Density measurements using detectors on a pulsed neutron measurement platform

• Main Authors: Gade Sandeep S, Bliven Steven M, Vasilyev Maxim, Chace David M, Inanc Feyzi
• Format: Patent
• Language: English
• Published: 21.03.2017
• Subjects: DETECTING MASSES OR OBJECTS; GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASUREMENT OF NUCLEAR OR X-RADIATION; MEASURING; PHYSICS; TESTING

An apparatus for estimating a property of an earth formation and a borehole fluid includes a carrier configured to be disposed in a borehole, and a pulsed neutron measurement assembly including a pulsed neutron source configured to emit neutrons into the borehole and the earth formation, and a gamma ray detector. The apparatus also includes a fluid density measurement assembly including the gamma ray detector and a gamma ray source configured to irradiate a borehole fluid with gamma rays. The gamma ray detector is positioned relative to the gamma ray source to detect both of: gamma rays resulting from neutron interactions and gamma rays emitted from the borehole fluid in response to irradiation from the gamma ray source. The apparatus further includes a processor configured to differentiate a pulsed neutron gamma ray spectrum associated with the interactions from a density gamma ray spectrum.