The Oil Market Refuses to Heed Positive News
World energy markets are so concerned about strong demand and possible disruptions of supplies that oil prices finish higher, even though Saudi Arabia announces it has capacity to pump 1.3 million more barrels each day immediately if needed; low-sulfur crude oil for September delivery settles at $44.80 per barrel in New York trading, up 28 cents; International Energy Agency says world's use of oil will be even greater in rest of 2004 and in 2005 than it previously forecast, increasing pressure on producers to step up output at time when rising oil prices could slow world economic recovery; graph; photos (M)