Field-wide installation of optical sensing technology yields multi-sensing benefits

In-well optical flowmeters and pressure/temperature gauges at Buzzard Field show they are a viable alternative to traditional methods.

Bob Smith and Mike Hall, Nexen Petroleum UK Ltd.; Andrew Franklin, Espen S. Johansen and Ö. Haldun Ünalmis, Weatherford Intl.

The adoption rate of Optical Sensing Technology (OST) for in-well permanent monitoring has accelerated dramatically since it was first introduced more than 10 years ago. A number of optical sensor types, including pressure, temperature, distributed temperature, seismic and flowmeters, have been commercialized. Although OST has a demonstrated track record and has gained industry acceptance, large-scale, field-wide commercial deployment has been slow.

This article describes an example of field-wide OST deployment and explores initial results after 13 well completions. Multiple in-well sensors were installed in 27 wells of Buzzard Field in the North Sea, operated by Nexen Petroleum UK Ltd. Initial success shows satisfactory performance in all key areas, including data availability, delivery and post-processing.

Since the introduction of fiber optic-based reservoir monitoring systems in 1993, the adoption rate has increased dramatically. Today, most of the common electronic-based measurements for in-well permanent reservoir monitoring have a commercial optical equivalent. Optical monitoring has also added functionality to the previously available toolset through Distributed Temperature Sensing (DTS) and non-intrusive single- and multiphase flowmeters. Presently, the only area that optical sensing has not penetrated is subsea application.

Optical sensing offers a viable alternative to traditional methods of in-well permanent monitoring. However, it has not yet made significant deployment leaps compared to traditional methods. In 2004, this changed when Nexen UK and its partners PetroCanada Energy North Sea, BG Group and Edinburgh Oil and Gas, awarded the Permanent Downhole Monitoring System (PDMS) contract for Buzzard Field.