Officially, fundamentals may not matter so much for oil prices. But there is a flurry of economic data, and comments from Big Oil chiefs, that explains why crude prices could take a beating in the short term.

US government data on Wednesday showed another increase in U.S. crude and gasoline stocks, a sign of weak demand. Crude inventories swelled 5.1 million barrels, while analysts expected stocks to drop by 1 million barrels.

That followed less-than-inspiring US durable goods figures showing that demand for refrigerators, cars and the like fell in June for the first time in three months, another sign that the economic recovery has gone walkabout, if not AWOL.

Prices for crude oil futures took it on the chin, falling about 4% to $63-and-change a barrel. And bosses at two big British oil and gas companies are providing a bearish chorus.

BP chief executive Tony Hayward said Tuesday, after his company’s weak earnings, that BP saw “little evidence of any growth in demand and expects the [economic] recovery to be long and drawn out.”

After releasing weak second quarter earnings Wednesday, BG chief executive Frank Chapman said weak global gas demand was forcing the company, whose fortunes rest mostly on natural gas, to reduce its 2009 oil production target by about 3%.

Shell and Exxon are scheduled to report earnings Thursday and Chevron is slated for Friday. Exxon’s boss Rex Tillerson has already said he doesn’t see much reason to be bullish based on the demand he’s seen. What will we hear this week?