Granted Patent
Utility
US 4,425,462 · App. 06/416,937
Drilling fluids based on sulfonated elastomeric polymers
Inventors:
S. Richard Turner, Robert D. Lundberg, Thad O. Walker
Patented Case
View Patent ↗
Granted: Jan 10, 1984
Filed: Sep 13, 1982
Inventors
S. Richard Turner
Robert D. Lundberg
Thad O. Walker
Assignee (at issue)
Exxon Research and Engineering 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.