Unitization and How Many Wells In One Section / One Spacing Unit in the Bakken? -- North Dakota, USA

A lot of folks have asked me over the past two years, how many wells can "they" put in a spacing unit, or how many wells can "they" put in a section in the Bakken? How about 14 wells in one 2560-acre spacing unit (essentially one well every 180 acres).

In the August, 2011, NDIC hearing dockets, here is one example: 

Case 15373, BR: Dimmick Lake-Bakken; Johnson Corner-Bakken; 12 additional hz wells on a single 2560-spacing unit and increase the stratigraphic definition of the Bakken Pool, McKenzie (this amounts to a well every 180 acres, if you include the two that are already there)

This is case # 15373. Burlington Resources will request that it be allowed to place as many as 12 "additional" wells on a single 2560-acre spacing unit. The 2560-acre spacing unit will be composed of two 1280-acre spacing units that already exist: one in Dimmick oil field, and one in Johnson Corner oil field. Specifically sections 28 and 33 in T151N-R96W; and, sections 4 and 9 in T150N-R96W.

These four sections are contiguous and run north-south.

There are already two producing wells in this (if approved) 2560-acre unit:

• 17680, 463, BR, Denali 31-28H, spudded 10/17/08; Dimmick Lake; 83,000 bbls to date
• 18225, 625, BR, Norman 1-9H, spudded 11/16/09; Johnson Corner; 85,000 bbls to date

Neither of these wells is all that spectacular. The IPs were nice, but not spectacular, and neither well has yet reached 100,000 bbls cumulative production yet.  As of June, 2011, the most recent reporting period, neither well is yet on a pump; both are flowing on their own. Both were taken off-line in May and June, suggesting a work-over, a pump, or something else.

The fields are good fields but they are not in the best Bakken (like the Sanish).

I don't know how unitization plays out but I've been told that before unitizing a field, and preparing the field for secondary and then tertiary enhanced oil recovery (water flooding; CO2 injection), one needs to maximize the number of wells going into the field.

I've talked about this before. It appears that fracturing is effective only to about 500 feet (radius) / 1,000 feet (diameter) with the well bore at the center. A section is a mile square, so to effectively fracture the entire section, one could place three to five horizontal wells. With two wells already there and requesting as many as 12 "additional" wells, one would have as many as 14 wells in this one 2560-acre spacing unit.

Note, that in the August hearings, BR is requesting to unitize the Lost Bridge-Bakken field, even though the producing wells in that field are predominantly CLR's. The Johnson Corner well above (#18225) was originally a CLR well, but is now operated by BR. There is obviously a close working relationship between CLR and BR as we move closer to unitization in the Bakken.

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Case 15379 is even more peculiar:

15379, QEP: Heart Butte-Bakken, create one 2560-acre unit; 12 hz wells; Dunn, McLean Counties. The 2560-acre spacing unit will be composed of two 1280-acre spacing units that already exist: both are in Heart Butte oil field and all four are under the river, or very near the river. Specifically sections 10, 11, 14, and 15 (forming a square) in T149N-R91W.

This is what is peculiar: according to the GIS map server, there are NO wells in any of these sections. Not even any permits yet. So, 12 wells in an area that has no wells yet. Very strange, indeed.

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Case 15375 is similar, but there are two wells already there producing:

15375, BR: Pershing-Bakken; North Fork-Bakken; 12 additional hz wells on a single 2560-acre unit; amend the stratigraphic definition of the Bakken pool, McKenzie. The 2560-acre spacing unit will be composed of two 1280-acre spacing units that already exist: one unit is in Pershing oil field; one is in North Fork oil field. The units are sections 4, 9, 16, and 21 in T149N-R96W; these four sections are contiguous, running north-south.

There are already two producing wells in this (if approved) 2560-acre unit:

• 17432, 156, BR, Curtis 1-4H, spudded 12/7/08; Pershing oil field; 84,000 bbls to date
• 17340, 805, BR, Saddle Butte 11-16H, spudded 2/25/09; North Folk; 43,000 bbls to date

Neither has a pump; both continue to flow.  Again, these are nice fields, but nothing spectacular.

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So, I certainly don't understand it. This is what I see:

• BR has a request into unitize a Bakken field, Lost Bridge
• These 2560-acre units are all BR units
• I've been told that before one unitizes a field, one maximizes number of wells in the field
• The producing wells on both 2560-acre units with producing wells are still flowing on their own; no pumps (four wells altogether; all flowing; spudded a couple of years ago)
• The wells are  not that spectacular based on IPs or cumulatives to date, but they continue to flare despite being spudded years ago (albeit only a small amount; most natural gas is collected/sold)