I think it squares rather well with what's happened in global economies (and with changing expectations with regard to them) over the last 4 years. When it seemed that things might fall completely apart - that the world might end - in the second half of 2008, oil crashed big time. We saw a massive over-correction from the previously heavily-bloated prices. Then, when it seemed that we'd survived and the world wasn't going to end, oil prices recovered. Oil prices climbed based on optimism in portions of the global economy (e.g. China and emerging markets, and even mildly improving conditions in the U.S.). When worries about China creeped in, or when concerns about Europe came to the forefront, or when prospects here in the U.S. looked down, oil prices receded.
A number of things have affected oil prices, both acutely and chronically. A flood of liquidity, risk aversion with regard to equities, and meaningfully nonexistent real returns on safe havens like Treasuries, have combined to push money into the oil market. Supply-side concerns or prospects have entered the equation from time to time to push oil prices one way or the other. Those effects I would not deny. But the primary, consistent, underlying driver of price action in the oil markets over the last few years has been the perceived state of the global economy - indications, expectations, hopes, and fears with regard to it. Oil prices have, to a large extent, functioned as a surrogate for global economic expectations - with a few supply-side fear effects thrown in occasionally to keep things interesting.
The crashing oil prices that we've seen over the last month have mostly been the result of growing concerns about Europe - the disconcerting notion that, after a couple of years of efforts to stave off disaster, the #### may actually be getting close to hitting the fan. And concerns about China slowing down are getting more play.
Over the past couple of years I've followed the price action in oil fairly regularly. It's gotten to the point that I can pretty much tell whether the overnight news out of Europe and Asia was generally good or generally bad - or rather, generally taken in a positive or negative light - before I even get out of bed and make my way to my desktop computer to catch up on what that news is. I wake up, reach for my iPhone or iPad, and open a basic financial markets app that, among other things, shows me what oil is trading at. If it's down a meaningful amount, I can be fairly sure that the news out of Europe is pessimistic. If it's up a meaningful amount, I can be fairly sure that the news out of Europe is optimistic. Occasionally I get surprised to find out that the movement can be attributed to a supply-side concern or prospect (e.g. intensified turmoil in some oil producing nation). But more often than not oil prices move in lock step with global economic sentiment, or based on news affecting some important segment of the world's economy. The correlation is quite strong and has, over time, become undeniable. As I've said, and you've suggested, there are other issues and dynamics in play; but it seems to me that the ever changing state of expectations regarding the global economy has been the omnipresent driver.
EDIT:
Today's example: I wake to see that WTI is down another $1.51 and Brent another $1.73. Why? Probably, to a large degree, this...
Weak China PMI exacerbates bearish sentiment for shares, euro
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