In one aspect, a method and apparatus for intervening in an offshore pipeline while diverting fluid flow to a storage site is provided, so that production through the offshore pipeline may continue while conducting a pipeline intervention operation. An offshore vessel may be used to divert and store fluid flow while intervening in the pipeline. In another aspect, a method and apparatus for drilling a subsea wellbore with an offshore vessel is provided. The method and apparatus involve drilling the wellbore and casing the wellbore with continuous casing lowered from the offshore vessel.