Challenging Developments
Gas and condensate field developments in the GoM are too numerous to list in a short article. However,it should be noted that deepwater technology is constantly stretching the boundaries with developments being reported in increasing water depths. The Mensa field developed by Shell in 1,600m of water is quite an innovative development with subsea wells tied back to a 100km distant shallow water platform, West Delta 143. Several deepwater gas field developments employ a tie-back strategy to existing infrastructure. Some of the upcoming deepwater gas develop- ments that present major challenges are noted in this article.
The Greater Sunrise gas/condensate field, located in Timor Sea 480km north-west of Darwin, Australia, has been considered for development using a world- first floating LNG plant. The field is reported to have nine trillion cubic feet (tcf) of reserves. Remote location from markets and land made it an ideal candidate for development using the latest novel technology. Ormen Lange in 800–1,200m of water lies 140km west of Kristiansand. Several options have been considered including a spar tied to the seabed or a concrete platform with pipeline export to shore for processing. The favourite scheme appears to be a subsea template with export to shore. Further north, in the Barents Sea, the Shtokman field lies 560km north of Murmansk. A field development study is being conducted to determine a phased development similar to Ormen Lange (subsea templates with export pipelines). The field is one of biggest in the world with reported reserves of 113tcf of gas.
Figure 1: Scarab/Saffron Development in 650m Water Depth –
Offshore Egypt (BG Group)
The Scarab Saffron gas fields form part of the West Delta Deep development located in 650m water depth and 90km off the coast of Egypt. The fields have been developed using subsea manifolds with wells tied in and export lines to shore. This development came on-stream during 2003.
The flavour of development for most of the fields located in hostile and remote environments is to exploit subsea technology with direct export pipelines. Consideration has to be given to the terrain that the pipeline route has to take, as significant changes in topography of the seabed can make development very complicated. The challenges in deepwater and remote locations are immense. The future lies in floating LNG plants. Once all the safety issues have been resolved, ‘stranded’ gas fields will be developed using this technology.
Conclusion
The search for low-cost gas reserves will gain more momentum with high oil prices and the world’s increased focus on the greenhouse effect and its impact on global warming. Frontier areas will be explored with increased zeal and new gas discoveries will be exploited with innovative technology. As safety issues are resolved, stranded gas fields in deepwater will be developed using floating LNG plants.
Category:
Overview & Strategy
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