The U.S. shale patch will not help ease what could be a very tight global oil market when the EU embargo on imports of Russian seaborne oil enters into force in just a few weeks. Even if they wanted to, American producers would not be able to boost oil production too much, despite repeated calls and threats from the Biden Administration, which is seeking relief for consumers at the pump. Inflation, labor shortages, and supply-chain delays in the short term and a lack of certainty over the U.S. energy policy in the medium term are constraining…