I say the Iran-India Pipeline, should go the sea route.
Well it would incredibly expensive......
World's deepest underwater pipeline challenges industry.
It is a proposed project almost beyond description and imagination: an underwater long-distance gas pipeline from Oman to India that requires a large part of the approximately 1,135-1,200 kilometer (705-750 mile) line to be laid in the Arabian Sea at depths as low as 3,500 meters (11,500 feet).
The route will include two identical 24-inch internal diameter pipelines, each capable of delivering 1 Bcf/d of natural gas from the Central Oman Gas Fields to the inshore custody transfer point in Bhachau, India. Some 800,000 tons of pipe will be needed for the project and just under half of it will have to be laid at the 3,500-meter depth, forcing it to withstand enormous water pressures. The required pipes are 12 meters (nearly 40 feet) long; have an outside diameter of 711 millimeters (28 inches), and walls 41 mm (1.615 inches) thick or 44 mm in case the pipes are to be laid in 500-km (310.7 miles) of ultra-deep water. Wall thickness twice that of normal offshore welded pipes is required.
Europipe GmbH manufactured the first 1,000 feet of a new generation of large-diameter pipe with 41-millimeter walls. With the deepest gas pipeline in existence today lying at a depth of approximately 800 meters (2,625 feet) and needing virtually no special considerations for external pressure, there is nothing to compare it with.
Not only are the pipes required to have thick walls yet relatively small diameters, but they must also have ideal roundness to prevent their premature deformation from the extreme outside pressure. Even minor deviations from perfect roundness can result in premature collapse of the line due to buckling.
To date, no large-diameter line pipes have ever been manufactured with such an extremely low diameter-to-wall thickness, let alone pipes made from high-strength X 70 grade steel. The absolute production record to date was a wall thickness of 40 millimeters, and even that could only be achieved at considerably larger diameters.
Extensive Testing
Europipe engineers went into action, first by painstakingly inspecting all machine-tools and plants, then the Mannesmann Research Institute in Duisburg-Huckingen was commissioned to carry out a computer simulation program. In the end, the results confirmed in principle that it is possible to manufacture high-strength steel pipes with such extreme dimensions.
Furthermore, researchers subjected the test pipes to extreme outside pressures and carried out so-called collapse tests which prove that they are resistant to buckling. For the test, the pipe is closed off at both ends, placed in a container and exposed to external pressures rising up to 500 bar until buckling occurs and the pipe collapses.
A further test series proved that if the pipes would fail, the fracture appearance would be ductile and not brittle. For these tests, artificial notches are cut into the pipe wall before subjecting the pipe to internal pressure to bursting point. The resulting fracture surface is then assessed as to whether the fracture is brittle or ductile. As the surface formation of the fracture depends on temperature, such tests must be carried out at well below the lowest temperature the pipes will be exposed to, i.e., at around 0 [degree] C, and the pipes must be cooled accordingly.
Europipe Awarded Option For More Pipe
After all of the studies concluded, Europipe eventually produced the first 1,000 meters of pipe for the Oman Oil Co. and these are now being used in welding tests by different pipe-laying companies. Europipe has already been awarded an option for the production of another batch of 7,000 meters (23,000 feet) of pipe.
With an inside diameter of 610 millimeters (24 inches) and otherwise unchanged parameters, these will be used in undersea laying tests.
The construction of the first pipeline has been tentatively scheduled for completion on June 30, 1999, and the second pipeline is expected to be mechanically complete in 2001. There have been some questions regarding financing raised, however.
All of the specifications and demands made on pipe manufacturers, pipeline constructors and operators present a major opportunity to be involved in the start of schemes to transport gas under the ocean at such depths. In view of the demands for fossil fuels for energy production and supply, such schemes will be unavoidable in the long run.
