Innovative Subsea Visual Positioning Technology for Offshore Structure Installation

Abstract Two Offshore Wellhead Facilities (OWF) known as Platform A and Platform B were engineered, fabricated, and installed, at more than 40m water depth with bridge link to the existing platforms at South China Sea. The structures were designed by adopting a "Lego" building block concept for its simplicity in fabrication, transportation, and offshore installation. Despite its simplicity in structural engineering, each structure comprises of surface and subsea structures of which need to be fitted and integrated perfectly to form a single platform. Therefore, precise survey, positioning and monitoring system were critical during the offshore installation phase so that all components (i.e., caisson pile, subsea template, guide sleeve, top sleeve and topside) were fitted and installed within the required tolerances to ensure engineering and structural integrity.