Granted Patent
Utility
US 5,988,278 · App. 08/982,574
Using a horizontal circular wellbore to improve oil recovery
Inventor:
Mark Johnson
Patented Case
View Patent ↗
Granted: Nov 23, 1999
Filed: Dec 2, 1997
Inventor
Mark Johnson
Assignee (at issue)
Atlantic Richfield 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.