Methodology of Fluid Composition Calculation on the Basis of "Black Oil" Simulation

Abstract

The paper presents a methodology of hydrocarbon fuid composition calculation on the basis of gas and condensate profiles calculated in a black oil simulator. The methodology is based on the straight dependency of the condensate-gas factor (CGR) and the reservoir pressure (Pres). In order to determine a fluid composition a dependence function between a fraction of a hydrocarbon component and CGR is created using a PVT-simulator. Having a relationship between CGR and a hydrocarbon fraction a fluid composition can be calculated using the average CGR from black oil simulation results. This methodology gives a fraction of every individual component in comparison to composition modelling, where real components should be groupped in pseudocomponents. Proposed methodology assumes several constraints -the methodology should be applied just for gas condensate reservoirs without oil rims and the reservoir should be developed on depletion. In the work black oil and composition simulation results were compared. The paper can be useful for reservoir engineers working with gas condensates because it allows reducing simulation time without losing information about fluid composition.