LONDON—Royal Dutch Shell said it will pursue “at pace” a $7 billion share buyback largely funded from the sale of its U.S. shale business as it faces liquefied natural gas (LNG) outages and slower fuel sales due to the economic hit from Omicron. Shares in Shell, the world’s largest trader of LNG, were down 0.32 percent on Friday after a trading update ahead of its quarterly results on Feb. 3. This compared with a 0.12 percent rise in the broader European energy index. Shell said that its production and liquefaction volumes were impacted in the fourth quarter by unplanned maintenance, mainly in Australia, where its giant Prelude floating LNG vessel was hit by a power outage. LNG liquefaction volumes are expected to be between 7.7 and 8.3 million tonnes, well below a peak of 9.2 million tonnes in the fourth quarter of 2019, Shell said. Shell’s LNG trading results in …