Granted Patent
Utility
US 5,208,216 · App. 07/906,560
Acrylamide terpolymer shale stabilizing additive for low viscosity oil and gas drilling operations
Inventors:
C. Darwin Williamson, Dodd W. Fong, Robert K. Gabel
Patented Case
View Patent ↗
Granted: May 4, 1993
Filed: Jun 30, 1992
Inventors
C. Darwin Williamson
Dodd W. Fong
Robert K. Gabel
Assignee (at issue)
Nalco Chemical Company
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.