Paper Summary

Permanent reservoir monitoring (PRM) using seabed arrays of seismic sensors is becoming a well recognised tool for optimizing production and increasing reserves at lower cost and risk through improved reservoir management. An approach based on fully fibre-optic sensors offers significant benefits in terms of long term reliability and reduced through-life costs. A successful PRM system will also require high stability of the output seismic data in terms of sensitivity, noise and other key performance attributes throughout its operating lifetime. We discuss issues which affect system stability, and describe how we have addressed these through a combination of careful system and mechanical design based on over 25 years experience of analogous systems and rigorous qualification, demonstrating over 30 years’ equivalent accelerated sensor lifetime without performance change. We present results from two field tests, 3 years apart, to show that highly stable sensor operation can be achieved in real field environments.