The chemicals giant owned by billionaire Jim Ratcliffe has roiled global energy markets after shutting the North Sea’s most important oil and gas pipeline system after discovering a widening crack. Ineos, which owns the Grangemouth refinery, said it discovered a small crack in the pipeline outside Aberdeen just weeks after buying the pipeline system from BP. The crack has grown to almost six inches long despite efforts to limit the damage. The shock shutdown propelled the global oil price to two year highs of over $64 a barrel over fears of a potentially major supply disruption for Britain’s remaining refineries.