A Picture Of Pipeline Construction Oman.

A tie-in on the Sur 48″ diameter gas pipeline, 1998.

48" diameter pipeline.

The picture above I took with a pre-digital Canon Ixus. I found it handy, around the size of a cigarette pack, slipped into the top pocket of my overalls no probs. I was so impressed with it I bought a Canon digital Ixus 6 a 6 mega pixel mini camera which I use constantly, for such a small camera it works marvels. Anyway back to the topic of this post, the tie-in. In pipeline construction the pipes are strung out along the trench and are welded up by what we call the front end welding crews. At road crossings and difficult areas they leave gaps for the tie-in crews to weld at a later time.

This tie-in is on the ‘Saih Rawl to Sur OLNG’ pipeline, Oman. I enjoyed this pipeline, it was big, noisy, hot and long at 352Km. The main contractors were a joint venture, Saipem an Italian company and CCC a Palestinian company. Over the years I’ve worked with this partnership 3 times, they always seem to get the bigger jobs. The mountains in the background are a range that you pass through on the way to ‘Sur’ on the coast a small town but growing fast.

Some figures.

Pipes like the ones in the picture are 48″ diameter and average 13meters in length, the approx. weight of the heavy wall pipe 23mm which is used in road crossings etc. is around 10 tonnes. If I remember rightly we welded together around 26000 pipes which weighed in at around 186000 tonnes. All figures are from memory and approximate.

The front end welding process was semi automatic PWT and PASO, PASO is Saipem’s own technology, PWT (Pipe Weld Technology) is a very similar process. The pipes to be welded are held together using an internal pneumatic clamp which has copper backing shoes, the actual welding is done by welding bugs controlled remotely by the welders, these welding bugs travel around the outside dia. of the pipe on an aluminium ring.

tie-in 48" diameter Sur to Saih Rawl, Oman

Another picture of the same tie-in pictured above after the welding has been completed.

The welding of tie-ins is usually done manually using at least two qualified welders and for these big pipes can take 4 or 5 hours. When the welding is complete the weld is cleaned up for inspection. The weld after being accepted is given a unique number. This enables the QA dept. to identify the weld for any repairs found after it has been x-rayed. Once the weld is cleared it can be coated using a specially designed plastic heat shrink sleeve.

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