Dismantling of an oil rig, Bay of Kiel
The Schwedeneck-See oil field is located in Kiel Bay at a depth of 1,500 meters. From 1984 to 2000, oil was extracted here using two production platforms and transported via pipelines to refineries near the coast. After 16 years of operation, the proportion of water in the production increased, which led to the cessation of operations. Subsequently, the platforms and their bases were to be dismantled in an environmentally friendly manner.
For the dismantling of the Alpha platform, it was necessary to prevent water from entering the concrete base. To do this, the existing pipelines in the floating structure of the drilling rig had to be retrofitted with seals. The specific challenges and measures implemented were:
- Sealing the pipes: Steel covers were welded onto the ends of the pipes to create a base for sealing.
- Injection with WEBAC 151: The cavities/voids were then filled with the moisture-reactive PU injection foam resin WEBAC 151. The drill holes were located approximately 16 meters below the platform. A total of 60 meters of high-pressure hose and an injection pump with the appropriate delivery rate were required for the injection. Approximately 50 kg of WEBAC 151 was used per drill hole.
- Challenging conditions: The work was made difficult by the long grouting distance, relatively low temperatures (10–12°C water temperature with approx. 3°C air temperature), high humidity (drizzle), and wind speeds of 5–7.
The injection work on the Alpha platform took four days and was completed successfully. A total of almost 700 kg of WEBAC 151 was injected, 16,000 tons of reinforced concrete were recovered from the sea and, after injection, dismantled in an environmentally friendly manner and prepared for recycling.
