Granted Patent
Utility
US 5,977,031 · App. 09/130,914
Ester based invert emulsion drilling fluids and muds having negative alkalinity
Inventor:
Arvind D. Patel
Patented Case
View Patent ↗
Granted: Nov 2, 1999
Filed: Aug 7, 1998
Inventor
Arvind D. Patel
Assignee (at issue)
M-I L.L.C.
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.