Granted Patent
Utility
US 5,134,215 · App. 07/598,059
Method for reducing fluid loss from oilfield cement slurries using vinyl grafted wattle tannin
Inventors:
David A. Huddleston, Robert K. Gabel, Charles D. Williamson
Patented Case
View Patent ↗
Granted: Jul 28, 1992
Filed: Oct 15, 1990
Inventors
David A. Huddleston
Robert K. Gabel
Charles D. Williamson
Assignee (at issue)
Nalco Chemical 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.