Offshore U.S. Gulf energy operators have already paid a steep price; more pain could come. Drilling in the Gulf of Mexico is now close to levels seen before the April 2010 Macondo spill that took 11 lives and caused the nation’s worst offshore oil spill. Almost two years after the disaster, companies operating in the Gulf are trying to comply with safety requirements finalized last year, according to the Bureau of Safety and Environmental Enforcement. BSEE’s new safety rules for offshore drillers set standards for casing and cementing…