Realisation of the shore approach for the installation of an 18” gas pipeline from an offshore extraction platform to an onshore treatment plant.
During the project’s execution, there were two big challenges to overcome, being the presence of very shallow waters and a working gas pipeline, which was positioned only 50 m from the trench.
In this exceptional project Sidra was responsible for the excavation of an incredibly long 4,230 m trench, one of the longest trenches ever realised in the Mediterranean.
The offshore section of the trench was realised by means of two different dredgers, a TSHD and a CSD, while the onshore section was realised by two long reach excavators. The excavation of the trench was carried out in just eight weeks.
With a length of 4,050 m, the pulling cable was installed using a self-propelled pontoon. All of the pull-in equipment was installed by Sidra. This included a 400-tonne winch and the installation of an anchor wall made from sheet piles.
The backfilling was executed using rocks by two self-propelled pontoons equipped with cranes. Additionally, a temporary soil embankment was realised for the loading operations of these two vessels. The gas pipeline was covered with 70,000 tonnes of rock in three weeks.