Modeling Well Performance Under Nonequilibrium Deposition Conditions

摘要

A nonequilibrium well productivity decline model is developedand solved analytically under the same simplifying conditionsof the previous equilibrium models. The solution iscompared with the analytical solutions of the equilibriummodels. It is demonstrated that deposition for nonequilibriumflow conditions is less compared to equilibrium flow conditions.Charts are developed and presented for the productivityindex and skin factor in terms of relevant dimensionless parameters.In addition, the formulae for estimation of the radiusof the plugging region (skin radius), and the producing timerequired for partial plugging of the formation at various percentagesof the initial porosity and the time for complete pluggingof the formation are derived. Numerical examples arepresented, illustrating the applications of the formulations, andthe predictability of the productivity decline of wells. The newimproved model alleviates the limitations of the previousequilibrium models and more accurately predicts the productivitydecline. This model can be used for determination of therate of productivity decline by scale formation, the skin radius,and hence the well inflow performance and for scheduling ofthe treatments necessary for effective well stimulation.