Granted Patent
Utility
US 4,719,021 · App. 06/919,587
Shale-stabilizing drilling fluids and method for producing same
Inventor:
Homer Branch, III
Patented Case
View Patent ↗
Granted: Jan 12, 1988
Filed: Oct 16, 1986
Inventor
Homer Branch, III
Assignee (at issue)
SUN DRILLING PRODUCTS 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.