Downhole acoustic systems and related methods of operating a wellbore

A method of operating a wellbore, the method comprising:

• providing a drill string including a drill bit configured to drill through a subterranean formation in a wellbore in association with an array of acoustic emission transducers;
• coupling the array of acoustic emission transducers to a controller comprising a processor including a memory having stored thereon an acoustic pattern for events corresponding to a fracture of the subterranean formation, a cutting operation of the drill bit, corrosion of the drill string, corrosion of the drill bit, an amount of fracturing of the drill bit, and gas ingress into the wellbore;
• detecting acoustic emissions originating within the wellbore with the array of acoustic emission transducers;
• using the processor to generate an acoustic waveform corresponding to the acoustic emissions within the wellbore;
• and
• providing an indication of at least one condition or characteristic of a component or material within or adjacent to the wellbore responsive to at least a portion of the acoustic waveform substantially corresponding to an acoustic pattern stored in the memory.

A downhole acoustic system, comprising:

• one or more acoustic emission transducers operably coupled to a member of a drill string including a drill bit and configured to sense acoustic emissions associated with one or more acoustic events selected from the group consisting of a fracture of the formation, a fracture of the drill bit, a fracture of a cutting element of the drill bit, rubbing of the drill bit, corrosion of the drill string, corrosion of the drill bit, and gas ingress into a wellbore;
• and
• a controller comprising a processor including a memory operably coupled to the one or more acoustic emission transducers and configured to:
• determine one or more of a frequency of the acoustic emissions, an amplitude of the acoustic emissions, an energy of the acoustic emissions, a duration of the acoustic emissions, a rise time of the acoustic emissions, and a frequency centroid of the acoustic emissions;
• and
• provide an indication of at least one of the acoustic events responsive to at least a portion of the acoustic emissions exhibiting a substantially similar acoustic pattern as an acoustic pattern stored in the memory.