Patents by Inventor E. Frederic Riedel

E. Frederic Riedel has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Tracing flow of petroleum in underground reservoirs
    Patent number: 3993131
    Abstract: The flow path of petroleum in underground reservoirs is monitored by injecting a stable free radical, or spin label, into the reservoir as a tracer which becomes detectable in a sample taken from a producing well. Detection of the spin label is by electron spin resonance (ESR) spectroscopy. Spin label tracers are, on the average, detectable at dilutions 1 million times lower than is possible with standard chemical tracing methods.
    Type: Grant
    Filed: November 3, 1975
    Date of Patent: November 23, 1976
    Assignee: Cities Service Company
    Inventor: E. Frederic Riedel