In-flow Equation and Its Application for Low-Permeability and Pressure-Sensitive Oil Reservoirs

It is very difficult to develop low-permeability reservoirs with water injection due to the threshold pressure and pressure sensitivity.When the flowing pressure is lower than the saturation pressure,the inflow performance curve concave to the pressure axial causing a maximum flow rate point.Based on the previous studies and radial fluid pseudosteady state porous flow,a IPR equation with maximum flow rate point for low permeability and pressure sensitivity reservoirs was developed,considering the impacts of threshold pressure gradient and pressure sensitivity effects on reservoir porous flow.The reservoir productivity can be evaluated to determine the maximum flowing pressure and reasonable flowing conditions.The application in Longnan and Xinzhan oilfields indicate that the predicted value agrees with the measured which satisfies the requirement of filed application.It shows that the proposed IPR equation can effectively evaluate the well productivity and determine the allowed minimum flowing pressure and provided the theoretical basis for reasonably developing the low-permeability and pressure-sensitive reservoirs.