Helped by higher crude and product trading profits and increased refining margins, Shell (NYSE: SHEL) smashed earnings estimates for the first quarter of the year and announced a new $3.5-billion share buyback as the UK-based supermajor looks to close the stock valuation gap to its U.S. peers. Shell reported on Thursday adjusted earnings of $7.7 billion for the first quarter, down from $9.6 billion for the same period of 2023. This year’s first-quarter earnings were higher by 6% compared to the fourth quarter of 2023, thanks to…