A Fast Method for Productivity Index Calculation of Vertical Wells in a Gas condensate reservoir

estimating well productivity index in gas - condensate reservoirs is one of the challenging problems in production engineering . The prediction of fluid behavior near the well is very difficult in these reservoirs. This complexity makes the well type selection a risky decision. we aim to present a simple and rapid method to compare well productivity index in order to reduce the risk of the decision. in this paper we present a new method for calculating the productivity index of vertical wells. this proposed method is based on material balance calculation and recalculating the two -phase pseudo-pressure integral at each time interval for each pressure step and using numerical methods to find the gas well rate value by means of a spreadsheet.the pseudo-pressure integral includes high velocity effects and allows for the change in produced fluid composition caused by the formation of the condensate bank. although this method is very simple and easy to use, it provides a tool for rapid estimation of well productivity index in a specific reservoir during the production perioid. it can be applied in reservoir management and decision making procedures during reservoir study. fine grid simulators usually need a lot of input data. moreover the effects of a change in any of the parameters take a lot of time to be modeled in these simulators. our developed method helps engineering to compare the effect of changes in the input data on the well productivity of different well types more quickly.