Field scale and economical analysis of carbon dioxide, nitrogen, and lean gas injection scenarios in Pazanan gas condensate reservoir

Abstract

Liquid dropouts around the wellbore in gas condensate reservoirs causes severe reductions in gas production rates, the permanent loss of a large portion of volatile and valuable condensates, and a wrong estimation of well deliverability. It is believed that applying diffusion coefficients and the Generalised Pseudo Pressure (GPP) method leads to more accurate modelling of reservoir performance. Hence, using a compositional simulator, a sector of Pazanan reservoir (in the southwest of Iran) with the average permeability of 42 md (original case) and 0.1 md (tight case) is modelled. The results demonstrate that diffusion coefficients could be ignored in two systems, and the GPP method leads to acceptable results in permeable case while, in tight system, it underestimates the well deliverability. Finally, using the GPP method, various gas injection scenarios in the reservoir (original case) at pressures below the dew point (maximum condensate appearance) are technically and economically investigated which show that gas cycling scenario is the optimum solution.