Mexico is sweetening the terms of its next oil-block auction in a bid to avoid a repeat of its failed earlier attempt at opening up the industry. The big question now: Is it enough? Investors will answer that question in a sale on Wednesday of shallow-water exploration and production blocks, only the nation’s second since it nationalized its oil industry in 1938. After global energy giants Exxon Mobil Corp., Chevron Corp. and Total SA sat out the first auction in July, Mexico rewrote the rules. This time around, the blocks are bigger, the financial terms less rigid and the government’s slice of the profits smaller. Even with the improved auction terms, Mexico is fighting global headwinds that could hurt the outcome, said Fadel Gheit, an analyst at Oppenheimer & Co. in New York. Oil prices have slumped more than 50 percent in the past year and companies from ConocoPhillips […]