3626482 is referenced by 44 patents and cites 8 patents.

A method by which physical and mechanical characteristics of rocks are measured during drilling, comprises picking up a signal representing the vibrations of a train of rods forming part of drilling gear, selecting the components of the said signal which, after peak-clipping, are in a frequency band which is centered on, and preferably is related to, a characteristic frequency of the tool, establishing from the components thus selected, a value which is representative of the amplitude of the vibrations, and correlating this value with the drilling depth.

Title
Method and apparatus for measuring lithological characteristics of rocks
Application Number
04/868,873
Publication Number
3626482
Application Date
October 23, 1969
Publication Date
December 7, 1971
Inventor
Lutz Jean
Raynaud Michel H
Quichaud Claude Jean
Assignee
Societe Anonyme dite Societe Nationale des Petroles d Aquitaine
IPC
E21b 49/00
E21b 47/00
E21B 12/02
E21B 44/00
E21B 12/00
View Original Source