Abstract

To save substantial expenditure and the loss of production involved in taking a permanently moored Floating Production Storage and Offloading (FPSO) converted tanker to dry-dock, the overlaying of weld metal to the slop tank hull plating, and installation of structural steel in two ballast tanks were completed on location in Indonesia's Natuna Sea area.

This paper discusses the background, outlines the engineering, and shares the experience gained by Marathon Petroleum Indonesia, Ltd. (Marathon) in accomplishing this dry-dock scale workscope on a 20 year old converted oil tanker, now named the "Kakap Natuna". Detailed engineering, thorough planning, and strict adherence to safety procedures, enabled the work to be completed on site without incident on an in-service FPSO, saving an estimated US$ 15 million.

This paper highlights the practicality of attempting such an ambitious project on an FPSO while still producing and shipping oil from two producing fields. The importance of properly scoping and planning a safe job is outlined. The on-site addition of weld metal to the slop tank bottoms was a world first for the certifying authority, ABS. The work was completed on schedule and without any serious accidents or incidents.