Granted Patent
Utility
US 4,657,948 · App. 06/779,140
Fluid loss control in well cement slurries
Inventors:
David N. Roark, Adam T. Nugent, Baldev K. Bandlish
Patented Case
View Patent ↗
Granted: Apr 14, 1987
Filed: Sep 23, 1985
Inventors
David N. Roark
Adam T. Nugent
Baldev K. Bandlish
Assignee (at issue)
Ethyl Corporation
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.