Numerical SimulationandImprovement of Whitson Method for Compositional Gradient Calculationsin Petroleum Reservoirs

Thisstudyworksonenhance theaccuracy ofWhitsonalgorithm, applied for calculating compositionalchanges in petroleum reservoirs. These improvementsare implementedby choosingthe proper calculated value ofthe parameter λ andusing the more proper way to choose the pressureestimation in algorithm. In thismethod both liquid and gas phase calculations use just one reference point in calculations. Reference point is a point where certain compositions and pressure are set for a certain depth. Resultsof this improved numerical algorithmare matched well withthe results of commercialsoftwarethat validate this method. Results showthat calculations would be more accurate by inserting some modifications into algorithm