LONDON—Oil prices climbed on Tuesday as Shanghai’s relaxation of some COVID-19 restrictions eased concerns about Chinese demand and as OPEC warned it would be impossible to replace potential supply losses from Russia. Brent crude futures rose by $3.26, or 3.31 percent, to $101.74 a barrel at 1002 GMT while U.S. West Texas Intermediate was up $3.01, or 3.19 percent, at $97.30. Both contracts lost about 4 percent on Monday. The Organization of the Petroleum Exporting Countries (OPEC), meanwhile, warned that it would be impossible to replace 7 million barrels per day (bpd) of Russian oil and other liquids exports lost in the event of sanctions or voluntary actions. The European Union has yet to agree any embargo on Russian oil, but some foreign ministers said the option is on the table. “The oil market is still vulnerable to a major shock if Russian energy is sanctioned, and that risk remains …