The United States boasts the world’s largest stash of emergency oil supplies, yet the country’s ability to influence global crude markets with releases from that reserve has waned. The Obama administration hopes to fix that problem with an overhaul of the Strategic Petroleum Reserve, or SPR, and details about its plans should be revealed in coming weeks. The Energy Department is expected to send Congress a report detailing a proposal to modernize the SPR, a string of crude-filled underground salt caverns guarded by sharpshooters in four remote locations on the coasts of Texas and Louisiana. The system holds 695 million barrels, or what the entire country uses in about five weeks. The North American oil boom, in which U.S. crude output has risen to more than 9.4 million barrels […]