DAS interrogation equipment (DK5.2)

Equipment for DAS interrogation

GEUS possesses two DAS interrogators and several kilometres of armed fibre optic cabling. A small trenching machine for deploying cable in the field is also part of the facility. The setup measures strain in (trenched) optical fibre, relevant for baseline monitoring and induced seismicity. The facility can also be used for active and passive seismic surveying.
GEUS has experienced staff able to undertake cable deployment, collection of data plus subsequent processing and analysis using inhouse software.

2 Interrogators:

ASN OptoDAS C01-S
Maximum offset: 200 km
Spatial resolution: Down to 2 m
Sampling frequency: 500 Hz – 100 kHz
Signal wavelength: 1536.61 nm
GPS time
Weight: 60 kg (including server and flight case)
Dimensions: 0.5*0.7*0.7 m

including complete toolkit for cleaning, servicing, fibre splicing, and link-testing

Cables:
4 * 1000 m drums of armed single-mode optical fibre cable (SC-UPC)

3 * 50 km coils of unjacketed single-mode optic fibre for lab testing

Trenching machine:
Bernards Baumaschinen KAB45
Maximum trenching depth: 45cm
Weight: 150 kg

The DAS system is based at GEUS, the largest institution for geoscience in Denmark, which holds a broad range of expertises relevant for, e.g. CO2 storage, incl. seismic interpretation with well-ties, stratigraphic/biostratigraphic analyses, flow experiments on core samples, geological interpretation, static and dynamic reservoir modelling, plume migration, monitoring for induced seismicity, land uplift, and groundwater.

A versatile facility, the DAS interrogator setup makes for very dense (spatially and temporally) seismic data acquisition with highly customizable survey design, i.e. a fibre cable can be laid in patterns fit for the specific project. A monitoring survey that utilizes DAS may replace the use of multiple seismic stations.