| 摘要 |
<p>A system for sensing subterranean acoustic waves emitted from an acoustic source includes a plurality of laser sources (LS1-LS6), a plurality of subterranean optical sensors (1000), at least one optical detector (D1-D16), and electronics (601). The laser sources each emit light at a different frequency. The subterranean optical sensors are hydrophones (1000) that receive the light and alter the light in response to the acoustic waves. The optical detector (D1-D16) receives the altered light and outputs an electrical signal. The electronics (601) receives the electrical signal and converts it into seismic data format. The hydrophones (1000) are able to operate at pressures of at least 5,000 psi and temperatures of at least 130 degrees Celsius. The hydrophone (1000) may be housed in a cable (1002) having a diameter of less than about 1.5 inches. The hydrophone's sensor preferably includes a reference mandrel (1110), two sensing mandrels (1120), and a telemetry can (1104), all of which are aligned in a coaxial, end-to-end configuration to reduce the profile of the hydrophone (1000). Flexible interlinks (1296) having grooves therein for receiving optical fiber join the mandrels (1110, 1120) together. The reference mandrel (1110) and sensing mandrels (1120) advantageously have hemispherically-shaped endcaps (1264), permitting them to operate at high pressure. <IMAGE></p> |
