Tube-wave seismic imaging

A method for seismic imaging using tube-waves, the method comprising the steps of:

• a) transmitting an input tube-wave waveform down a transmitter borehole;
• b) coupling the input tube-wave waveform through a perforation in the transmitter borehole and into a geological mass outside the transmitter borehole as a converted laterally propagating signal tube-wave waveform that propagates within the geological mass;
• c) receiving the converted laterally propagating signal tube-wave waveform that propagated through the geological mass at a receiver borehole, and coupling the received converted laterally propagating signal tube-wave waveform into the receiver borehole as a received tube-wave waveform;
• and,
• d) digitally processing the received tube-wave waveform to produce a seismic image of said geological mass disposed between said transmitter and receiver boreholes,
• wherein said receiving step and said coupling step for said received tube-wave waveform occurs after the arrival of an initial P wave through said geological mass in traditional seismic imaging.

A method for seismic imaging using tube-waves, the method comprising the steps of:

• a) transmitting an input tube-wave waveform down a transmitter borehole;
• b) coupling the input tube-wave waveform through a perforation in the transmitter borehole and into a geological mass outside the transmitter borehole as a converted laterally propagating signal tube-wave waveform that propagates within the geological mass;
• c) receiving said converted laterally propagating signal tube-wave waveform that propagated through the geological mass at a receiver borehole, and coupling the received converted laterally propagating signal tube-wave waveform into the receiver borehole as a received tube-wave waveform;
• and,
• d) providing means for digitally processing the received tube-wave waveform to produce a seismic image of a geological mass disposed between said transmitter and receiver boreholes,
• wherein said receiving step and said coupling step for said received tube-wave waveform occurs after the arrival of an initial P wave through said geological mass in traditional seismic imaging.

An apparatus for seismic imaging using tube-waves, the apparatus comprising:

• a) a transmitter borehole positioned down into a geological mass so an input tube-wave waveform can be transmitted down said transmitter borehole, and at least one perforation being positioned in said transmitter borehole so the input tube-wave waveform can be coupled into a geological mass outside the transmitter borehole as a converted laterally propagating signal tube-wave waveform that propagates through the geological mass;
• b) a receiver borehole positioned down into a geological mass at a distance from said transmitter borehole, said receiver borehole positioned to receive the converted laterally propagating tube-wave waveform that propagated through the geological mass;
• c) a receiver tube-wave converter that couples the received converted laterally propagating tube-wave waveform into a received tube-wave waveform after the arrival of an initial P wave was transmitted through said geological mass in traditional seismic imaging;
• and
• d) digital processing means for using the received tube-wave waveform to produce a seismic image of the geological mass disposed between said transmitter borehole and said receiver borehole.