A new fast technique for calculation of gas condensate well productivity by using pseudopressure method

摘要

This paper presents a new fast technique to obtain gas condensate well productivity without using simulator. The calculation uses a material balance model for reservoir depletion and Fevang and Whit-son's two phase pseudopressure function for well inflow performance. The two phase pseudopressure technique cannot be applied independently for well performance evaluation since it requires the well production gas-oil ratio (GOR) as an input. Mott proposed a new method to generate a well's production GOR by modeling the growth of the condensate banking (Region 1) without using a reservoir simulator. Also, Xiao and AL-Muraikhi described another way to generate well's production GOR. In this work, an iterative method described to obtain the GOR for each reservoir pressure. High gas velocity impacts such as non-Darcy flow and high capillary number effects can be incorporated into the method. The proposed method has been tested by comparison with the results of fine-grid compositional simulation data in the literature and there is a reasonable agreement between the result of fine-grid simulation and the prediction from the proposed method. The new technique together with Mott's and Xiao and AL-Muraikhi's methods is used to obtain the productivity of a gas condensate well in a real field in Iran here referred to as SA4. Also, Genetic Algorithm is used for the optimization of history matching parameters from the toolbox MATIAB software. The results of the calculation show that, different methods of predicting GOR are adequate for quick estimation of gas condensate well productivity without using a simulator, but the new technique overlay is simpler and has a lesser error than the other methods.