Granted Patent
Utility
US 4,836,940 · App. 07/095,638
Composition and method of controlling lost circulation from wellbores
Inventor:
William Alexander
Patented Case
View Patent ↗
Granted: Jun 6, 1989
Filed: Sep 14, 1987
Inventor
William Alexander
Assignee (at issue)
American Colloid 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.