How Thick Must A Payzone In The Bakken Be, To Be Economically Viable

[Note: the discussion below concerns the Williston oil field, a small field in the Williston Basin, although references are made to the entire Bakken in the Williston Basin.]

A reader asked:

How thick does a layer need to be in order for a well to be worth producing?

To the best of my knowledge, there is no published information on this. There would be too many variables. (For example, if the price of oil goes to $1,000/bbl, then even poor wells [now] would become more valuable.)

However, having said that, it seems I have seen reports where the middle Bakken was less than 10 feet thick (sometimes as little as four feet thick) in some places where the horizontal was drilled. It always amazes me they can keep the bit in a seam that narrow.

I also believe that I read somewhere that the upper Three Forks, though more variable in distribution, is generally much thicker than the middle Bakken. This would go along with what else the reader had to say:

I have been told that the Three Forks is 75 feet thick in the Williston oil field.

The reader noted that the first well to target the Three Forks in the Williston oil field, #23746, Statoil's Mark 4-9 2TFH, spud in May, 2013, is still on DRL status.

But note this, the well only 150 feet away, targeting the middle Bakken:

• 22384, 2,910, Statoil, Mark 4-9 1H, Williston oil field, t5/12; cum 157K 10/13:

Pool	Date	Days	BBLS Oil	Runs	BBLS Water	MCF Prod	MCF Sold	Vent/Flare
BAKKEN	10-2013	31	1812	1991	1504	2694	2268	426
BAKKEN	9-2013	30	6059	6293	4384	6553	6294	259
BAKKEN	8-2013	31	4418	5715	3989	4279	3869	410
BAKKEN	7-2013	31	5711	5516	4461	5708	5676	32

Although the well was on-line for 31 days in October, 2013, its production dropped from 6,000 bo the month before to less than 2,000 bbls in September, 2013, suggesting that the well was choked back or taken off-line, perhaps to complete the TFH well to the east.

My hunch is we will see the results of the Mark 4-9 2TFH well in another month or so, having been completed/tested in October or early November, 2013. Just a hunch. 

To get back to the original question, the thickness of the seam. All things being equal, the thickness of the seam is very, very important, but so is TOC, permeability, porosity which I wrote about a long time ago. However, if the upper Three Forks in the Williston oil field is 75 feet thick that is worth noting; in my book, that is huge. The middle Bakken in the same area might be 20 feet thick. I looked at the well file but couldn't find an easy answer to how thick the middle Bakken was at the Mark 4-9 1H location.

Some other links of interest:

• "The middle Bakken is good; but the Three Forks is better." -- Mike Filloon 

• Thickness: whereas thickness in Bakken and Eagle Ford  comparatively thin (20 - 100 feet in the Bakken; 75 to 300 feet in Eagle Ford), some seams are extraordinarily thick in California (500 feet to 3,500 feet). Note the "thinnest" California seam is five times the thickness of the thickest Bakken seam.
• Continental in 2011 cut six cores of the entire vertical thickness of the Three Forks formation, which is 180-270 ft thick under its acreage, over a distance of 115 miles north to south. The cores revealed that the formation has up to four separate benches of dolomite that contain oil.

I have never thought about how thick a seam needs to be for an well to be economically viable. I assume the operator has a pretty good idea going into an oil field what the thickness will be based on earlier wells, seismographic studies, etc. Wildcats would not have the offset wells, of course.

The Red River in the Bowman area: said to be 3 - 6 feet thick, with EURs of 300,000 bbls, and probably one-third to one-half the cost of a middle Bakken well.

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A Note to the Granddaughters

As regular readers know, I am Apple fanboy #3 (I own no stock in AAPL; never have, never will). I have owned practically every desktop/laptop retail version of the Apple computer line. I had the original iPad, and now the second version (still awful old), and my wife has an iPhone. I do not have a smart phone.

Maybe it's just me, but does it seem like the only computer company the media follows closely for new developments is Apple? Except for a new Surface tablet by Microsoft, I am unaware of any new computer gadget that the masses are eagerly awaiting.

Now, I see that there is talk that Apple will bring out a LARGER iPad. That's a hoot. Every time Apple comes out with something, it seems to be thinner, smaller, and lighter. Now we actually might see something that is LARGER.

The LARGER iPad would be targeted to the pre-school, kindergarten, and elementary education market. I've always thought the original iPad and the mini iPad were really too small for the younger set. Kindergartners have less hand-eye coordination and a larger "desktop" makes sense.

It's also possible Apple will replace the 11-inch MacBook Air with the larger iPad. Incredible.

I see AAPL did nicely on the market today, with approval to sell iPhones to a gazillion Chinese. Hackers. LOL.