Measurement of formation porosity using a single gamma ray detector

摘要

A pulsed neutron source is used in a porosity logging tool with a single gamma ray detector coated with a neutron absorbing material. By using a ratio of the spectral peak associated with hydrogen to a spectral peak associated with the neutron absorbing material, the formation porosity is estimated.

主权项

1. A method of evaluating an earth formation, the method comprising:
obtaining an indication of a porosity of the earth formation using gamma rays measured by a single gamma ray detector, where the earth formation has been irradiated by a neutron source and the single gamma ray detector is coated with a neutron absorbing material.