Granted Patent
Utility
US 4,280,915 · App. 05/809,369
Salt stable lubricant for water base drilling fluids
Inventor:
James D. Kercheville
Patented Case
View Patent ↗
Granted: Jul 28, 1981
Filed: Jun 23, 1977
Inventor
James D. Kercheville
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.