Three Forks Formation -- Basic Review, Part II

This is a continuation of Three Forks Formation -- Basic Review, Part I

Basic Review, Part I, ended with the estimated ultimate recovery of oil from each of the six major Bakken/TFS-producing counties in North Dakota as calculated by the North Dakota Geologic Survey.

Here the numbers are again, the EURs as calculated by NDGS:

• McKenzie: 737 million boe is the estimated ultimate recovery of oil (EUR)
• Williams: 714 million
• Mountrail: 576 million
• Dunn: 475 million
• Burke: 375 million
• Divide: 200 million

Here are the number of acres of each county (approximate) determined by multiplying square mileage of each county by 640 acres/square mile:

• McKenzie: 1.831 million acres
• Williams: 1.374 million acres
• Mountrail: 1.242 million acres
• Dunn: 1.332 million acres
• Burke: 0.722 million acres
• Divide: 0.828 million acres

Dividing the number of acres in each county by the number of bbls EUR:

• McKenzie: 402 bbls/acre
• Williams: 519 bbls/acre
• Mountrail: 464 bbls/acre
  
• Dunn: 356 bbls/acre
  
• Burke: 519 bbls/acre
  
• Divide: 241 bbls/acre

Finally (last step) multiplying the above number by 640 acres will get you the EUR/section as calculated by NDGS:

• McKenzie: 257,602 bbls/section
  
• Williams: 332,402 bbls/section
  
• Mountrail: 296,754 bbls/section
  
• Dunn: 228,146 bbls/section
  
• Burke: 332,152 bbls/section
  
• Divide: 154,560 bbls/section

Some sections are going to be much more prolific than others, based on results of wells being reported since this boom began.  The NDGS figures are averages across the entire county.

In the better sections, EOG, WLL, CLR and others seem to agree that EUR will be somewhere around 750,000 bbls/section.  In the less prolific sections, they estimate closer to 400,000 bbls/section.

The NDGS figures about 2% recovery rate (EUR/OOIP).  CLR and other suggest they are getting at least 4% and maybe as much as 8% in some areas. Four percent doesn't sound like much, but it is double what the NDGS predicts.

Okay, now to put some of this into perspective. 

How much oil has come out of McKenzie County over the past 60 years -- yes, oil was first discovered in North Dakota in 1951? The cumulative total of oil from McKenzie Country from April, 1951, to May, 2010, totals: 395,992,836 barrels. (This is from a spreadsheet from the NDIC that I transcribed; at 16 pages I'm sure I made some typographical errors, but it's probably pretty close).

So, to date, "we've taken 396 million barrels of oil from McKenzie County, most of it prior to the current boom and from other formations than the Bakken. It's taken 60 years to produce that much.

The USGS estimates there is 737 million barrels of recoverable oil from the Bakken/Three Forks Sanish in McKenzie County (see above). Compared to Mountrail, I think McKenzie is behind in drilling the Bakken/TFS.

It will be interesting to review/compare these numbers with actual results ten (10) years from now.