« Denmark has considerably large deposits of oil and natural gas in the North Sea and ranks as number 32 in the world among net exporters of crude oil[101] and was producing 259,980 barrels of crude oil a day in 2009 »
It seems I have underestimated the Danish oil reserves. However, oil export is a small fraction of its economy. I haven't been able to find an accurate figure, but according to Danmark statistik [1], it was about 8.17% of Danish exports in April 2014, which is very far from making Denmark into an oil-based economy like Norway is.
https://en.wikipedia.org/wiki/Denmark