The last weekly average prices of the Organization of Petroleum Exporting Countries (OPEC) dropped to $66.80 per barrel, showing a reduction of $1.3 compared to the previous week, said the Vienna-based cartel Monday.

OPEC weekly average oil prices reached the peak value of $72.04 a barrel this year at the first week of August, but it has been showing a downward trend with oscillation.

On the five trading days of last week, OPEC daily average oil prices had only a rebound of $0.17 on Tuesday (September 22), while it kept falling for the other four days. On the last two trading days, it had even the daily reductions of respectively $2.75 and $1.12.

All of these corroborated the concerns from investors, who have been worrying that the rebound of demand for international crude oil may not be as strong as previously expected.

Last week, the news of Iran’s missile tests had stimulated oil prices for a while, but it did not halt the slide in oil prices. On the other hand, the slight increase in U.S. dollar exchange rate against euro caused the pressure on oil prices to a certain extent.

In addition, according to the figures, till August this year, OPEC’s crude oil output had been consecutively increasing for 5 months.

The OPEC daily average crude oil production of August amounted to 29.45 million barrels, representing 0.95 million barrels more than the demand expected in the latest OPEC monthly report for OPEC crude oil in world market in 2009.

According to the figures from the British institution for crude oil market analysis “Oil Movements,” in these 4 weeks to September 10, the daily shipping volume in OPEC crude oil is 22.49 million barrels, 0.16 million barrels more than the previous 4 weeks.

As the approach of the peak oil demand of Northern Hemisphere in winter, the institution expected that the amount of OPEC crude oil shipments may further increase in the next few months.

Therefore, despite the adequate supply in international oil market, the increasing strong expectation of world economic recovery, as well as the weaker U.S. dollar, the future basic trend of international crude oil prices may fluctuate with wide range.

(Xinhua News & Rigzone)