Low inventories helped push crude oil to $32 a barrel Monday, but the near-month contract for West Texas intermediate didn't stay there. The September contract settled at $31.94, up 3% from Friday's session on the New York Mercantile Exchange. Heating oil for September delivery closed at 87.34 cents a gallon, up 1.8%, which represented a six-month high. Heavy demand from refiners has drained crude oil inventories to 24-year lows, and energy experts fear that heating oil supplies will be scant this winter. Higher oil costs have not shown up yet in national gasoline prices. The U.S. average price of self-serve regular gasoline fell 1.5 cents to $1.447 a gallon, the Energy Information Administration said Monday, based on a weekly survey of 800 gasoline stations. The California average for self-serve regular edged up 2/10 of a cent to $1.668 a gallon.