If you’ve had interest in shale-oil, you likely know names like Cabot Oil and Gas Corp. (NYSE:COGB), EQT Corp. (NYSE:EQTC) and Chesapeake Energy Corp. (NYSE:CHKC). These, after all, are some of the major players in U.S. shale production. At least they have been up to now.Related: 7 OIL STOCKS TO DUMP FROM YOUR PORTFOLIOThe Way Fracking Has BeenThe afore-mentioned companies and others in the space have drilled hundreds of wells called DUCs. DUCs are actually uncompleted wells. Once the price of oil justifies the next step, a DUC is fracked and real production begins.Fracking is as much art as science. It takes skill, trial and error and time to produce usable oil or natural gas. The trial and error part results in a lot of failed attempts, but over time some companies have developed the ability to extract enough energy from the ground to make a profit.New Kids On The BlockMeanwhile, as oil prices hover in the 40’s, though admittedly up a bit recently – major traditional oil producers like BP PLC (NYSE:BPC), Exxon Mobil Corp. (NYSE:XOMC) and Chevron Corp. (NYSE:CVXC) have found themselves in need of a financial infusion.This has led to those companies trying their hand at shale oil production. That’s because the projects they traditionally run costs multiple billions of dollars, far more than $40 per barrel oil will support.Solving The Shale RiddleThe main problem for big players like BP is that they don’t really know how to coax oil and natural gas out of shale – at least not like the smaller, more nimble producers. If BP, Exxon Mobil Corp. and others could figure it out, their reasoning goes, it could be profitable.This would help them maintain production levels. Unfortunately, failure could move them even further behind.The Big QuestionThe riddle to be solved – for big oil companies and for shale producers – is who will win the battle? Will shale producers continue to rule the roost or will big oil come in and by sheer force drive them out?Investors, deciding what type of stocks to put in their portfolios, want to know the answer before they commit one way or the other.Related: ANALYSTS ON OIL STOCKS YOU SHOULD CONSIDER BUYINGIf You Can’t Beat ‘Em, Buy ‘EmSome analysts and advisors have suggested that big oil – i.e., BP PLC, Exxon Mobil and Chevron – will end up acquiring the shale companies and the smart move is to get in on the action before big oil makes its move.It may have started when Whiting Petroleum Corp. (NYSE:WLLC) (of North Dakota’s Bakken shale basin) put itself up for sale this past March. The question, as before, is whether the price of oil will rise enough so that other shale producers can stay intact or will go the way of Whiting.