Discovered in 1997, sanctioned in 2003 and brought on stream in 2006, the Dalia field is located in Angola's legendary offshore Block 17. Total has a 40% ownership interest in it and also operates Girassol, Jasmim, Rosa, Pazflor and CLOV there, producing 700,000 barrels a day.
The Dalia field development comprises a total of 71 wells, plus 11 more for the Dalia Phase 1A and Dalia Phase 2A infill projects to maximize the recovery of reserves. As part of the infill phases, two producer wells were plugged and abandoned to recover their slots on the existing subsea manifolds. Total's teams in Angola hit on a way to cut costs and speed up first oil: reusing the two Xmas trees left on the seabed.
A Fit-for-Purpose Approach, But a World First in the Deep Offshore
In 2016, both a wellhead inspection program using remote-operated vehicles and a risk assessment confirmed the feasibility of this fit-for-purpose approach.
- One Xmas tree was reused without bringing it back up to the surface, a global first in the oil and gas industry. The wellhead was transferred directly to its new location, 25 meters away.
- The second Xmas tree was brought back up to the surface, inspected and refurbished to repair certain critical components. By making it possible to order replacement parts ahead of time, the fast-track subsea inspection and repair program was shorter and cheaper than its predecessors.
An Efficient, Cost-Effective, Pioneering Project
The two infill wells were delivered eight and ten months ahead of schedule respectively. That means a $500,000 capital expenditure yielded a total of 5 million barrels once the wells began operating. This enabled Total E&P Angola to fast-track the project's first oil and slash costs.
The solution demonstrates our ability to design and implement innovative projects, confirming once again our deep offshore expertise. Equipment reuse in strict compliance with our safety standards and operational requirements will be widely replicated on future brownfield developments. Examples include Nigeria, where reusing a Xmas tree in the Akpo field will shorten project time, and Angola, where we're looking at the feasibility of reusing other types of equipment.
Team that participated in the Xmas tree reuse project in Angola
Fast-track refurbishment flow chart
Subsea inspection (DAL-724)
Xmas tree recycling process
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