Two weeks ago, we took a look at the red-hot Haynesville shale. I'd now like to direct your Foolish attention northward, to another resource play that's turning plenty of heads.

The Bakken formation is located in the Williston Basin, which stretches from North Dakota and Montana on up into Canada. Like the Haynesville, the Bakken is a shale play that was uneconomic until recent advancements were made by folks like Halliburton (NYSE:HAL) in the areas of horizontal drilling, fracture stimulation, and completion technology. Unlike the Haynesville, the Bakken is primarily an oil accumulation.

The U.S. government pegs the technically recoverable prize on the U.S. side at three or four billion barrels. As we'll see, that estimate may significantly understate the size of the play.

Just to get a point of terminology cleared up, there's a big difference between so-called "oil shale" and the crude oil-bearing sedimentary rock that Bakken producers are tapping.

The massive oil shale resource out in the Rockies' Green River Basin does not contain crude oil. It's actually kerogen, a pre-cursor to crude that hasn't cooked in the earth's oven long enough. We would need to simulate millions of years of natural heating and pressure in order to bring that stuff up to par. For that reason, the economics are less than compelling.

The Bakken formation, on the other hand, contains real live Texas tea -- fully cooked and ready to be refined. EOG Resources (NYSE:EOG) has identified a similar oil play in the Fort Worth Barnett Shale. These sorts of plays are proving highly profitable -- hence the industry hoopla.

That brings us up to the recent spate of updates out of the play.

Continental catches the wave
No company is more synonymous with the Bakken than Continental Resources (NYSE:CLR). Continental is the largest leaseholder in the play, with about half a million acres. As oil has soared and drilling results have made the Bakken's potential clearer over the past year, Continental's shares have more than quadrupled.

Well, the hits just keep on coming. A recently completed well has reportedly flowed at roughly 1,100 barrels of oil equivalent per day. While well short of some of EOG's monster results, that's still a pretty serious well by onshore U.S. standards. For some context, The Wall Street Journal recently reported that the biggest producer in the lower 48 is a 1,600 barrel-per-day Swift Energy (NYSE:SFY) well. Initial production rates tend to drop off sharply, but Continental still has a strong result there.

What's more important is that this well didn't even target the Bakken. It sits in the Three Forks/Sanish formation, which lies below the Bakken. That government estimate I mentioned before? It doesn't include this additional target, which may in time prove to be a completely separate reservoir.

Brigham's bragging rights
While Brigham Exploration (NASDAQ:BEXP) controls far less acreage than Continental, the smaller E&P's leasehold stacks up impressively against bruisers like Marathon Oil (NYSE:MRO) and EOG. It's hard to disagree with the company's claim of having the position with the greatest impact.

Brigham has also released some fresh well results, including an early flow rate of around 727 barrels of oil equivalent. In addition to internally funded prospects like this one, Brigham participates in lots of third-party wells as a minority partner. This helps to spread both capital and risk around. Not that Brigham's being shy with capex: The firm has now hiked its 2008 Williston budget by 127%.

XTO says tally ho
Speaking of ponying up, XTO Energy (NYSE:XTO) just closed its purchase of a serious swathe of primo Bakken territory. Apparently the firm wasn't content with a mere 350,000 acres. XTO has also gone ahead and scooped up an additional 100,000 for a mere $115 million. At a little over $1,000 an acre, that's peanuts. Of course, the acreage is unproven, but it wouldn't take much for this additional acquisition to prove a bargain in hindsight.

XTO, whose leasehold could soon leapfrog that of Continental, is also talking about the potential of the Three Forks/Sanish formation. It would behoove Bakken observers to monitor results of future wells that are completed in this emerging play. The Bakken could go from just blooming to booming.

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