SYSTEM AND METHOD FOR GENERATING MICRO-SEISMIC EVENTS AND CHARACTERIZING PROPERTIES OF A MEDIUM WITH NON-LINEAR ACOUSTIC INTERACTIONS

摘要

A method and system for generating a micro-seismic event in a medium from a non-linear interaction to characterize the medium is provided. The method includes generating, by a first acoustic source (SI, 12), a first coded acoustic signal comprising a first plurality of pulses arranged as a time sequence, each pulse comprising a modulated signal at a central frequency; and generating, by a second acoustic source (S2,14), a second coded acoustic signal comprising a second plurality of pulses arranged as a time sequence, wherein each pulse comprises a modulated signal and a central frequency of the modulated signal within each pulse in the second plurality of pulses is a selected fraction d of the central frequency of the modulated signal for the corresponding pulse in the first plurality of pulses. The method further includes receiving, by a receiver (R), a detected signal including a third signal being generated by a non-linear mixing process from the first acoustic signal and the second acoustic signal in the mixing zone; performing, by a processor, data processing on the received signal, or correlating with a coded signal template, or both, to extract the third signal generated by the non-linear mixing process over noise or over signals generated by a linear interaction process, or both, to obtain an emulated micro-seismic event signal occurring at the mixing zone; and characterizing properties of the medium or creating a 3D image of the properties of the medium, or both, based on the emulated micro-seismic event signal.