Patent ID: 11920460
Assignee: SAUDI ARABIAN OIL COMPANY
Field: Civil engineering (Other fields)
Classification: CPC E  G | IPC E

Claim 15:
16. A method for determining depths of subterranean formation layer tops while drilling through the subterranean formation, the method comprising:
drilling, by a drill bit, a bore through one or more layers of the subterranean formation; and
while drilling the bore:
measuring, by a microphone of the drill bit, a sound at a plurality of depths within the bore, the sound produced from an interaction of the drill bit and the subterranean formation;
measuring, by a depth sensor of the drill bit, a drill bit depth at the plurality of depths within the bore;
receiving, by a processor, a sound signal representing the measured sound and a depth signal representing the measured drill bit depth;
normalizing, by the processor, the measured sound across the plurality of depths based on the received sound signal and the depth signal;
determining, by the processor, frequency spectrums of the normalized sound for one or more depths of the plurality of depths, each of the frequency spectrums representing spectral amplitude versus frequency;
displaying, by a user interface, at least two of the frequency spectrums;
in response to displaying the at least two frequency spectrums, selecting, by the user interface, a first frequency range between 0 Hz and 500 Hz;
in response to selecting the first frequency range, determining, by the processor, a second frequency range between 200 Hz and 400 Hz;
transforming, by the processor, the frequency spectrums into a single depth spectrum representing the spectral amplitude versus depth for a first particular frequency of the second frequency range;
displaying, by the user interface, the depth spectrum; and
determining, by the processor, the depths of subterranean formation layer tops based on the depth spectrum;
determining, by the processor, a control signal for one or more motors of a drill rig based on the determined one or more depths; and
controlling, by the one or more motors of the drill rig, at least one of a depth and a rotation of the drill bit based on the control signal.