LONDON - Oil supplies are set to tighten further in coming weeks even if the U.S. and Iran agree on a peace deal to end their war because it will take weeks for oil shipments to resume from the Middle East Gulf and reach refiners worldwide — so oil companies will continue to deplete storage tanks to meet peak summer demand.The world has used temporary buffers — commercial stockpiles, oil in transit or held in storage at sea and emergency reserves — to offset the shock from the war in the Middle East. The full impact of the disruption to oil supplies has yet to wash through markets and the global economy because it will be many ​months before Middle East production and exports return to prewar levels, said executives from major energy companies, investment banks and market analysts.The rapid depletion of commercial stockpiles and emergency reserves has come at a time when ‌stockpiles typically ‌build as refiners and retailers prepare for peak demand during the Northern Hemisphere summer. The global energy system will soon enter peak demand in a weakened position to deal with ​the spike in consumption from summer driving, aviation, farming and freight.