Granted Patent
Utility
US 4,609,821 · App. 06/608,762
Testing for the presence of native hydrocarbons down a borehole
Inventor:
Charles F. Summers
Patented Case
View Patent ↗
Granted: Sep 2, 1986
Filed: May 9, 1984
Inventor
Charles F. Summers
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.