U. S. crude oil futures ended down more than 5 percent, the biggest single-day percentage loss for front-month crude since April, as government data showed a surprisingly large build in crude oil inventories last week. U. S. natural gas futures also traded down on Wednesday, amid continued mild weather across the mid-section of the nation, weaker crude futures, a quiet tropical front and record high inventories.

The API said on Tuesday that for the week ended crude stocks rose 4.1 million barrels, gasoline supplies fell 47,000 barrels and distillate stocks rose 116,000 barrels.

Qatar, one of OPEC's smallest producers, has notified at least three Asian term buyers that it will supply its Land crude oil at full contracted volumes for September, unchanged from August levels, trade sources said.

The U. S. National Hurricane Center said Wednesday it did not expect any tropical development during the next 48 hours.

Temperatures in key gas consuming cities New York and Chicago were seen mixed, with New York above normal this week, but Chicago still mostly below normal, and highs seen topping out in the high 80s degrees Fahrenheit in New York, according to forecaster DTN Meteorlogix.

Crude oil may decline further on the back of built in inventory and concerns about speculation limits as CFTC’s stance has been very aggressive. We may witness some more long liquidation in energy complex.