Proper modeling and simualtion of naturally fractured reservoirs is one ofthe most important and challenging issues in reservoir engineering. A dualporosity or dual permeability approach is applied in simulation when fracturesform a flow network. On the other hand, single continuum model, where thefracture system is represented by effective permeability, is commonly used iffractures are discrete or disconnected. Focusing on the letter case, this paperpresents a numerical model that incorporates full tensor permeability in eachgrid block to accurately simulate behaviors of discretely fractured media.

We formulate a flux continuous model using the mixed finite volume elementmethod where the pressure equations, expressed as two coupled first-orderpartial differential equations for pressure and velocity, are solvedsimultaneously. This minimizes the numerical errors occurring in standardmethods caused by differentiation of pressure and then multiplication by roughcoefficients. The saturation equation is to be solved by an implicit pressureexplicit saturation approach.

Numerical examples of simulating flow in fractured reservoirs are presentedto demonstrate the performance of the proposed simulator. The reservoir modelsfor simulation are two-dimensional and include regularly or stochasticallydistributed discrete fractures. Effective permeabilities calculated by thecomplex variable boundary element method are assigned to grid blocks. The samemethod is used to obtain reference solutions of the tracer propagationperformance in the five-spot pattern. The examples validate importance ofaccurate representation of the full tensor permeability for simulation ofnaturally fractured reservoirs.

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