Pipelines

48″ Gas Pipeline – Trench Excavation, Oman

 Saih Nihayda To Al Kamil Gas Transmission Pipeline 2005.

          A Big Pipeline Requires Big Machines

  If you are constructing a 48″ diameter gas transmission pipeline you need to consider the trench excavation and the high specifications required by the oil and gas companies. It’s not just, “dig a trench and bury the pipeline”  the trench has to meet strict requirements as to depth and cover. The pipeline must not be lowered on to rocks etc. The newly welded pipes are treat like babies and have to be put to bed on a layer of  sand which is previously screened and all rocks removed. This sand must be at least 150mm deep and in some cases 300mm all around the circumference of the pipe. If the contractor does not own or has not made provision for hiring sand screening plant, then the sand has to be hauled from suppliers many Km away at great cost.

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48″ Gas Pipeline Internal Clamp.

               Routine Maintenance On The Internal Clamp

The internal clamp used in the front end welding operations is inspected regularly and any adjustments required are made at this time. Generally all that’s required is a clean up using compressed air to get rid of the welding dust. The copper backing shoes are then inspected and replaced where necessary.

This picture shows the internal copper backing shoes used in the PASO welding process. The aluminium band on the outside of the pipe is the track to which the external welding bugs are attached. The clamp has a long handle which is inserted into the next pipe to be welded and is controlled by compressed air. Once the welding is complete, the handle which protrudes from the the open end is used to release the clamp and to activate the pneumatic motor which sends it up to the next joint to be welded.

   SideWallFusion

Recommended reference books on pipeline construction at amazon.com

Welding:
Pipe Welding Procedures
The Pipe Fitter’s and Pipe Welder’s Handbook, Revised Edition
Pipefitters Handbook
Pipe Fitter’s Math Guide
Audel Pipefitter’s and Welder’s Pocket Manual
Audel Welding Pocket Reference (Audel Technical Trades Series)
Oil & Gas Pipelines in Nontechnical Language
Pipeline Rules of Thumb Handbook, 7th Edition

Pipeline Corrosion Control:
Pipeline Corrosion and Cathodic Protection, Third Edition

Excavations:
Excavation & Grading Handbook
Estimating Excavation
Excavation Systems Planning, Design, and Safety

Pipeline Construction Accidents Do Happen.

Some Pictures From Various Pipeline Construction Projects.

No-one wants to see an accident happen but they sometimes do. During the course of constructing a major pipeline, accidents and mishaps occur. Here’s a couple of pics showing what can happen.

 During the night a bedouin driver ignored warning signs in both English and Arabic, drove around the barriers and piles of spoil blocking the road to drive into the open trench and on to the pipe. I was driving down the pipeline right of way to work and came across this sight.

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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.

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