Experimental and Modeling Study of two phase gas/oil relative permeability at near miscible condition

One of the main parameters in modeling of two phase gas and oil flow is an accurate relative permeability functions. This requirement will be more intensified when the miscibility condition approaches. In miscible condition due to reduction of interfacial tension between oil and gas phases, behavior of conventional relative permeability functions will change and this changing affects on oil and gas recovery and also pressure drop of reservoir fluid.In this work, this changing will be investigated based on the behavior of two phase oil and gas relative permeability at near miscible condition in order to observe the trend of relative permeability curves when miscibility condition approaches. So these curves were determined by using some conventional and also numerical implicit methods. The experiments were done on two types of Iranian reservoir's core samples including fracture dolomite and sandstone.In this study conventional method such as (Toth, Civan) method and also numerical method were used in which the conventional methods are used as the initial guess of 1-D, two phase flow simulation code and then by optimizing the results of the code and experiments, we approach to implicit permeability functions. To have fairly accurate criteria of approaching to near miscible condition, the minimum miscibility pressure (MMP) has been calculated based on various methods such as empirical correlations and slim-tube experiment.As the conclusion by approaching in to near miscible and also miscible condition, the curvature of relative permeability curves of both implicit and conventional methods reduce and the intersection point of non-wetting and wetting phase relative permeability curves tends in to lower amount of non-wetting phase saturation. As the main point, non-wetting phase relative permeability increases more rapidly than the wetting-phase.Finally by using the well-known commercial software, we find that this model is fairly accurate and this accurate recognition of relative permeability functions can be used to have a better knowledge of fluid flow in regions with low IFT.

کلیدواژه ها:

Minimum Miscibility pressure (MMP) ، Inter Facial Tension (IFT) ، Experimental unsteady state displacement tests ، (Toth ، Civan) method ، Numerical Modeling ، Optimization