South Stream Transport B.V. is building the TurkStream pipeline system to export gas across the Black Sea from the Russian coast at Anapa to a landfall at Kiyiköy, Turkey. TurkStream comprises: two pipelines for 31.5 BCM/yr, 32-inch outer diameter, 940 km each, 2200m maximum water depth, 50-year design life, 300 bar design pressure. Construction on the TurkStream pipeline system started in 2017, and first gas is planned by the end of 2019.
The challenge
TurkStream is one of the most challenging pipeline projects ever attempted both in terms of design and manufacturing & construction. Challenges to be overcome have included:
- Frontier area
- Subsea environment with high H2S values
- Challenging seabed conditions with geohazard risks
- Extreme water depths
- Linepipes manufactured with “fabrication factor” (Alpha fab) of 1.0 as per DNV OS-F101
Already during the initial feasibility studies, INTECSEA identified the need to extend the notional ‘technology boundary’ for deepwater gas pipeline systems. Significant technology advances were required to achieve a pipeline design that could be manufactured and installed safely and efficiently. INTECSEA defined and managed testing and qualification programs to achieve these advances.
Our approach
INTECSEA has had the unique opportunity to have contributed to all phases of the TurkStream project. Our scope of work has included:
- Feasibility study
- Line pipe materials testing program management
- Survey Supervision (Onshore & Offshore)
- FEED (Onshore stations and offshore pipeline)
- Line pipe manufacturing qualification
- Permitting Support
- Detailed design (as sub-contractor to Allseas BV)
- PMC Support for Execution
- Owner’s Engineering during offshore construction phase
- Construction supervision for both onshore and offshore activities
- Owner’s Engineering to develop integrity management and operations documentation To a large extent, INTECSEA has worked as part of an integrated team with South Stream Transport BV
Results
INTECSEA’s technical expertise and engineering input has been an enabler for the TurkStream project. We successfully extended the notional technology limits for ultra-deepwater gas pipelines to achieve a pipe design that could be manufactured by multiple line pipe mill supply chains and installed using the available installation assets. Furthermore, we have provided technical, procurement, construction and project management support to South Stream Transport BV throughout the project timeline. As of January 2019, both pipelines have been installed successfully, and the project is on schedule to meet its first gas target date.
