Oil prices fell closer to $91 a barrel on Thursday, sagging for a fourth straight day as high U.S. inventories and weak economic data from Europe, China and Japan reinforced fears of a deeper global downturn.

By early afternoon in Europe, benchmark oil for October delivery was down 45 cents to $91.53 per barrel in electronic trading on the New York Mercantile Exchange. The contract finished at $91.98 on Wednesday, dropping $3.31, or 3.5 percent.