Granted Patent
Utility
US 4,247,403 · App. 06/050,872
Method of sealing pores, and lost circulation additive therefor
Inventors:
Kevin Foley, David I. B. VanderHooven, Jerry Hull
Patented Case
View Patent ↗
Granted: Jan 27, 1981
Filed: Jun 21, 1979
Inventors
Kevin Foley
David I. B. VanderHooven
Jerry Hull
Assignees (at issue)
The Andersons Inc.
Rotary Drilling Services, Inc.
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.