Natural gas transport oversea - by multiple thick walled steel pipes in shelf and steel armoured rubber pipe at depth

摘要

Natural gas is transported from offshore wells of great depth to the coast or from the coast of one country to another by a composite system of pipelines. From the land station across the continental shelf, several thick-walled steel pipes of small diameter are laid in parallel. Where the shelf dips to greater sea depths, these are combined through a manifold to a single large-dia. pipe. The latter is made of steel cord armoured rubber. A compressor keeps the whole system at a pressure above the hydrostatic pressure of the deepest pipeline point. The favourable ratio of wt. per unit length to buoyancy of the small steel pipes facilitates their laying. The rubber pipe is elastic enough to withstand flattening, when empty, without damage. The flexibility of the rubber pipe also facilitates its laying. This system is more economical than transport in liquefied natural gas tankers.