OPEC Secretary General Abdalla El-Badri said Thursday it was not economically plausible for oil producers to invest when the price of a barrel is below $70 per barrel, according to CNBC.

He said he did not think $50 would allow investment in the future.

I think we can live with 75, 85, 90 dollars, more or less, but we don't want to see a very high price because it's not to our benefit, El-Badri said in an interview with CNBC in Vienna, ahead of the organization's quarterly meeting.

Also today, Saudi Arabia's oil minister said Wednesday that oil prices may surge to about $75 a barrel by the end of 2009 on signs that demand is recovering in Asia, Bloomberg reported.

Crude prices on Wednesday increased to a six month high of $63 a barrel as investors speculated that the global economy may improve and demand for oil will go up.

Members of the Organization of Petroleum Exporting Countries supply about 40 percent of the world's oil. OPEC will meet on Thursday in Vienna to decide on oil output targets. The organization is expected to maintain current levels.