Managing the Salvage, Removal, Preservation and Re-Installation of Tilted Wellhead Platform

This paper describes the planning, offshore execution and technology involved in the intact salvage, removal, preservation and relocation of a Wellhead Drilling Platform (WHP) which was tilted during drilling operation in the "X" field. The field development plan consists of a WHP tied-back to a Floating, Production, Storage & Offloading (FPSO), anchored at 700 m away from the WHP. The oil field is located 110 km from shore and at water depth of 57 m. The Project Management Team (PMT) had completed the installation of the WHP, unfortunately mishap was happened when the WHP experienced tilting during drilling operation. The platform tilted/leaned two (2) degrees towards the drilling rig. The strategy adopted by the PMT was to rig-down and move out the affected rig; immediately salvage the newly installed 1,300MT WHP's topside. The work was executed under the crisis management envelop with the aim to save the rig and platform from total loss i.e., to avoid the platform topples into the sea and subsequently hits the rig. The salvage operation employed unique processes, procedures, and technology to safe hold the tilted platform by Anchor Handling Tugs (AHTs) and pipelay barge; rig-down and move out the drilling rig, reinstatement of lifting lug/pad eyes which had previously removed after completion of topside installation and finally removal of topside from the tilted jacket. The topside then transported to the fabrication yard, where there the topside had been preserved on the transportation barge for a period of five (5) months while waiting for the new jacket to be fabricated and installed. The re-development of the affected offshore facilities from the incident involved installation of new jacket at 150 m away from the tilted jacket location, re-installation of the topside to the new installed four (4) legged jacket, re-routing the previous installed infield pipelines (8" Liquid, 16" Wet Gas and 12’ Export Gas pipeline from FPSO) and tied-in to the new platform. The planning, innovation and execution has resulted in a significant cost containment and managed to avoid major disaster; subsequently safeguard Company's reputation. The salvage of the topside and rejuvenation of the pipelines have managed to avoid the reconstruction of the topside module which potentially could lead to non-cost recovery of huge amount of additional cost (in USD millions) and managed to avoid any Loss of Primary Containment (LOPC) by taken all the necessary precautions.