Optoelectric permanent downhole cable

Applications

• Survey of multiphase flow profiles during production or injection, in conjunction with Optiq™ fiber-optic solutions
• Borehole seismic surveys via optical vertical seismic profiles (VSPs)
• Optimization and diagnostics of gas lift systems
• Monitoring of tubing and completion equipment for leak integrity and flow assurance
• Monitoring of mudline-to-riser temperature profiles for riser integrity
• Detection of frac hits during hydraulic fracturing
• Provision of redundancy through simultaneous optical and electrical measurements
• Powering Electris™ completions

Benefits

• Reduces costs and complexity with a single cable for electrical and fiber-optic sensors
• Enables better understanding of the well and enhanced production and reservoir characterization through the combination of pressure, distributed temperature, and distributed acoustic measurements
• Enhances safety because it enables monitoring casing deformation and well integrity
• Helps improve production management with real-time measurements that provide immediate indication of changing downhole conditions
• Provides long-term reliability with field-proven Metris™ permanent monitoring systems and Intellitite™ downhole dual-seal dry-mate connectors

Features

• Survey and diagnostic services adaptable to project requirements
• Multiple fibers per cable—for distributed temperature, acoustic, and strain sensing
• Fiber-optic line able to operate independently of electrical downhole gauges
• Minimal impact on completion, wellhead interface, and installation procedures
• Qualified for corrosive environments through rigorous testing

How it improves performance

The SLB optoelectric permanent downhole cable encapsulates an electrical conductor and a metal tube with up to three optical fibers. It enables actuating Electris interval control valves and multidropping permanent downhole gauges belonging to the family of Metris permanent monitoring systems for acquisition of pressure and temperature data. At the same time, the optical fibers enable distributed temperature, acoustic, and strain sensing (DTS, DAS, and DSS)—all with one 1/4-in control line. The combination helps improve well productivity by identifying trends throughout the producing life of the well.

DTS data are typically used for allocation of injection or production and for optimization and diagnostics of the upper completion. DAS data are used for VSPs, leak detection, and analysis of flow properties. DSS enables monitoring well integrity and casing deformation; it is also used to detect frac hits during hydraulic fracturing.

Together, the DTS and DAS data obtained from the optical fibers and pressure and temperature measurements from the gauges provide a more thorough understanding of the reservoir than either technology would provide individually. For example, the data enable accurate diagnostics on gas lift systems, with the added capability of quickly identifying a faulty valve or unstable flow. In addition, the temperature profile along the tubing can be used to identify conditions such as loss of sealing integrity. In many cases, the optoelectric cable can be extended across the reservoir to establish inflow and outflow contributions (and hence monitor interval control valve performance) from the temperature profile and pressure data.

A special wellhead outlet for splitting the electric and fiber-optic lines is also available. The reliability of downhole electrical connections is ensured by the field-proven Intellitite downhole dual-seal dry-mate connector.

How it works

Electric and fiber-optic pathways
All Metris system gauges can operate using the electrical conductor. The optical fibers operate independently of the electrical conductor and do not affect its reliability. The SLB optoelectric cable is externally identical to a standard permanent downhole cable and no modification to the gauge monitoring system is required.

Distributed logging
One optical fiber provides temperature measurements every 0.5 m [about 1.6 ft] along its length, producing a profile of temperature effects along the production string and—when applicable—across the mudline. The fiber-optic line can be interrogated on a continuous or intermittent basis to provide rapid wellsite diagnostics without interfering with production. In addition to DTS, the optoelectric cable enables DAS and DSS. At the surface, data can be transmitted to multiple remote locations via cable or wireless technologies.

Improved production and reservoir management
Optiq real-time fiber-optic interpretation and analysis uses proprietary SLB algorithms and dynamic well models to analyze raw DTS, DAS, DSS, and gauge data in real time. Subsequently, a cloud or web interface presents actionable insights via an intuitive platform that is accessible from anywhere. Faster access to insights empowers immediate action, avoiding costly delays.