| 摘要 |
<p>Tubewaves are used to transmit an indication of the depth at which a condition is detected in a well. In particular, the depth is calculated based on the difference in arrival time at the surface of a first tubewave which propagates directly upward in the borehole and a second tubewave which initially travels downward and is then reflected upward. The tubewaves may be generated by a canister designed to implode at a certain pressure. After being introduced into the flowline at an above ground inlet, the canister is carried downhole by gravity and the fluid being pumped. When the canister reaches a depth at which its pressure tolerance is exceeded, it implodes and generates the tubewaves. An analyzer at the surface detects the tubewaves with a hydrophone array and generates a pressure versus depth profile of the well, i.e., one data point for each implosion. Canisters may be acoustically tagged by controlling volume and orifice size in order to generate tubewaves having particular frequency and amplitude characteristics. Canisters may also be configured to produce multiple implosions, e.g., one implosion at each of a selection of different pressures. Canisters may also be equipped with triggering and arming mechanisms, and may generate tubewaves in response to conditions other than a particular pressure.</p> |
