Granted Patent
Utility
US 4,525,522 · App. 06/416,935
Drilling fluids based on sulfonated thermoplastic polymers having improved low temperature rheological properties
Inventors:
S. Richard Turner, Thad O. Walker, Dennis G. Peiffer, Robert D. Lundberg
Patented Case
View Patent ↗
Granted: Jun 25, 1985
Filed: Sep 13, 1982
Inventors
S. Richard Turner
Thad O. Walker
Dennis G. Peiffer
Robert D. Lundberg
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.