Fiber-Optic Interrogators: DAS or Not DAS? Field and Laboratory Testing

Seismic instrumentation is becoming increasingly diverse. A major milestone has been the emergence of fiber-optic recording systems based on the capability to measure the time-varying strain of an optical fiber cable. The technology is now well developed and available as commercial solutions. The broad class of fiberoptic recorders referred to as DAS (Distributed Acoustic Sensor (Sensing)) includes several operating principles for working with optical fiber, and not all of them can be applied effectively in seismic exploration. In some cases, it is difficult to identify the technical type of the equipment, especially for new developments. In this paper, we demonstrate an example of equipment testing on a physical laboratory bench that could indicate whether the instrument is suitable; however, field tests reveal that the hardware solution is not appropriate for seismic exploration tasks. We emphasize the importance of field validation of equipment prior to deployment and demonstrate the inapplicability of “amplitude” DAS for seismic exploration applications.

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