Granted Patent
Utility
US 5,077,697 · App. 07/513,319
Discrete-frequency multipole sonic logging methods and apparatus
Inventor:
Shu-Kong Chang
Patented Case
View Patent ↗
Granted: Dec 31, 1991
Filed: Apr 20, 1990
Inventor
Shu-Kong Chang
Assignee (at issue)
Schlumberger Technology 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.