Distributed Acoustic Sensing is a novel technology for seismic data acquisition, particularly suitable for Vertical Seismic Profiling. It is a break‐through for low‐cost, on‐demand, seismic monitoring of reservoirs, both onshore and offshore. In this article we explain how Distributed Acoustic Sensing works and demonstrate its usability for typical Vertical Seismic Profiling applications such as checkshots, imaging, and time‐lapse monitoring. We show numerous data examples, and discuss Distributed Acoustic Sensing as an enabler of seismic monitoring with 3D Vertical Seismic Profiling.

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Distributed acoustic sensing is an emerging technology using fibre‐optic cables to detect acoustic disturbances such as flow noise and seismic signals. The technology has been applied successfully in hydraulic fracture monitoring and vertical seismic profiling. One of the limitations of distributed acoustic sensing for seismic recording is that the conventional straight fibres do not have broadside sensitivity and therefore cannot be used in configurations where the raypaths are essentially orthogonal to the fibre‐optic cable, such as seismic reflection methods from the surface. The helically wound cable was designed to have broadside sensitivity. In this paper, a field trial is described to validate in a qualitative sense the theoretically predicted angle‐dependent response of a helically wound cable. P‐waves were measured with a helically wound cable as a function of the angle of incidence in a shallow horizontal borehole and compared with measurements with a co‐located streamer. The results show a similar behaviour as a function of the angle of incidence as the theory. This demonstrates the possibility of using distributed acoustic sensing with a helically wound cable as a seismic detection system with a horizontal cable near the surface. The helically wound cable does not have any active parts and can be made as a slim cable with a diameter of a few centimetres. For that reason, distributed acoustic sensing with a helically wound cable is a potential low‐cost option for permanent seismic monitoring on land.

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A permanent reservoir monitoring system has been installed on an onshore heavy oil field in the context of redevelopment planned for the coming years. The challenge was to continuously monitor with seismic reflection the lateral and vertical expansion of the steam chest injected in the reservoir during production over a year. We show that the very high sensitivity of our buried acquisition system allows for the detection and mapping of tiny changes within the reservoir on a daily basis: we measure a 6 s time shift and a 0.1% amplitude variation per day. The values obtained from seismic monitoring fit the pressure variations measured at observation and production wells. These results confirm that the steam does not follow the expected path to the producer wells.