Actully, almost all the oil producing countries produced oil much less than their capacity to keep the price at certain level. Recently, out of fear of the present crisis, Saudi Arab increased its production. As Saudies do not want world to concentrate on alternative energy resources.
That increase in production did not help at all as oil prices still kept climbing up. So, the present problem is not entirely due to short of supply. "Market is saturated with supplies" said by one of oil producing country's president. The problem is the fear about future supplies and the way stock trader do speculation.