Abstract:

In the oilfield where pressure is maintained by water injection, when the bottom hole pressure is below the saturation pressure, the inflow performance curve is deflected toward pressure axis and the maximum production point occurs on the curve. As such, the old inflow performance relationship (IPR) is no longer valid. On the basis of Darcy’s low, this paper firstly analyzes the factors that influence the shape of the inflow performance curve, and then discusses the influence of deformable porous medium on IPR formula, and finally establishes a new equation of inflow performance curve of oil well. Furthermore, the regularity of changes of the curve shape with individual parameters is probed, and method for calculating the maximum oil production point is provided. Analysis shows that the equation theoretically explains the deflection and the maximum oil production point, and that it can be used to predict inflow behavior of oil well under different flowing pressures.

Key words: deformable porous media, productivity index, oil well performance, bottom-hole pressure, Inflow Performance Relationship