Minimize rig time during well test in presalt environment

When operating a vertical oil well offshore Angola at 923-m water depth, Cobalt International Energy wanted to minimize rig time and associated costs during a deepwater presalt well test without sacrificing safety and quality. Cobalt also wanted to reduce rig time required to conduct the well test while ensuring the downhole tools were not damaged due to the operating environment.

Run the Certis system for faster, lower-risk operations

Schlumberger recommended Cobalt run the 9 5/8-in CERTIS high-integrity reservoir test isolation system that combines the elements of a retrievable packer with those of a hydraulic-set permanent packer, including a built-in floating seal assembly. This feature allows the test string to be run, set, and retrieved in a single run, eliminating unnecessary trips compared with permanent packers. The CERTIS isolation system is set without string rotation or mechanical movement for faster, lower-risk operations, which is especially critical in subsea environments.

Achieved accurate data for reservoir characterization

Cobalt successfully ran, set, and retrieved the test string in a single run, shortening the test duration by 2.6 days. Data from the memory gauges, run below the CERTIS system, were not affected by string movement due to temperature cooling effect and delivered highly accurate data for reservoir characterization.