Laboratory testing of low frequency strain measured by distributed acoustic sensing

Becker, Matthew W. (California State University Long Beach) | Ciervo, Christopher (California State University Long Beach) | Coleman, Thomas (Silixa LLC)


Summary Recent field experiments have demonstrated that distributed acoustic sensing (DAS) can be used to record strain in fiber optic cable at mHz frequencies. However, the effect of fiber optic cable construction on strain transfer has not been evaluated. The laboratory experiments presented here were designed to mimic fiber optic cable cemented into a borehole that intersects bedrock fractures. Hydraulic stress on the fracture is expected to stretch the cemented borehole which can be sensed by DAS. In the laboratory, we cemented five different fiber optic cable constructions into a pipe and then strained the pipe periodically using stepper motors.