ACOUSTICALLY ENHANCED OPTICAL CABLES

摘要

Methods and apparatus to control the acoustic properties of optical cables used as in-well oil and gas probes for acoustic monitoring, such as distributed acoustic sensing (DAS). One example aspect provides a solid path for the acoustic wave to propagate from an outside armor layer of the cable to the sensing optical waveguide embedded therein. Another example aspect offers ways to spatially dispose the optical sensing elements to create response delays indicative of the propagation speed and/or direction of an acoustic wave. Yet another example aspect provides ways to utilize additional spectral interrogation to increase ultimate spatial resolution. Yet another example aspect provides ways to locally vary the acoustic properties along the length of the cable.