Pore-Scale Numerical Analysis of Spontaneous Imbibition ina Fractured Porous Medium: Influences of Wettability, IFTand Heterogeneity

Spontaneous imbibition is known to be of the most effective mechanisms for oil recovery in fractured reservoirs. The aim of the present investigation is to address pore-scale mechanism of two phase flow in artificial fractured porous media and to assess the effects of wettability and heterogeneity on water-oil displacement process. Fractured reservoirs with water-wet matrix which are flooded by water orexperience water encroachment from an active aquifer, are not immersed instantaneously in water, but the water level gradually advances through fractures surrounding matrix. For such a modeling, the description of a physical interface separating different phases inside a pore volume is a problem of crucial importance. The two phase flow in fractured porous media was simulated using the coupled Navier– Stokes and Cahn–Hilliard phase field equation and solved by COMSOL Multiphysics™ with finite element method. The fractured reservoir model used in this study is a two-dimensional model which consists of two homogeneous matrix block and a horizontal fracture in the middle of matrixes. Obtainedresults showed the highest recovery magnitude and recovery rate is related to strongly water wet grains (the least contact angle). Weakly water wet systems with contact angles equal to 45o and 60o showed lower recovery factor, i.e. 56% and 38% respectively. In addition, an increment of 0.01 N/m in IFT value could improve ultimate recovery by 11%. Also, increasing fracture width result in a higher displacementrate in early time and a lower rate in late times. The present study demonstrates that phase field method (PFM) can be a reliable approach to capture pore scale mechanisms in fractured porous media at porescale

کلیدواژه ها:

Pore-Scale Modeling ، Spontaneous Imbibition ، Wettability ، Fractured Reservoirs ، Computational Fluid Dynamic ، Phase Field Method