The long-term viability of the U.S. shale boom is uncertain, but the world’s biggest oil companies are making big bets on its success as smaller firms struggle with debt and the lack of scale needed to operate more efficiently. Chevron and Exxon Mobil are emerging as top players in the booming Permian Basin, while European majors such as BP and Royal Dutch Shell are growing in West Texas as well. They have size, economic diversity and the finances to theoretically produce oil and gas with fewer emissions as the world transitions to a lower-carbon future. These companies discussed the importance of growing in American shale oil while pushing for environmental sustainability on Tuesday at the CERAWeek energy conference in Houston. Last week, California-based Chevron and its Texas rival Exxon Mobil made waves when they said they each plan to produce almost 1 million barrels of oil equivalent a day […]