Granted Patent
Utility
US 4,780,220 · App. 07/053,472
Drilling and completion fluid
Inventor:
Thomas E. Peterson
Patented Case
View Patent ↗
Granted: Oct 25, 1988
Filed: May 26, 1987
Inventor
Thomas E. Peterson
Assignee (at issue)
Hydra Fluids, 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.