A method for monitoring well operations comprises sensing oscillations occurring in the well during a well operation and generating a signal indicative of the oscillations. The signal is processed into sensed data indicative of the oscillations sensed in the well, and the sensed data is then compared with reference data associated with previously detected well operations, to identify the well operation that generated the sensed oscillations. The system that performs the well monitoring, comprises one or more transducers configured to sense the oscillations, and a processing system in communication with the transducer which identifies the well operation and the device that caused the oscillations, based on comparisons of data indicative of the oscillations, with reference data associated with previously detected well operations.