Patent ID: 6032102
Filing Date: 2000-02-29
Classification: G01V

Abstract:
A method for determining the porosity of a geological formation, comprising:generating neutron pulses that release neutrons into a first region and the geological formation surrounding said first region;sensing neutrons and acquiring a plurality of neutron detector count rates using at least two neutron source to neutron detector spacings;acquiring a timing measurement at one of said spacings to measure a first depth of investigation;acquiring a first ratio of said neutron detector count rates to measure a second depth of investigation;calculating an apparent porosity using at least one of said timing measurements and said ratio of neutron count rates;determining the effect of said first region on said calculated apparent porosity in response to at least one of said ratio of neutron detector count rates and said timing measurement;calculating a formation porosity by performing correction to said apparent porosity for the determined effect of said first region.