Large Diameter Drilling (LDD) and Barge Master have combined their expertise to complete what is said to be a world first drilling operations from a diving support and construction vessel (DSCV) in water depths in excess of 270 meters.
By integrating LDD’s reverse circulation LD2500 drill rig with Barge Master’s motion compensation platform (BM-T700) LDD have completed the installation of seven anchor mooring piles for a catenary anchor leg mooring (CALM) buoy – with the technique employed, whilst unique and bespoke, having the potential for industry wide application.
The Project (Limetree Bay Installation) was executed in the Caribbean Sea, some 2 kilometers off the coast of St. Croix, USVI, for Imodco Terminals, a subsidiary of SBM Offshore.
The Project was challenging; operational and environmental constraints limited the use of more conventional methods.
The LDD devised solution mounted the LD2500 to a cantilever beam which was subsequently affixed to the Barge Master T700 motion compensation platform.
Typically, reverse circulation drilling takes place off a jack-up barge (JUB) or from the pile top itself, however substantial water depths (ranging between 80-275m), challenging sea-bed conditions (sea-bed slopes up to 17 degrees) as well as the physical attributes of the anchor pile design made this impossible, LDD explains.
The equipment spread was mobilised on-board DSCV SBM Installer during Q1 2019 in Rotterdam, after which she sailed to St. Croix, USVI.