ACG Topsides Design and Fabrication

Abstract The ACG Project concept basis was to deliver as few platforms with as many wellslots as possible, resulting in the delivery of four new drilling topsides facilities having a total weight of the order of 15,500 tonnes each, plus two injection support platforms weighing approximately 13,000 tonnes each. Integrated topsides for this size had never been fabricated in Azerbaijan. The project was also challenged due to limited and out-of-date fabrication infrastructure and no in-country proven fabrication contractor capability for such topsides construction. The solution was to establish a topsides production line approach to delivery, with the design being cloned from deck to deck underpinned by simplistic layouts for drilling and injection support topsides, respectively. Further, the installation of these decks would be via floatover installation method, thereby allowing the maximum amount of onshore commissioning with a minimum of offshore commissioning. All topsides fabrication would occur at two in-country fabrication yards, with the exception of the drilling facilities and the living quarters. This paper describes the development of the topsides layouts, supporting engineering design, fabrication yard upgrades, cloning benefits and decisions associated with where and how fabrication could optimally be achieved. The ACG topsides production line was successfully established and six topsides have been delivered offshore since start of fabrication in November 2001. As a result, similar production lines are being established on other developments. The information in the paper will be of use to others who have similar large field offshore developments where full cycle delivery - from start of engineering design to start of production - can be optimised. The production line approach, underpinned by standardisation of design, fabrication processes and people, proved capable of delivering deck-on-deck reductions in cost and schedule. The delivery can be improved further through the rigorous use of lessons learned feedback. This project demonstrates the benefits of developing innovative solutions to overcome specific problems. These solutions were relevant in a part of the world that has not traditionally delivered facilities to shareholder standards. Introduction The ACG Full Field Development (FFD) Project began in 1997, but, due to a variety of economic and geopolitical reasons, the first phase of project sanction did not occur until September 2001. The chosen offshore development strategy involved three phases of incremental development - two large fixed offshore platforms for each phase (see Figure 1 at end of paper).