U.S. oil and gas major Exxon Mobil (NYSE: XOM) has announced on Wednesday that it has made two more discoveries at the Sailfin-1 and Yarrow-1 wells in the Stabroek block offshore Guyana, bringing discoveries on the block to more than 30 since 2015. Exxon revealed that the Sailfin-1 well was drilled in 4,616 feet of water and encountered 312 feet of hydrocarbon-bearing sandstone, while the Yarrow-1 well was drilled in 3,560 feet of water and encountered 75 feet of hydrocarbon-bearing sandstone. Exxon did not disclose how much crude oil or gas it…