The last time they were at these levels or lower it was due to the financial crisis and the world economy slowing down. Some are now arguing in this thread that oil prices aren't low either. Rather that they have been high preceding this. So who knows... Lot's of opinions here for sure.
The oil to gas ratio has been the norm for 50 years to interpolate value when compared in units of heat rates. And by that comparison oil is "obscenely" overvalued. No conspiracies are really needed at this time...
Eventually they will go back up but the ratio between natural gas and oil should fundamentally be within a certain range. So nat gas prices could trade a lot higher and therefore oil prices could go up with them. Ultimately empirical data shows us there is a very strong correlation to oil prices and emerging market growth. So if you buy into higher oil prices then you better be extremely bullish on risk assets and emerging market growth. I'm not quite as bullish and think we might enter another recession before we get the next uptick in the credit expansion cycle.
Price wars against US NG companies - slowed global economic growth justifies the aggressive undercutting of competition.
I live in Oklahoma City and have a source from Continental Resources that told me OPEC is squeezing out the small players that specialize in the fracking industry. OPEC can go 30-45 months with being $30-$45 dollar oil per barrel. http://ecowatch.com/2014/11/27/opec-crash-fracking-industry/