The NCMA Development Project comprised the development of the North Coast Marine Area, which is located in the Caribbean Sea and Bay of Paria, Trinidad. The project included the installation of a 24" Gas Export Pipeline from the Hibiscus Platform to a landfall at Point Fortin. From the landfall the pipeline was routed by directional drilling and by surface laid pipeline, to a termination point in the Atlantic LNG Terminal at Point Fortin. As part of this project Boskalis was awarded the contract for the provision of landfall, directional drilling and onshore pipeline installation and testing of the 24" gas pipeline system.
Boskalis' scope of work comprised all dredging and backfilling works, all topographic and hydrographic survey activities, the landfall pull-in using linear winches and all onshore pipework including the pig receiver and associated piping at the Atlantic LNG Plant and related supports. The total dredging works consisted of the excavation of a 3,700 m long trench to the -12.0 m LAT contour line. The dredging was carried out by a floating grab dredger, WD Dredgewell, with the assistance of a tug. Material to be dredged consisted of soft to hard clay up to 150 kPa and sandy material. The cut-width varied, depending on the soil characteristics and the layer thickness of the different soil types. The dredged material was sidecasted into a temporary underwater stockpile adjacent to the trench. This material was re-used for backfill after the pipeline installation. The soil at the onshore part of the trench consisted of stiff clay and the excavation of this part of the trench was therefor performed by means of dry plant. A backhoe-type excavator was used to excavate the material and placed it adjacent to the trench into a temporary stockpile.
