Over the past several years, Welltec® Annular Barrier (WAB®) technologies have been a driving force for significant reductions in completion costs and time for operators’ well constructions.

The 812 WAB, a metal expandable packer, was developed because of an industry-wide need for a packer that performs zonal isolation for water-oil contact in open-hole environments. This technology was qualified for various applications in terms of borehole sizes, pressures, and temperatures, including maximum diameters of 10”, high pressure environments, and high temperatures (302°F/150°C).

Recently, in Brazil, Welltec collaborated closely with a client to implement the WAB in a field campaign in a pre-salt field. Equipment was assembled using perfluoro elastomer (FFKM) seals for compatibility with high pressure reservoir and the necessity of the client in using Calcium Bromide (CaBr2) in the composition of the fluid, to increase hydrostatic pressure in the fluid environment of the well.

Welltec deployed two WABs in an 8.5” open-hole completion. The pair of WABs were set apart starting from the bottom to top. The initial challenge involved the placement of the internal string in the seals between the upper and lower seal bore of the WABs. After bleeding pressure to relocate the lower and upper seal bore into optimum positions, the WABs set as planned.

The service string with a Bonded Ported Sub Inflation Tool was placed between seal bores above and below each WAB. The Bonded tool has a by-pass that keeps the well control on the formation while the ported sub communicates with the expansion ports in the WABs to be pressurized.

The WABs were expanded through the cementing unit, pressuring up the internal of service string with flow rate of 0.5 bpm in three steps, reaching 5200 psi of differential pressure. The zonal isolation of the open-hole annular with the deployment of the WABs was acquired successfully.

This job was the first deployment of two WABs for a client in Brazil in an important pre-salt field. The operation was a breakthrough application using the WAB for zonal isolation with FFKM seals in a high-pressure environment and Calcium Bromide (CaBr2) presence.

As a result of this job, the client has offered an important field campaign to Welltec in pre-salt Brazil. This project consists of several wells, both producers and injectors. This successful operation further reinforces the reliability and service quality of Welltec’s innovative completion technologies.