Ramboll was deeply involved in the development of the Upper Zakum oil field off the coast of Abu Dhabi. The Zakum field stretches over some 1,200 square kilometres - making it one of the largest oil fields in the world with a very long expected operating life.
The oil field operator, Zakum Development Company (ZADCO), has permission to increase the production rate by 40%. As an alternative to establishing numerous platforms in order to increase oil production, this development project comprised the evaluation of the construction of 4-6 new artificial islands to be used as the centre for drilling and oil production in future.
Study of effects on existing facilities and environment
In 2009, Ramboll was appointed as consultant to study the effects of introducing the artificial islands and burrow areas in the existing oil field on the existing jackets, pipelines, cables and environment, wave- and current conditions, and how the changes in hydrodynamic loads impact the structural integrity of the existing platforms. Following a successful cooperation with the operator during the first phase of work, Ramboll was also appointed consulting engineer for the second phase of the project.
During Phase II, the scope was to establish the changes in the met oceanic conditions, including changes in the morphology, at the oil field as a result of establishing the six artificial islands. Based on these studies, the effects on the environment as well as on existing structures and pipelines were evaluated. This enabled the client to assess the feasibility of constructing the artificial islands in terms of implications on existing infrastructure.
Ramboll's analysis showed that the construction of the artificial islands would not affect the environment and the existing structures significantly. However, some pipelines in the vicinity of the islands were found to require additional stabilisation in terms of concrete mattresses.
Detailed project information
The in-place analysis of the platforms was carried out using SACS and the push-over analysis was performed by using USFOS. Riser in-place analysis was performed for several risers on highly utilised platforms using ROSA. In order to establish the on-bottom stability of pipelines, free spans and crossings were evaluated at critical locations. The effects on environment and water intake from settling and suspended sediments due to dredging and island construction operations were also evaluated. In addition, a detailed structural analysis of eight selected platforms with risers which would experience a significant increase in hydrodynamic loads and a study of the on-bottom stability were included.
Thumbs up for artificial islands
In collaboration with ZADCO shareholder ExxonMobil, Zadco evaluated the concept of artificial island based drilling and production centers and found it to be an attractive forward development plan, which was pursued and executed.