Ocean BlackHawk drillship; Source: Diamond Offshore

One Diamond Offshore drillship done with its job while another continues work off Africa

Offshore drilling contractor Diamond Offshore Drilling has confirmed that one of its drillships wrapped up its drilling assignment last week at Senegal’s first offshore oil development. As the drilling campaign is not over, another drillship will take care of the rest of the drilling work on this project.

Ocean BlackHawk drillship; Source: Diamond Offshore

The 23-well drilling campaign for the first phase of the Woodside-operated Sangomar field development started in July 2021 and the first development well was drilled and completed, including the installation of the xmas tree, in September 2021.

This was carried out using the Diamond Offshore-owned drillship, Ocean BlackRhino. The drillship was expected to be joined by another Diamond-owned rig, Ocean BlackHawk, in mid-2022. The contracts for both of these drillships were inked back in April 2019.

According to Diamond Offshore, last week marked the end of the Ocean BlackHawk drillship’s drilling campaign in Senegal for Woodside Energy. The rig, which started operations in the Sangomar field a year ago, has since delivered “outstanding performance” for the project, says the rig owner.

The rig ended the entire campaign with 2.39 per cent non-productive time (NPT) and drilled 11 top holes and 17 intermediate holes as part of a batch drill campaign, for a total depth of 35,500 meters (119,757 feet).

“The team realised significant improvements in the performance from batch one to five achieving efficiency gains of more than 30 per cent. These results could not have been realised without the strong partnership and team culture on the rig,” underlined the company.
The remaining drilling activity will be completed by the Ocean BlackRhino drillship. The first oil is now targeted for mid-2024. The Sangomar field development Phase 1, targeting approximately 230 million barrels of crude oil, will be Senegal’s first offshore oil project after it comes on stream.

It will consist of a stand-alone FPSO, named Leopold Sédar Senghor, with a production capacity of approximately 100,000 barrels per day, 23 subsea wells, and supporting subsea infrastructure. Woodside is the operator with an 82 per cent participating interest in the project, while its parent, Petrosen, holds the remaining 18 per cent.

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The 2014-built Ocean BlackHawk and Ocean BlackRhino are identical ultra-deepwater drillships from Hyundai Heavy Industries, which come with dynamic-positioning, dual-activity capability, maximum hook-load capacity of 1,250 tons, two seven-ram blowout preventers, water depth capabilities up to 12,000 feet, and drilling depth capabilities up to 40,000 feet.