Tough market conditions have seen the price of oil drop which with the subsequent uncertainty surrounding the industry have seen the oil and gas industry concentrate on reducing the cost of designing, installing and operating pipelines. A critical process for the industry is the procurement, manufacture and installation of appropriate linepipe. The method of installation is often dictated by the pipe size and the water depth that the pipe is to be laid in, however there are times when the choice of lay method is due to vessel availability and relative costs for each technique.
In early 2014, Tata Steel successfully manufactured and delivered 16"OD × 0.875”WT X65 submerged arc welded longitudinal (SAWL) linepipe for installation via the reel lay method. Notable features about this fact were the size, which represents the thickest 16” external diameter UOE pipe yet delivered by Tata Steel, and that this was to be the first UOE pipe to be installed by the reel lay method in the North Sea. The ability to manufacture small diameter thickwall linepipe was only possible due to recent operational developments including an established tooling programme and a fully validated Finite Element (FE) model of the UOE process, along with years of experience of integrating these tools into the manufacturing process.
This paper discusses the manufacturing challenges for small diameter thickwall linepipe, and how with the aid of modelling tools, innovative thinking and previous experience in supplying small diameter thickwall linepipe into two reel-installed projects, the pipe was manufactured and delivered with the properties shown to be compliant with DNV OS-F101 Supplementary Requirement P.
