Granted Patent
Utility
US 6,143,699 · App. 08/760,573
Process for reducing permeability in a subterranean formation
Inventor:
Zhihong Zhou
Patented Case
View Patent ↗
Granted: Nov 7, 2000
Filed: Dec 4, 1996
Inventor
Zhihong Zhou
Assignee (at issue)
Alberta Oil Sands Tech and Research Authority
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.