Abstract
This paper shows how to establish correlation between effective permeability as a function of pressure using well test analysis techniques in three-phase gas-condensate systems. Rigorous mathematical treatment led to correlations to estimate pseudopressure for gas condensate fluids that also use surface production data. The main purpose of developing correlation from well test analysis techniques is to use it in well performance analysis in such systems. Thus pressure transient techniques are helping to establish the flow behavior of gas condensate systems in their later life. Reservoir properties can also be estimated, however, to estimate absolute permeability, knowledge of relative permeability is required.
Three-phase gas condensate systems include water producing gas condensate reservoirs. Such wells are often equipped with artificial lift to unload the produced water. To model such a three-phase flow, relative permeability curves are needed. Getting relative permeability curves becomes further demanding when reservoir conditions of pressure and temperature coincide with near critical conditions. Analysis of pressure data in such multi-phase systems requires the exact knowledge of the individual phase surface rate, which itself is a demanding task and requires the separator and stock tank properties of gas and liquid phase. In this paper we have eliminated the knowledge of individual phase surface rate. Instead, we have developed models that use the surface measured rate of these phases.
Finally, an example is solved to show the use of the new technique developed.
