Crude oil prices slid back under $93 a barrel on the New York Mercantile Exchange Thursday as the government reported a weekly gain in U.S. stockpiles. Total supplies reached 381.6 million barrels after eight consecutive weeks of inventory increases, the Energy Information Administration said. With supplies at a 22-year high, the price of crude fell Thursday in New York, with West Texas Intermediate crude oil for June delivery giving up 8 cents to $92.64 per barrel. Natural gas for June delivery added 4.1 cents to hit $2.635 per million British thermal units. Home heating oil was down 0.62 cents to $2.8428 per gallon. Gasoline lost 0.25 cents to reach $2.8757 per gallon. At the pump, the national average price of unleaded gasoline fell Thursday from $3.728 per gallon to $3.722, AAA said.