD (Peng-Robinson with DensityDependent attraction) modification introduces a densitycorrection function, f(ρᵣ) = 1 + c₁ρᵣ² + c₂ρᵣ⁴, to the attractive parameter, where ρᵣ is the reduced density and c₁, c₂ are empirically determined coefficients. This modification addresses the critical deficiency of standard cubic equations in representing the enhanced intermolecular attractions that occur at liquid densities, particularly relevant for accurately predicting retrograde condensation and liquid dropout volumes. The methodology encompasses three major components: (1) development and validation of the PR-DD equation of state against experimental PVT data, including constant volume depletion (CVD) tests showing liquid dropout curves; (2) implementation of PR-DD within a fully compositional reservoir simulator using local grid refinement to capture near-wellbore gradients; and (3) comprehensive comparison with standard PR predictions through parallel simulations of a representative offshore gas condensate reservoir