SLB Improves Heavy Oil Recovery with WellWatcher Technology

Schlumberger today introduced its new WellWatcher BriteBlue harsh environment multimode fiber and WellWatcher Ultra distributed temperature acquisition system.

The WellWatcher BriteBlue harsh environment multimode fiber can be used as a distributed sensor for applications such as Distributed Temperature Sensing or for high-speed communication between downhole sensors and a surface acquisition unit. The new generation fiber was designed especially for use in extreme heat and hydrogen environments¬environments that can cause most optical fibers to degrade in physical integrity and performance over time. The new design and technology makes WellWatcher BriteBlue particularly suitable for thermal heavy oil recovery applications.

"The advanced technologies of WellWatcher BriteBlue and WellWatcher Ultra ensure that all system components withstand the challenge of extended harsh environments to deliver the data and answers operators need to make better decisions in real time," said Gabriel Tirado, business development manager-monitoring, Schlumberger Completions. "Permanent in-well reservoir monitoring with WellWatcher is crucial for operators to improve production management and recovery, and identify and resolve problems quickly to reduce downtime and related costs."

The WellWatcher Ultra distributed temperature system surface unit acquires downhole temperature profiles. The versatile new system can measure up to 15 km (9.32 mi) of fiber at a meter's resolution, update data in just a few seconds, resolve temperatures to 0.01 degC, and interrogate numerous fibers from one surface system. As soon as the measurement is taken, the data are available for downstream applications and are communicated using various industry-standard or customized protocols. With new architecture, design and manufacturing methods, the unit is rugged, thereby extending its life and making it better suited for both permanent monitoring and intervention techniques in all environments.

Extensive field testing of both the WellWatcher BriteBlue and WellWatcher Ultra technologies was performed in the U.S. and Canada in extremely high temperatures (downhole temperature greater than 250 degC). These tests positively demonstrated no discernible reduction in fiber or measurement performance and provided users with far more insight into the zones contributing the most to a well's production during transient conditions.

Schlumberger has been successfully installing WellWatcher BriteBlue in the harsh conditions of heavy oil thermal recovery wells in Canada since April 2007. These wells can reach temperatures as high as 300degC and can provide a real challenge for fiber survivability. One injection well in particular that is often run at temperatures around 300degC had rendered the previously best available fiber unusable through hydrogen degradation in less than a month. This fiber was replaced to WellWatcher BriteBlue in September 2007 and to this day shows no signs of degradation.