Well deliverability is an important issue in forecasting the performance of many gas condensate reservoirs. Condensate accumulation near the wellbore can cause a significant reduction in productivity, even in reservoirs where the fluid is very lean. Generally, the well deliverability is affected by two pressure-drop sources due to depletion and condensate buildup.
Recently Rapid spreadsheet tools have developed to evaluate the well performance using material balance equation for depletion and two-phase pseudo pressure integral for well inflow performance. Most of them account for the effects of negative inertia and positive coupling in the calculation of gas relative permeability.
This paper introduces a new method for calculation of the well productivity in gas condensate reservoirs. This method uses the concept of two-phase pseudo pressure integral without any need to estimate the radius of two-phase region. The average reservoir pressure is calculated by using a general material balance equation. The only data required for implementing this method is PVT data, relative permeability curves and table of well flowing pressure versus time.
The approach is validated by using a single-well fine grid compositional simulation of a hypothetical reservoir model over a typical range of gas condensate reservoir parameters. The results show a reasonable agreement between the fine grid and the proposed approach. The new technique can be encoded on a spreadsheet in order to forecast the gas condensate well performance very rapidly.