Abstract
When a pulsed neutron tool (PNT) is fired, on the order of 1e8 neutrons per second are produced. Each of these neutrons carries 14.1MeV of kinetic energy. This energy is largely deposited in neighboring materials through inelastic scattering. This results in a large amount of ionization in the surrounding materials. A large number of the electrons liberated in this process have kinetic energies that are large when compared to the electron’s rest mass making them fairly relativistic. If these relativistic electrons propagate inside a transparent material, such as oil or water, they will radiate photons through a process called Cerenkov radiation. These Cerenkov photons feature a broadband spectrum that is peaked at ultraviolet (UV) wavelengths but contains a significant tail even down to infrared wavelengths. This infrared light (IR) can be used to determine the type of fluid that the electrons are traveling through since IR wavelengths have chemical dependent absorption spectra that act like a fingerprint for distinguishing different chemicals. By analyzing light at a few IR wavelengths that are sensitive to OH-bond absorption and CH-bond absorption, it should be possible to measure an oil-water ratio based on Cerenkov light created by a PNT.
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Recommended Citation
"Cerenkov-based borehole fluid characterization tool", Technical Disclosure Commons, ()
https://www.tdcommons.org/dpubs_series/9553