SINGAPORE (APP) – Oil prices extended their gains to multi-month highs on Thursday following another drop in US supplies and the prospect of further disruptions to output from key producers Nigeria and Canada.

The commodity has almost doubled in price since falling near 13-year lows at the start of the year as a global supply glut has eased thanks chiefly to a weakening dollar, signs of a pick-up in the world economy and falling production from Nigeria and Canada.

On Wednesday the Department of Energy said US commercial stocks had fallen far lower than expected in the week of June 3, fanning talk that demand is improving in the world’s biggest oil consumer.

“The inventory has been dropping for three consecutive weeks, showing that the supply-demand relationship has leaned towards a balance,” CMC Markets analyst Margaret Yang wrote in a note.

At about 0645 GMT, US benchmark West Texas Intermediate rose 26 cents, or 0.51 percent, to $51.49 a barrel, its highest since July. Brent gained 14 cents, or 0.27 percent, to $52.65, its highest since October.

Expectations that the Federal Reserve will not raise interest rates until September at the earliest has put downward pressure on the dollar, making it cheaper to buy the black gold with other currencies.

The chances of output from Canada picking up in the near term are slim as fires in northern Alberta, the country’s main oil producing region, led to at least two companies shutting down production facilities. Canada is the biggest supplier of oil to the United States.

And in Nigeria, which is a member of the OPEC exporters group, rebels have rejected a truce offer from the government, fueling fears they will continue attacks on installations that have already halved the country’s output.