Granted Patent
Utility
US 4,301,016 · App. 06/008,758
Borehole drilling fluid and method
Inventors:
David B. Carriere, Rodrigue V. Lauzon
Patented Case
View Patent ↗
Granted: Nov 17, 1981
Filed: Feb 2, 1979
Inventors
David B. Carriere
Rodrigue V. Lauzon
Assignee (at issue)
NL Industries, Inc.
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.