Today reservoir engineers are faced with the challenge of evaluating well tests in heterogeneous, complex reservoirs which may include fractures. For such reservoirs analytical methods are not available so numerical simulation is required. We present a finite element simulation system for gas well test analysis in such reservoirs. An automatic finite element grid generation technique provides grid refinement only in regions where it is needed. In this way wells and fractures are rigorously represented. Also wellbore storage and skin effects can be included in the model. Analytical coupling of fracture flow equations with reservoir flow equations, and nonlinear treatment of gas viscosity and compressibility, make the model ideal for gas well testing in fractured reservoirs. Also included in this 2-D model is the the capability of simulating multi-layer, 2-D reservoirs with crossflow only at the wells in a numerically efficient way. The model has been validated against analytical solutions for liquid flow in homogeneous media and has been shown to be correct to high order accuracy.

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