Tube wave generation

A method to generate a tube wave in a pressurized tubular system, comprising:

• (a) establishing fluid communication to equalize pressure between a fluid-filled, pressurized tubular system and an enclosed chamber system containing the fluid;
• (b) isolating the enclosed chamber system from the tubular system;
• (c) changing the pressure of the fluid in the isolated, enclosed chamber system;
• (d) reestablishing fluid communication between the enclosed chamber system to equalize the pressure and generate a tube wave;
• and
• (e) guiding the tube wave to the tubular system.

A tube wave generator-sensor system, comprising:

• (a) an enclosed fluid chamber system;
• (b) a plunger slidable through a seal into the chamber system;
• (c) a driver to reciprocate a fluid end of the plunger toward and away from the seal;
• (d) a two-way fluid flow passage to guide a tube wave signal between the chamber system and a tubular system;
• (e) a firing valve to selectively open and close the two-way passage;
• and
• (f) a sensor to receive the tube wave signal, a response to the tube wave signal, or a combination thereof from the tubular system.