초록 ▼

The porosity and permeability of a geological formation (2) are determined on the basis of an electrofiltering phenomenon by exploiting the existence of non-linear electrofiltering phenomena. One or two pressure generators (11 ) are used to propagate a pressure wave in the formation. Electrodes (14,

The porosity and permeability of a geological formation (2) are determined on the basis of an electrofiltering phenomenon by exploiting the existence of non-linear electrofiltering phenomena. One or two pressure generators (11 ) are used to propagate a pressure wave in the formation. Electrodes (14, 15) applied against the wall of the formation pick up the electric response of the formation. The detection of a resonance frequency or a phase shift corresponding to an extremum of the electric response of the formation makes it possible to calculate the porosity or permeability of the formation or find their values from charts.

대표청구항 ▼

Method for determining the porosity and/or permeability of a geological formation likely to generate non-linear electrofiltering phenomena from an electrofiltering effect generated in the formation and including stages consisting of: －mechanically and repeatedly exciting a fluid of said formation so

Method for determining the porosity and/or permeability of a geological formation likely to generate non-linear electrofiltering phenomena from an electrofiltering effect generated in the formation and including stages consisting of: －mechanically and repeatedly exciting a fluid of said formation so as to propagate a pressure wave with suitable characteristics for generating an electrofiltering effect in the formation, －measuring a variable representative of an electrofiltering potential generated in the formation by said pressure wave, wherein it further includes stages consisting of: －determining a critical frequency of propagation of the pressure wave by varying a mechanical excitation frequency of the formation and following up the corresponding variation of the variable representative of the non-linear electrofiltering phenomenon, －determining the porosity and/or permeability of the formation on the basis of the relation linking them to said critical frequency.