Wavefield characterization of perforation shot signals in a shale gas reservoir

The six modes include P- & S-waves converted from tube waves in the shot (treatment) well at plugs or the well bottom, an up-going tube wave in the monitoring well generated by the tube wave in the nearby treatment well, a down-going tube wave from the treatment wellhead and the multiple, a scatting body wave activated by tube waves in the treatment well. These wave modes all originate from the waves radiated at the perforation point in the treatment well as tube waves and are then radiated into the formation and received by geophones in the nearby borehole as P, S, or tube waves. If energy from the perforation shot is strong enough, the tube wave will turn back from the surface and be reflected at the well bottom or plugs, which would excite the further waves. Based on the features of the wavefield, we identify the perforation events and facilitate better use of calibration from the perforation seismic recording for microseismic data processing. We also evaluate attenuation of the signals with propagation distance and propose a procedure for developing a plan for monitoring of perforation and string shot signals.