Dismantling of the gas production platform “Manslagt Z1“

Contracting entity ExxonMobil Production Deutschland GmbH
Execution time October 2012 to August 2013
General Description of the works:
In the course of the back-filling of the drilling of „Manslagt Z1“, the gas production platform „Manslagt Z1“ situated in the Ems river in front of Emden was dismantled completely, incl. the related pipeline to the mainland. For the preceding back-filling of the existing pipeline to the platform our work vessels provided marine support. The dismantling work included:
  • welding and cutting,
  • dismantling of the pipeline
  • dismantling of the superstructure in one piece using a floating crane and the subsequent dismantling of the foundation structures.
The execution of the described work also included the planning of the dismantling and assistance for obtaining all the required approvals.
Main scope of work:
  • grouting/removing the pipeline in several work steps (length 6 km, depth 1-3 m, 50 mm concrete lining)
  • back-filling/dismantling of the drilling (length 1,000 m, depth approx. 17 m, jacket pipe 20‘‘ grouted)
  • dismantling of the platform (height 18 m, total weight 720 tons)
  • cutting of the foundation piles in a depth of 25 m below ground level by means of water jet cutting
  • removal of the foundation piles
  • dredging work to reconstruct the original tidal flat soil
Special features of the work site:
  • working under tidal influences
  • working in great depth
  • substantial coordination and logistics management
  • implementation of special technologies, such as cutting of the foundation piles underwater from inside
  • use of a 1,800 ton floating crane
  • working at Wadden Sea World Heritage site observing the  „Nulleinleitungskonzept“ (Concept of not Discharging any Pollutant Substances)