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Sayı: 51 - Nisan 2017


Azerbaijan Baku SHAH Deniz 2 Offshore Platform

TANAP Project, with construction ongoing in a fast track whose significant portion passing through Turkey and carrying Azerbaijani natural gas to Europe

TANAP Project, with construction ongoing in a fast track whose significant portion passing through Turkey and carrying Azerbaijani natural gas to Europe, forms the South Natural Gas Corridor by joining South Caucasian Pipeline (SCP) and Trans-Adriatic Pipeline (TAP) and two main outlet points in Eskişehir and Thrace within the boundaries of Turkey for con­nection to national gas distribution grid With this project, a significant portion of the natural gas to be extracted from the Caspian Sea will be delivered to Europe through Turkey. Natural gas reserve 
being the start point of the project is in Shah Deniz field in the Caspian Sea having a water depth varying from 50 to 500 meters located approx­imately 100 km south of Baku. Nat­ural gas is drilled from these reserves through offshore platform structures and delivered to its first stop, the onshore terminal.   Offshore platforms are very complex structures from manufacturing to erection. Platform is comprised of two main sections, “top-side” and “jacket”. Jacket supports the top platform called “top-side”. “Top-side” comprises of more than one floor depend­ing on operational requirements. Most significant characteristic of “top-sides” is that they have an extremely congested layout including many technological equip­ment, piping, living and service quarters in a very limited space. Platforms are erected through an extremely precise operation which can be called flotation-submergence method. 
Supporting structure of the platform is steel construction. In comparison with normal steel structures, platforms are subject to very strict design criteria due to usage and operational characteristics. In this article, “top-side” manufacturing en­gineering studies of two offshore structures manufactured simultaneously for Shah Deniz Bravo (SDB) complex. SDB Platform Complex comprises of Production and Ascender platform (SDB­PR), Living Quarters and Services platform (SDB-QU). Two platforms are connected to each other through a steel construction bridge.  (Figure 2). Weight of SDB-PR plat­form is approximately 16500 tonnes and comprised of units where fluids produced from wells are collected, processed and im­ported to onshore terminal through gas and liquid pipelines while SDB-QU platform having an approximate weight of 13000 tonnes contains living and service units as is evident from its name.  
Manufacturing and onshore erection works were executed in the yard located in Ba­ku-Bayil district. Due to the characteristic of the structures, steel supporting structure, mechanical installations and other units are installed through a specific sequence.  
All onshore erection works are performed on a dry dock called “skid way” to slide the platform to sea after completion of the structure.
In this respect, 60 personnel were employed in Shah Deniz Bravo Platform Complex project. In such a project requiring tech­nologically challenging operation, it is of significant importance to utilize comput­er-aided 3D design modelling with the aim of reaching interdisciplinary integration and engineering perfection. In this regard, Tekfen Mühendislik provided a total of 192 hours of structural steel and Tekla Structure training (48 hours of initial training and 144 hours of application training) to local resources in Baku, Azerbaijan (Figure 3). The important point to be emphasized in these trainings is the fact that majority of the local resources were not familiar with structural steel works. On the other hand, more than half of the subject personnel were equipped with a level of knowledge and experience which may be more efficient in following projects upon te completion of this project. In this respect, the project created significant added value in general in Azerbaijan for creating qualified workforce. Priority was to set a standard in terms of engineering through trainings conducted before preparation of offshore manufac­turing drawings. In this regard, standards are set for categories such as harmony in representation of cross-sections, details and item numbers in members, text fonts, con­tent, scale etc. Furthermore, a strict control procedure was established before sending steel drawings to manufacturing since tol­erances are very limited and re-work costs are significantly high in terms of material, workmanship and work schedule. For this reason, preliminary design drawings and detail drawings for the subject connection were definitely comparatively checked. If any difference is observed in information such as dimension, welding, material type and thickness during the checks, employer is advised accordingly. Therefore, area of responsibility is expanded in the project, and both time is saved and employer trust is established with flawless design. Structural steel used in Shah Deniz Bravo Platform Complex is high strength steel with S355 and S460 grade, and almost all are designed in welded connections. Bolted connections are used only in detachable modules comprised of stairs and guard rails. Although there is no significant difference in terms of design and manufacturing between Shah Deniz-2 and Shah Deniz-1 (Chirag) offshore platform projects, Shah Deniz-2 project was completed approx­imately one year earlier when compared with the previous project. Setting up an office of Tekfen Mühendislik adjacent to construction site to work parallel with manufacturing and providing instant feed­back during the manufacturing phase have significant impact on shortening the project period. Another factor shortening the man­ufacturing period is minimizing the rate of error in detail design through the use of 3D modelling in offshore design and training of personnel. Another significant outcome of the project is the supply of qualified manpower in Azerbaijan and created added value through keeping limited resources from company resources and training of local personnel. 
Çelik Yapılar - Sayı: 51 - Nisan 2017

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