Borehole Optical Seismic System (BOSSTM)

BOSSTM is a completely new innovation for Avalon Sciences. The system is entirely passive downhole with sophisticated electronics remaining at the surface in a controlled environment.

The high continuous operational temperature rating (260°C) and solid mechanical coupling system will deliver a long-term deployment solution, ideal for deep-well subsalt 4D VSP and high-resolution fracture monitoring surveys. The bespoke system coupling design and absence of downhole electronics allow for discrete or permanent/semi-permanent operation.

ASL Fibre Systems Brochure

The system has already successfully completed its first commercial surveys in 2021 and 2022.

  • No Downhole Electronics
  • Passive Fibreoptic Borehole System
  • 200°C Continuous Operation
  • 20,000 PSI Pressure Rated
  • High Sensitivity
  • Low Noise

150 Kg Coupling Force on passive arm




The array utilises 3 component optical omni-directional geophones specially developed by Avalon to cope with hostile deep well conditions. These broadband sensors are low noise, extremely sensitive and will work in any orientation from vertical through to horizontal. Sensitivity, noise floor and bandwidth have been optimised to cover both VSP and fracture monitoring.

The system is fully expandable from a small microseismic 8 level system up to 96 stations for large 3D VSPs. The fibreoptic system can also survive more permanent deployment due to metal to metal C-rings throughout, meaning it can be considered for life-of field installations.

The stations are deployed as standard with optical wireline or on jointed or coiled tubing as an option. The array can be spaced at just a few meters or at several hundred meters for total well coverage. Tool coupling can be bespoke, with an option of patent pending non-electrical delayed clamp arm design, giving up to 150kg locking force.


BOSSTM Specifications Up to 100 Receivers
Dynamic Range: >100db
Noise Floor: <50 ng/√Hz
Distortion: <0.01%
Bandwidth: 1-800 Hz
Sensors: Omnidirectional Fibre Optic Accelerometer
Max Temp: 260oC  continuous
Max Pressure: 20,000psi (1400 bar)
Wireline Optical
Control Panels BOSS Interrogator