Estimating properties of a subterranean formation

A method of operations in a wellbore comprising:

• generating an acoustic signal in a subterranean formation that circumscribes the wellbore;
• obtaining a characteristic of the acoustic signal;
• and
• excavating in the formation by operating a bit at a designated parameter that is based on the characteristic of the acoustic signal;
• wherein the step of excavating comprises radially displacing the bit into impact with the sidewall of the wellbore, conducting coring operations with the bit by rotating the bit, and reciprocating the bit in a plane that is substantially parallel with and spaced radially away from an axis of the wellbore.

A system for use in a wellbore comprising:

• a coring bit that selectively engages a sidewall of the wellbore;
• an acoustic sensor spaced away from the coring bit, and that selectively senses acoustic signals generated by the coring bit engaging the sidewall and that propagate in a formation adjacent the sidewall;
• and
• a processor that is in communication with the acoustic sensor and that selectively estimates a property of the formation based on a characteristic of the sensed acoustic signal, the processor selectively operating the coring bit at a designated parameter based on the estimated property of the formation;
• wherein the bit radially impacts the sidewall of the wellbore, rotates, and reciprocates in a plane that is substantially parallel with and spaced radially away from an axis of the wellbore.