By John Hunter, Advanced Completions Director and Kevin Buchan, Advanced Completions Application Engineer

Wireless completions equipment is becoming increasingly more common, from Drill Stem Testing (DST) to multi-node intelligent completions. The move from conventional equipment with no communication mechanism, and more modern control line based systems, to a wireless system is ongoing, and presents several key advantages in efficiency, performance and safety.

All completions incur significant costs, but one of the key items, when used, is the control line for downhole communication and actuation. At many Dollars per ft, even single control line strings can add significant cost to the project, with triple or more bundles for hydraulic control adding over $1mill to the project cost once the additional hardware, man-power and rig time are included.

While control line systems typically require increased CAPEX, the alternative of a conventional completion system can often see the savings on equipment nullified due to increases in OPEX and deferred production through increased intervention and poor reservoir performance.  The addition of real-time data can lead to informed decision-making, while the ability to act immediately and without intervention leads to an optimal production environment.

Wireless systems can help to provide a hybrid of the key features, whereby the completion is kept simple.  This allows a quick and safe installation, while offering the communication mechanism required to monitor and control wells effectively.

Installation

Wireless devices by nature are standalone units, and require minimal installation time and rig floor presence.

One of the major benefits that wireless systems offer over control line systems is improved barrier integrity. This is achieved by removing the need for cable feedthroughs in hangers and packers, thus significantly reducing the number of potential leak paths. Control lines also pose an issue for workovers, with added cost and time to ensure all are recovered and out-with the cemented pressure barrier zone.

For hydraulically controlled systems, a large footprint of equipment is needed on the platform, which in turn may pose a challenge when planning the design of the topsides. Wireless systems have no requirement for any additional large topside system. Electromagnetic/Radio frequency or Acoustic-based systems require small control modules, whereas pressure pulse systems utilise existing wellhead equipment. Again, decommissioning large, heavy plant equipment poses issues.

Although a wireless completion is often as simple as a conventional one in terms of make-up and deployment, wireless systems can offer additional benefits during Run in Hole and landing out of the string by providing active fluid control.

Operation

Without the need for control lines or intervention access to operate, devices can be placed in almost all areas of a completion, an example being multiple devices along the lateral in a complex multilateral well. Having close and detailed control facilitates increased reservoir contact and enhanced recovery.

In addition, to function wirelessly, systems need a degree of inbuilt intelligence, lending themselves to operating with more autonomy. Examples include devices that can detect changes such as well shut-ins and react as planned, or devices with set time actuations, for instance pressure and temperature data or to sync with other operations.

Most wireless equipment can be retrofitted as and when required by using standard intervention techniques. This highlights the suitability of installing wireless equipment later in the life of a well, whether that be to recover the functionality of failed equipment or add in monitoring and control to wells that had none.

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