 | This article may be too technical for most readers to understand.(June 2012) |
In petroleum engineering, the Leverett J-function is a dimensionless function of water saturation describing the capillary pressure, [1]
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where is the water saturation measured as a fraction, is the capillary pressure (in pascal), is the permeability (measured in m²), is the porosity (0-1), is the surface tension (in N/m) and is the contact angle. The function is important in that it is constant for a given saturation within a reservoir, thus relating reservoir properties for neighboring beds.
The Leverett J-function is an attempt at extrapolating capillary pressure data for a given rock to rocks that are similar but with differing permeability, porosity and wetting properties. It assumes that the porous rock can be modelled as a bundle of non-connecting capillary tubes, where the factor is a characteristic length of the capillaries' radii.
This function is also widely used in modeling two-phase flow of proton-exchange membrane fuel cells. [2] A large degree of hydration is needed for good proton conductivity while large liquid water saturation in pores of catalyst layer or diffusion media will impede gas transport in the cathode.
