WORLD’S FIRST ANNULAR BARRIER INSTALLED IN A SUBSEA, DEEPWATER WELL WITHOUT THE USE OF CEMENT

Welltec ANNULAR BARRIER for completions solutions

Background

As wells get deeper and well trajectories get more complex, the challenge to establish effective cement for zonal isolation (ZI) increases. An operator in Latin America was very challenged by the cemented liners in their wells as they could not deliver well barrier isolation and prevent co-mingling production/injection due to the reservoir pressure and ECD’s.

The operator decided to install Welltec® Annular Barriers (WAB®) for ZI between three distinct reservoirs on this carbonate reservoir well.

The WAB’s had to be qualified for the environment and prove life-of-well reliability to the local governmental agency, which required rigorous testing to confirm integrity. The individual components were subjected to repeated cyclic testing, replicating a 30 years life of well simulation with a methodology defined as “Accelerated Life Testing”.

OPERATION

In October 2014, four WAB’s were installed within the deepwater, cementless, below the salt layer well with 9 5/8” liner in 12 ¼” hole to approx. 20,000 ft TVD. The first WAB was set within the 13 3/8” providing a back up to the liner hanger. The other three WAB’s were installed to provide barriers between three distinctive reservoir units.

The production liner was deployed safely and circulated to total depth (TD) where the WAB’s were expanded quickly under surface control. The WAB’s will isolate the reservoirs and since there is no cement they will provide the primary well barrier between the reservoir units over the life of the well.

ACHIEVEMENTS

The operation was a success and the WAB’s will now effectively prevent fluid communication within the different reservoirs. This is confirmed with data being measured by third party pressure sensors placed in all distinct zones, despite undergoing injection and acid stimulation operations.

This application was the world’s first deployment where a liner was installed across multiple reservoir units and no cement
was used for isolation.

The avoidance of cement represents a breakthrough in cost, efficiency and increased performance in well design.

Read more completion cases

The avoidance of cement represents a breakthrough in cost, efficiency and increased performance in well design.