SPECIFIC FEATURES OF THE DISPLACEMENT OF LIQUID DURING FILTRATION IN A LOW-POROSITY MEDIUM

The work is devoted to the study of the displacing ability of porous media in extraction of hydrocarbons from the
latter. Using the laws of mass and momentum conservation, the expression for the coeffi cient characterizing the
displacing ability of the medium in the resilient mode of deposit exploitation has been refi ned. It is shown that the
found expression diff ers from the classical concepts, as well as from the value of the compressibility coeffi cient of the
porous medium in the fi ltration approximation. It has been established that, in the general case, the compressibility
of a porous medium includes terms that depend not only on the macroscopic characteristics, but also on the
microstructure of the porous medium. Criteria are determined, under which the elastic properties of the medium do
not depend on its microstructure: when the densities of the liquid and of the skeletal material are equal and when the
porosity is independent of pressure, then the pore structure does not aff ect the compressibility of the porous medium.
Various physical conditions of the process are identifi ed, when it is necessary to introduce special concepts of
compressibility.
It is shown that when the porosity decreases to zero, the value of the coeffi cient characterizing the displacing
ability of the medium reaches the values that signifi cantly exceed the compressibility of the liquid. At the same
time, as the porosity tends to unity, this coeffi cient tends to the value of liquid compressibility. This behavior of the
coeffi cient indicates the existence of a physical eff ect consisting in the predominant contribution of skeletal material
deformation to the displacement process in the areas of the reservoir of oil and gas with a reduced porosity
   
Author:  A. I. Filippov ,  P. N. Mikhailov
Keywords:  elastic medium, compressibility of a two-phase system, conservation laws, pressure, porosity, density
Page:  721