Dual Neutron Probe
GeoLog Pty Ltd
The dual neutron probe provides an accurately calibrated borehole-compensated neutron porosity measurement in mud-filled open holes. It is the probe of choice for quantitative formation-fluid studies, including shallow oil and gas prospects.
Principles of Measurement
The dual neutron measurement uses two 3He proportional detectors and a detachable, sealed neutron source. Fast neutrons emitted by the source are scattered and slowed by light elements (and principally hydrogen in the formation) until they reach thermal energy levels. The ratio of the flux of thermal neutrons reaching the near and far detectors depends on the Hydrogen Index and porosity. Use of the two detectors and a ratio method provides a porosity measurement which is independent of borehole size over a range of hole diameters.
Wide porosity range (0 to 60% sandstone equivalent)
Compensation for borehole diameter using dual detectors
Real-time porosity measurement with Videologger and Micrologger systems
Option of natural gamma for correlation
Option of CCL for casing inspection
Raw long-spaced neutron
Raw short-spaced neutron
Casing collar locator