NEUTRON MEASUREMENT METHOD FOR DETERMINING POROSITY OF A FORMATION SURROUNDING A BOREHOLE

摘要

The invention concerns a neutron measurement method for determining porosity of an earth formation surrounding a borehole comprising:conveying a tool along said borehole, wherein said tool comprises a source of neutron radiation and at least one detector axially spaced from said source;generating measured detector response for said at least one detector that is indicative of neutron radiation from said source interacting with said earth formations;operating said measured detector response with a predetermined mathematical equation and thereby obtaining corrected detector response that is independent of the density of said earth formation; anddetermining porosity of the earth formation surrounding the borehole from said corrected detector response. The invention also relates to a system implementing said method.