New Modification on Production Data of Gas Condensate Reservoirs for Rate Transient Analysis

Techniques of production data analysis for single-phase oil and gas reservoirs have advanced significantly over the past few years. These techniques range from traditional (i.e., Arps, 1945; Fetkovich, 1980) to modern methods that account for the variation of operating conditions at the wellbore. However, the application of these latermethods to gas condensate reservoirs is a challenge. The authors aimed to extend the applicability of modern production data analysis (single-phase flow) to analyze the production data of a gas condensate reservoir (two-phase flow). A single-phase production model consists of (a) a material balance equation, (b) the solution of diffusivity equation for gas flow subjected to constant rate and constant pressure boundary conditions, and (c) the presentation of a material-balance-time function. Using a compositional reservoir simulator, long-term production data have been generated over a wide range of the gas condensate reservoir parameters. The simulation result is compared with the prediction from the single-phase gas reservoir model, which uses a modern production analysis method. The error level is evaluated and a correlation for treatment of the single-phase analysis method is developed. Finally the results show that the methodology developed can be successfully applied for analysis of production data of a gas condensate reservoir.