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

Claim 0:
1. A system for determining depths of subterranean formation layer tops while drilling through the subterranean formation, the system comprising:
a drill bit operable to drill a bore into one or more layers of subterranean formation;
a drill rig comprising one or more drilling motors operable to control the depth and rotation of the drill bit into the subterranean formation;
a microphone attached to the drill bit and operable to measure sound at a plurality of depths while drilling the bore;
a depth sensor operable to measure a drill bit depth at the plurality of depths while drilling the bore; and
a processor electrically connected to the microphone and the depth sensor, the processor operable to perform operations while drilling, the operations comprising:
receiving, from the microphone, a sound signal representing sound measured at a plurality of depths within the bore;
receiving, from the depth sensor, a depth signal representing the drill bit depth at the plurality of depths within the bore;
normalizing the measured sound across the plurality of depths based on the sound signal and the depth signal;
determining frequency spectrums of the normalized sound for one or more depths of the plurality of depths, each frequency spectrum representing spectral amplitude versus frequency;
transforming the frequency spectrums into a single depth spectrum representing the spectral amplitude versus depth for a particular frequency between 100 Hz and 400 Hz;
determining the depths of subterranean formation layer tops based on the depth spectrum;
determining a control signal for the one or more drilling motors of the drill rig based on the determined one or more depths; and
transmitting the control signal to the one or more drilling motors of the drill rig for controlling at least one of the depth and the rotation of the drill bit.