Geologic Update Of The Three Forks -- January 25, 2018

For newbies: I'm starting to see more and more Three Forks first bench wells being reported, but still the mix is probably about 90% middle Bakken wells/production and 10% Three Forks first bench 9%. The other 1%: second and third bench.

Also for newbies, previously posted, September 26, 2013; these would be upper Three Forks/first bench wells: Three Forks wells in northeastern McKenzie County five times better than middle Bakken wells -- Lynn Helms.

There is a fourth bench, according to the commercial oil industry, but apparently the academic community sees three benches in the Three Forks, calling the second bench, the middle Three Forks. Or more likely, the lower Three Forks will be comprised of the 3rd and 4th benches.

The middle Bakken is book-ended by the upper Bakken and the lower Bakken, neither of which are significant oil producers, but rather the source rock for the producing payzones.

On the other hand, the Three Forks has four benches: the first bench, fairly well demarcated and a definite payzone; a second bench, now referred to by the academic community as as the middle Three Forks; and a third bench and fourth bench, of which relatively little is known.

That is preamble for this. DMR.ND.GOV has a link to a study of the middle Three Forks, the second bench. It will download as a pdf.  The article is written by Tiothy O. Neshieim. Data points (and this will get quite long):

Part I:

• the study area was pretty much centered between Watford City and Stanley
• wells #26990 and #22388 were in the center of the study area
• oil saturations were typically 25 - 50%; extending from the Bakken down through the base of the middle Three Forks (2nd bench)
• beginning in 2012, various operators began testing the middle to lower portions of the Three Forks formation (2nd, 3rd, and 4th benches)
• the prospective Three Forks reservoir horizons were informally subdivided into four benches, numbered 1 to 4 in descending order
• prior to 2012, most drilling was focused on the middle Bakken
• beginning in early 2015, the NDIC began tracking Three Forks wells
• since then, 180 wells have been drilled and completed in the middle to lower Three Forks formation;  the middle to lower Three Forks have cumulatively produced nearly 20 million bbls of oil ot date (this does not include the upper Three Forks, the 1st bench, which may be more prolific than the middle Bakken in some areas of North Dakota)
• the majority of those middle to lower Three Forks wells targeted the middle Three Forks (2nd bench) -- again, note, we are talking about the middle to lower Three Forks formation, not the first bench which is often referred to as the upper Three Forks
• a significant number of additional, pre-2015 middle to lower Three Forks horizontal wells are also present, but status and cumulative production volumes have yet to bet determined
• currently there is limited geological information available regarding the middle to lower Three Forks
• resource assessments of the Three Forks have ranged from 2 to 4 billion bbls of recoverable oil, but these assessments have been limited to the upper Three Forks [by the way, 2 to 4 billion bbls as an estimate of recoverable oil is so conservative as to be laughable]
• this study reports the preliminary findings of a recently initiated study on the origin and distribution of oil saturations within the middle Three Forks
• the author also examines oil saturations and hydrocarbon production in thee lower Three Forks (3rd and 4th benches)
• hydrocarbons present with the Three Forks are believed to be sourced from the overlying lower Bakken shale, which is considered to be a world class petroleum source rock

Part II:

• the second bench is the middle Three Forks, author
• contains similar rock types to the prolific upper Three Forks (1st bench)

Part III:

• middle Three Forks (2nd bench) oil saturations
• 50+ wells studied
• the middle Three Forks can be further divided into three areas based on oil sats and water sats
• 1st tier area, highest oil saturations: northeastern McKenzie to southeastern Dunn and southwestern Mountrail counties; almost identical to the upper Three Forks, the 1st bench
• a larger 2nd tier: lesser oil sats but still significant
• 3rd tier: water sats increase; oil sats decrease to less than 10%
• 1st tier: correlates with where the lower Bakken shale exists; 20' thick; has reached the greatest level of thermal maturity with respect to oil generation
• 2nd tier: correlates with thinner lower Bakken shale; less thermally mature, but still with the peak oil generation window
• oil saturations of the middle Three Forks appear to be primarily a function of thickness and thermal maturity of the lower Bakken shale
• wells drilled in middle Three Forks to date have mostly been in Tier 1 areas

From the article:

 

Thursday, December 7, 2017 -- More Truck Drivers Needed In Texas In 2018

"Pearl Harbor Day." This is an appropriate place for this story on Carl Vinson -- story sent to me by a reader.

North Dakota wells coming off confidential list today

Thursday, December 7, 2017: 32 for the month; 142 for the quarter

• 33208, 1,244, Whiting, Evitt 14-12-4TFHX, Truax, Three Forks, 39 stages; 9.3 million lbs; t6/17; cum 90K 10/17;
• 33134, 1,063, Liberty Resources, T. Haustveit E 156-95-26-3MBH, 27 stages, 8 million lbs, Beaver Lodge, t6/17; cum 99K 10/17;

Getty Center, LA: reports of fire engulfing the Getty Center seem to have been exaggerated. Radio report.

Al Franken update: pending

Jobs report and 4Q17 GDP forecast: link -- better jobs report than expected

• prior: 238,000
• consensus forecast: 240,000
• actual: 236,000
• 4-week average: 241,500 (down 750)
• 144th consecutive week claims remained below the 300,000 threshold, which is associated with a strong labor market 
• nonpayrolls probably increased by 200,000 in November after surging 261,000 in October 
• GDP Now forecast, December 5, 2017 -- 4Q17 forecast at 3.2%, down from 3.5% on December 1, 2017

Gasoline demand graph: link --

Houston: new US crude oil trading hub; competes with Cushing --WSJ --

• as US crude oil exports surge, analysts say Houston better reflects oil-price dynamics than Cushing
• much of the US crude oil destined for export bypasses Cushing completely and goes direct to Houston
• until recently, the price of WTI in Houston was about the same as the price at Cushing, plus the roughly $2-a-barrel cost of a ride south on a pipeline. But that difference has widened to more than $5 in recent weeks, as strong overseas demand pushed Houston prices higher.
• how bad is it?

“Cushing is becoming irrelevant,” said Philip Verleger, an energy economist who helped develop the Nymex oil futures contract in the early 1980s.

• not everyone agreess

Euan Craik, CEO Americas of Argus Media group, which compiles the Houston prices, said the two benchmarks are complements rather than substitutes. So far, there hasn’t been as much trading in a contract that only tracks Houston prices—most of the futures market activity is still linked to the Cushing price.

GE to cut 12,000 jobs in power business revamp: link here at Reuters -- mostly French, German, Swiss. GE rival Siemens [poster child for wind energy] is cutting about 6,900 jobs (about 2% of its global workforce)

Port of Vancouver oil terminal disapproved. Not unexpected. Like Hawaii, the northwest becomes more of an energy island. The good news: Washington State has plenty of hydroelectric power. For the archives; I'm not particularly interested. 

$60: JPMorgan's new "magic number" for shale oil -- Bloomberg via Rigzone --

• Permian: operators won't change course as long as WTO stays in the $45 - 55 range
• a one- to two-quarter run above $60 was the "consensus catalyst for another leg higher"
• with that said, some explorers say they plan to at a rig her or there, but very few mention rig drops
• JPMorgan expects production to remain "mostly flattish" -- industry copes with labor and equipment shortages
• for the archives: at the time this was posted, WTI has been trending down toward $56

So much for reform: it was Saudi Arabia's Crown Prince who bought a piece of art for almost one-half billion dollars.

***********************************

Back to the Bakken

Active rigs:

$56.09↓↓	12/7/2017	12/07/2016	12/07/2015	12/07/2014	12/07/2013
Active Rigs	53	39	64	188	193

RBN Energy: E & Ps face challenges in managing "last mile" logistics.

With frac sand use — and costs — on the rise in the Permian, a number of exploration and production companies (E&Ps) are becoming more involved in managing sand acquisition and logistics. It’s not an easy job, because even though a greater share of the frac sand used in Permian wells is expected to come from local, West Texas sand mines in the coming year, those “last mile” logistics — the delivery of sand by truck from the mine, plus unloading and storage of sand at the well site — are especially complex. Today, conclude our series on frac sand with a look at the challenges E&Ps face when they assume supply chain responsibility for sand.

E&Ps in the red-hot Permian and other U.S. shale and tight-oil and gas plays have had remarkable success the past few years in ratcheting down the cost of drilling and completing new wells and to increase hydrocarbon production per well. And, as they have gained a more nuanced understanding of their hydrocarbon resources, producers and their pressure pumpers have been implementing increasingly sophisticated and well-specific completion strategies to wring ever-increasing volumes of crude oil, natural gas and natural gas liquids from their wells. These gains have been particularly significant in the Permian, where E&Ps have largely figured out how to optimize production from the region’s multiple, stacked pay zones. Two key elements of their success are drilling longer horizontal wells or laterals (now often 7,500 or 10,000 feet, and sometimes longer) and intensifying completions with the use of more pressure, more frac sand per linear foot of lateral and more frac stages.

Trucking: this interesting note regarding truckers from today's RBN Energy article:

Frac sand truckers can (and do) put in a lot of hours. Federal Motor Carrier Safety Administration (FMCSA) rules limit truck drivers like those hauling sand in the Permian to a 14-hour workday and no more than 11 hours of that on the road — after that 14-hour mark is hit, a driver must take at least a 10-hour break. There’s also a weekly cap (no more than 70 hours) and after that mark is hit the driver must take a 24-hour break.

Drivers must maintain written logbooks to track their hours — officially known as “records of duty” (RODs) — so they can prove they’re abiding by the FMCSA limits, but as you might guess, an independent trucker making a lucrative hourly rate may be tempted to fudge his (or her) log hours. Well, starting in a few days (December 18, 2017), drivers will be required to install and use an Electronic Logging Device (ELD), which, as its name suggests, electronically tracks when and where a truck is driven, who’s driving it etc.

(Trucks that already have been using a much simpler automatic on-board recording device, or AOBRD, can continue using that until December 18, 2019; by then they will need to install an ELD.)

The ELD requirement will pretty much put an end to drivers putting in more than 14 hours a day or 70 hours a week, which means that even more drivers will be needed to replace the “lost” capacity enabled by the paper logging process.

As the driver capacity issue is further stretched, the law of supply/demand takes over and the trucking companies will likely need to offer even higher pay to attract more drivers to the Permian and other shale plays.

How to move frack sand, also from the linked article:

The industry has gravitated to two types of containerized solutions for the sand to minimize dust.  First, there are a number of metal sand box (“sand in a can”) solutions in which metal boxes are filled at the transload site or local mine with more than 20 tons of sand and trucked to the well site on a flatbed truck. These boxes can be unloaded quickly at the site with a large forklift truck and the sand then can be fed directly into the mixer with minimal dust. The second solution is to use mobile silos that are moved to each new well site. Sand is trucked to these silos via a pneumatic or bottom-dump truck with around 24 tons of sand in each truck and either moved via air pressure into the silo or dumped onto a mostly closed conveyor system. There are advantages and disadvantages to both containerized processes and the companies responsible for choosing the systems have preferences for which to use for each well situation.

The good news is that these containerized solutions to the silica dust problem may also improve the efficiency of frac sand deliveries — by reducing the time it takes to move sand from the truck.  The time that drivers spend waiting in line to make their deliveries will be trimmed as well. That, in turn, will increase the productivity of each driver (more deliveries per week) and hold down the need for more drivers. Innovation continues for all the possible solutions, with a focus on improving the cycle time for the truck at the well, on further reducing dust, on ensuring safety for the workers and on minimizing the need for more truckers.

Geology, the Devonian: a few items over the past few days have mentioned the Devonian. I'll probably re-post this at a stand-alone post, but I don't want to lose the link, so here it is:

• Overview of the petroleum geology of the North Dakota Williston Basin, North Dakota Geological Survey, undated, but appears to have been written in 2000; previously posted

Map of the day via Twitter. States with populations less than Los Angeles Counties:

US LNG export capacity: note how huge Sabine is --

Cold in Europe? Italy at pre-alert level for natural gas withdrawals, from Twitter:

Lodgepole Reefs, An Update -- December 5, 2017: Happy 21st Birthday -- Dinsdale 2-4

Disclaimer: in a long note like this, there will be typographical and factual errors. If this information is important to you, go to the source.

With regard to this subject (Lodgeple reefs) I welcome any comments from those in the oil industry who can add more information or correct me where I am wrong. 

Earlier this morning (or overnight) a reader asked what percent of Lodgepole wells are successful in the area southwest of Dickinson, ND?

This had to do with this well:

33997, dry, Freedom Energy Operating, LLC, Freedom Energy ND 1-15, Heart River, pool: Lodgepole; spud 10/2/17; from the permit, estimated TD = 9,950 TVD;

From the geologist's report: this well was targeting a Lodgepole reef:

Oasis Petroleum Freedom ND #1-15 [SE SE Sec. 15, T139N-R97W] is located ~6 miles West of Dickinson, North Dakota. Freedom ND #1-15 is situated within the Heart River Field in Stark County. A vertical hole targeting the porous Reef of the Lodgepole formation.  

It was a steep learning curve for me when I first learned about Lodgepole reefs. I discuss Lodgepole reefs at this post and that's where I will continue to track them. 

I don't know what the percentage is, but anecdotally (based on casual observations or indications rather than rigorous or scientific analysis), these are my thoughts:

• there is a difference between the Lodgepole formation and Lodgepole reefs
• to date, it appears that operators in North Dakota have only been successful hitting the Lodgepole reefs immediately west, southwest, and south of Dickinson, ND and inside city limits
• the farther one gets from Dickinson, ND, the less likely one will hit a reef
• some operators have targeted the Lodgepole formation north of Williston (I forget now how those have turned out) 
• once you leave the area west and southwest of Dickinson the likelihood of hitting a Lodgepole reef is pretty unlikely
• even in the area of the Lodgepole reefs it appears to be a real "hit or miss" (no pun intended) outcome
• Lodgepole reef wells are vertical (or directional/vertical) wells and are not fracked; very, very low expense to drill
• I am not quite sure what to think about horizontal wells (if there are any) that target the Lodgepole in the Dickinson area
• Looking at the "Lodgepole wells" west and southwest of Dickinson: I have only looked at a few of these wells; I assume they are all Lodgepole reef wells but my assumption could be wrong

One can see a number of Lodgepole wells at my "Monster Wells" link.

As a "case study," I looked at one Lodgepole well in the Dickinson area, #14213. I have blogged about this well on numerous occasions. From this post: "Denbury Onshore, LCC, may have the most productive well in North Dakota," posted March 27, 2011. This Lodgepole reef well is inside Dickinson city limits.

• 14213, 3,357, Denbury, Dinsdale 2-4, Lodgepole, Stadium, t12/96, cum 4.95 million bbls 9/17; it was shut in all of 10/17; full production profile is at this post.

Interestingly, the "most productive well in North Dakota" was just shut in two months ago. In its 21 years of operation, it has never been shut in for a full month, until now.

The scout ticket:

The graphics:

From the NDIC file:

Flashback: Williston Basin Petroleum Systems As Understood In 2000

Note: in a long note like this there will be formatting errors, typographical, and factual errors. Go to linked source if this is important to you.

I assume that I saw this paper years ago, and it's even possible I read some of it. LOL.

But now that I understand the Bakken a whole lot better and in light of Lynn Helms' recent comments, it is time to go through this article a lot more closely.

The author is Daniel M. Jarvie. The manuscript was submitted for publication in February, 2000. As a reminder, the North Dakota Bakken boom began seven years later. The North Dakota Bakken boom was preceded by a smaller, perhaps unnoticed by most, the eastern Montana Bakken boom, which began in 2000, about the same time this manuscript was submitted.

Jarvie gave his mailing address as Humble Geochemical Services, Humble, TX.

For newbies:

• 2000: a mini-Montana Bakken boom had just begun
• 2007: the North Dakota Bakken boom began

The Abstract

The lead sentence in the abstract is remarkable. It begins:

The Williston Basin has often been used as a model for petroleum exploration and production in basins around the world ...

Other data points from the abstract:

• carbonate source rocks in the Madison Group were overlooked for many years
• Jarvie came up with conclusions based on geochemical analysis of dead oils from 16 producing horizons (remember: Lynn Helms suggested 17 oil-producing horizons)
• the oils from these 16 horizons can be distinctly typed and correlated

His analysis would further elucidate the dominant Madison Group petroleum system in the Williston Basin, while also elucidating secondary petroleum systems including the Duperow, Red River, and Bakken-Lodgepole systems as well as other minor systems

• Madison Group:
• carbonate source rocks
• enriched in 6-carbon ring light hydrocarbons, toluene and methylcyclohexane
• while this 6-ring preference is generally thought to be indicative of terrestrially sourced oils, these oils are definitively derived from carbonate or marly shale source rocks
• Bakken oils:
• enriched in 5-carbon ring light hydrocarbons such as the alkylated cyclopentanes, which appears characteristic of a clay-rich, marine shale source
• Red River oils:
• enriched in normal paraffins and exhibit characteristic Ordovician-sources (G. prisca) oil fingerprints
• other unique petroleum systems:
• Duperow
• Winnipegosis
• Deadwood
• the single Spearfish oil groups with Madison oils
• Nisku oils are principally grouped with Bakken oils  
• Interlake oils are principally grouped with Red River oils

Introduction

The Williston Basin: an intracratonic, sag type Paleozoic basin, located on the western shelf of the North American Craton

Intracratonic basins are the classic type of sedimentary basin. Notable examples include the Williston, Michigan and Illinois basins of North America, the Maranhao basin of Brazil, and the Murzuk and Kufra. 

From Dr Abbas Mansour on sedimentary basins: The Williston basin is the classic example of an intracratonic basin. It contains some three kilometres of rocks of all periods from Cambrian to Tertiary, with notable gaps only in the Permian and Triassic. Sedimentation spanned a range of environments including fluvial and marine sands, reefal carbonates, evaporites and subwave- base pelagic muds. Deep-sea, turbidite and deltaic fades, igneous activity and shallow syndepositional faulting are all absent.

Prescient comment: "the impact of a new play can be dramatic"

Bakken-sourced Lodgepole oils had one year production rates accounting for 10% of the production totals in 1996 alone; this play was described by Lever and Anderson (1984) about 10 years prior to the major Lodgepole discovery in Stark County, ND

Lodgepole oils had one year production rates accounting for 10% of the production totals in 1996 alone 
 
Madison Group reservoirs account for 61% (750 million bbls of oil) of North Dakota's Williston Basin historical oil production (remember, this paper was published back in 2000)

Little attention has been given the source of Duperow oils even though Duperow reservoirs are the second highest producing horizon, exceeding Red River Foundation by about a percentage point

Combined Madison Group, Duperow, and Red River reservoirs account for over 80% of North Dakota's oil productioon

Bakken reservoirs account for 3.2% of production (remember, this paper was published back in 2000)

Oil typing and petroleum systems analysis in the Williston Basin were first published by Williams (1974) and Dow (1974) who detailed 3 petroleum systems as the Tyler, Bakken-Madison, and Winnipeg-Red Riverusing sterane biomarkers Grantham and Wakefield (1988) suggested that an effective source rock was present in the Mission Canyon Formation

Osadetz (1992) suggested and confirmed (1995) a Lodgepole source for Madison oils 

Price and LeFever (1995) described a "dysfunctionalism" in the hypothesized Bakken-Madison petroleum system based on quite different saturate and aromatic gas chromatographic data between the Bakken and Madison Group oils 

• using C7 light hydrocarbon data, Madison, Bakken, and Red River oils were typed and characterized as separate oil families (Jarvie, 1997, Obermajer, 1999)
• further correlation of an organic-rich Mission Canyon carbonate source source to various Madison oils was achieved using light hydrocarbons and biomarkers (Jarvie and Walker, 1997)  
• they also demonstrated the presence of organic-rich intervals throughout the Madison Group including 3 organic-rich Mission Canyon horizons (up to 14% TOC) in the Denielson #1 well in Sheridan County, MT 
• on the other hand, based on same criteria, they correlated the Lodgepole mound oil in the Conoco Kuntz well in Stark County, ND, to the underlying Bakken Formation, although organic rich False Bakken rocks have nearly identical fingerprints 
• while Osadetz (1992) suggest a Lodgepole source as opposed to Mission Canyon source (Jarvie and Walker, 1997) for Madison Group oils, there is, in part, some discrepancy over nomenclature
• for example, in Osadetz and Snowdon (1995), the Tilston Member is shown to be in the Lodgepole Formation, wherease in the US, the Tilston Member is placed in the lower Mission Canyon Formation (multiple studies, 1966, 1987)
• in addition, other intervals in the Mission Canyon Formation have high source potential such as the Richey Shale and other markers

The Madison

EXPERIMENTAL APPROACH FOR OIL TYPING

OBJECTIVES OF STUDY

Samples -- see linked source
Results -- see linked source

Prospective Williston Source Rocks

Madison Group oils: the thickness of these prospective source units range from 50 ft thick on the fringe of the basin to 200 - 300 ft thick in the central part of the Williston Basa detailed study of Madison sources in the central part of the Williston Basin has not yet been completed

Quantitative Gas Chromatographic Fingerprints, Yields, and Ratios

• paper describes the Ordovician oil set 
• the Madison Group oils have very low pristane-to-phytane ratios; whereas typical Bakken oils have values greater than 1.00  
• these data indicate several segregated families of oils following distinctive maturation trends
• the Madison, Bakken, and Red River oils are inferred to be derived from different source rocks  
• certain oils group with these 3 main groups including the Spearfish with Madison oils, the 4 Lodgepole and 4 Nisku oils with Bakken oils, and Interlake and Winnipeg oils with Red River oils  
• the single Madison oil plotting with the Bakken-Lodgepole oils is the Northlustre Field oil in Valley County, MT and is likely a Bakken or mixed source oil 
• there are large differences in sulfur contents among the Madison oils with oils in the northeastern part of North Dakota (Burke, Renville, Ward, and Bottineau counties) having the highest values 
• in general, high sulfur oils have lower API gravities 

In summary:

• Spearfish-Madison Group
• Lodgepole-Bakken-Nisku Group
• Red River Groups
• Madison-Bakken mixes
• Madison-Red River mixes
• Bakken-Duperow mix oil

Long, long discussion of the various oils -- see linked source

Skip ahead to seals

SEALS

Interesting, interesting, interesting:

The lack of correlation of Madison oils with Bakken oils except in certain highly faulted locales demonstrates that seals are effective between the Bakken and Madison as well as other horizons.

But then this: wherever overpressuring occurs within the Bakken, it is effectively a pressure-sealed system

Benzing and Shook (1996) hypothesized that pressure seals form in the presence of interstitial gas and the Bakken has been shown to generate gas at low maturity.

In addition, an overpressured system has significantly increased storage capacity (Holm, 1998) enabling such a system to retain more of its generated products, which will either be expelled in the presence of fractures or further cracked to light hydrocarbons 

CONCLUSIONS

1. Madison oils are distinct from Bakken oils indicative of different sources. This is based on 6-ring preference in the C7 hydrocarbons shown by Madison oils which is evident in Madison source rocks as well as biomarker data, the latter of which demonstrates that Madison Group oils are derived from carbonate or marly shale source rocks

2. Mixing of Madison and Bakken oils does not appear to be extensive in the US Williston Basin (unlike int he Canadian Williston Basin where there is a continuum suggesting high input of Bakken oil into Madison reservoirs

3. A single Spearfish oil from McHenry County, ND, correlates with Madison Group oils

4.  Lodgepole mound, Bakken, and most of the Nisku oils studied are Bakken-sourced oils with the Lodgepole oils being lower maturity oils than typical Bakken-produced oils

5. Some Madison Group oils in this study are mixed Bakken-Madison sourced oils. These oils are form E. Poplar (Roosevelt County, MT) and McGregor Field (Williams County, ND). The McGregor oil may have some Duperwon input in lieu of, or in addition to, Madison input

6. Duperow and Winnipegois oils are different from each other and other oils, but show considerable variabilty perhaps due to mixing or commingling of production; it is likely that there are separate sources for these oils

7. Red River oils are rich in paraffins

8. see linked source

9. see linked source

10. A single Tyler oil is likely derived from a marly shale source within the Tyler or Heath formations; these oils have been shown to be quite variable, however

Note: marly shale --  Marl or marlstone is a calcium carbonate or lime-rich mud or mudstone which contains variable amounts of clays and silt. The dominant carbonate mineral in most marls is calcite, but other carbonate minerals such as aragonite, dolomite, and siderite may be present.

The Pronghorn Member, Bakken Formation (MIssissippian-Devonian)

In the geology portion of file reports, the geologist will occasionally mention the various lithofacies of the Pronghorn Member of the Bakken Formation. This is a bit of background. A huge "thank you" to Don for sending me the link.

The Pronghorn, from GEO News, July 20, 2017. Ichnology Applied to the Pronghorn Member, Bakken Formation (Mississippian-Devonian). This link will open a PDF on your desktop: https://www.dmr.nd.gov/ndgs/documents/newsletter/2017Summer/Ichnology%20Applied%20to%20the%20Pronghorn%20Member%20Bakken%20Formation.pdf

I did not note the ichnology; if interested, go to the source, linked above.

History:

• formally proposed by Julie A LeFever and others in 2011
• defined as the strata underlying the Lower Member and overlying the Three Forks Formation
• had previously been included in the Three Forks and referred to as the "Sanish sand"
• significant unconformity at the top of the Three Forks section
• lithologies within the Pronghorn section are mappable and consistent with those observed within the Middle Member

Location:

• located throughout the Williston Basin
• divides easily into proximal and distal bed
• proximal bed primarily in the southwestern portion of the basin
• distal portion is more centrally located
• proximal beds are associated with production

The geology:

• Three Forks Formation
• an alternating sequence of apple green and tan dolomudstones and claystones
• Pronghorn Member
• Bakken Formation
• can be divided into five (5) lithofacies, in ascending order from A-E
• focus of this paper: middle section B of this member

A. Basal Sandstone

• lowermost sandstone lithofacies
• fine- to very fine-grained quartz sandstone
• difficult to identify with certainty on wireline logs

B. Dolomitic Mudstones with Storm Beds

• upper portion of the interval: dolomitic mudstone with thicker storm beds of very fine- to fine-grained quartz
• the upper portion of the interval becomes significant when examining production
• although the porosities are similar throughout the interval, the upper portion of the lithofacies appears to have better permeability than the underlying portion

C. Lime Mudstone

• thin, medium brown-grey mudstone to siltstone

D. Limestone

• a medium grey, nodular-bedded limestone
• represents an open marine environment
• again, difficult to identify on wireline logs

E. Silt

• the uppermost lithofacies has been previously referred to as the "Bakken silt" and is possibly the distal equivalent to the proximal lithofacies -- the sandstone, storm beds, lime mudstone, and limestone
• organic values (TOCs) are significantly less than the overlying Lower Member of the Bakken formation

Lower Member of the Bakken

• a dark brown to black organic-rich shale
• the Lower Member was deposited in a restricted marine setting allowing for the stratification of the water column and the development of anoxic bottom waters

Relationship of Facies to Production

• minor changes in the depositional environment of the "B" beds appear to have an effect on production; although porosity over the section is consistent, the permeability decreases from the upper section to the lower section
• the silt interval of the Pronghorn should negatively affect production
• however, the silt portion performs better as a reservoir because of the higher percentage of oil saturation to total fluids and therefore produces less water

Two More DUCs Reported Thursday -- April 5, 2017

Active rigs:

	4/5/2017	04/05/2016	04/05/2015	04/05/2014	04/05/2013
Active Rigs	49	29	94	192	187

Three permits renewed:

• Abraxas (3): three Yellowstone permits in McKenzie County

Two producing wells (DUCs) reported as completed:

• 29949, 1,390, CLR, Hendrickson 7-36H2, Elm Tree, 4 sections, t3/17; cum --
• 30335, 430, CLR, Hendrickson Federal 3-36H2 Elm Tree, 4 sections, t2/17 cum --  

The Hendrickson wells are tracked here. 

Three wells come off the confidential list Thursday:
26279, SI/NC, HRC, Fort Berthold 148-94-36C-25-4H,  McGregory Buttes, no production data,
32756, SI/NC, XTO Bear Creek 31X-3F2, Bear Creek, no production data,
33042, drl, North Range Resources, Placid 28-2V, Rough Rider, no production data,

Note: from an earlier post --

• 32883, drl, North Range Resources, LLC, Placid 28-1V, Rough Rider, target: Duperow, Mission Canyon, Souris River; spacing 160 acres; a "vertical well" but the target bottom hole will be 1301 feet north of well and 1058 feet east of well; no production data,

Placid target: sundry form on file requesting to drill an additional 124' deeper than their permitted depth, so they could log through the entire Three Forks formation. However, the Mission Canyon is still the target.

From the file report:

Graphic of two of the Placid vertical wells in Rough Rider oil field:

Oasis Ceynar Update; Claystone and Shale -- March 20, 2017

Updates

May 10, 2017: the geologist's report is finally posted. #32801 is a first bench well.

March 21, 2017: in the update immediately below, the reader says the original Patsy well just to the south of the Ceynar 11T is a Second Bench producer. If I am correct, the reader is talking about #20689. It took a lot of "digging" at the file report to find it, but yes, that's accurate, the target was the second bench for this well:

• 20689, Oasis/Zenergy, 1,202, Patsy 5-8HTF, Siverston, 25 stages, 2.8 million lbs , t11/12; cum 148K 1/17;

I've talked about the "history" of the middle Bakken/Three Forks first bench/Three Forks deeper benches, but I won't repeat that here.

March 21, 2017: a question was raised whether #32801 was a first or second bench well. I think you can skip the entire original post. A reader clears it up (a big "thank you"to the reader):

The Ceynar 11T is a First Bench Three Forks well.  The claystone (shale) marks the bottom of the First Bench. The top of the target zone is 11,291 ft.  If it were a Second Bench, the horizontal leg would be drilled at about 11,340 ft TVD.

By the way, the original Patsy well just to the south of the Ceynar 11T is a Second Bench producer. 

The Patsy was drilled by Zenergy and it now owned by Oasis.  It’s horizontal leg runs

south through sections 5 and 8. 

Oasis’ naming pattern is as follows:  T (First Bench); T2 (Second); T3 (Third) B (Middle Bakken).

Original Post

Update: on the March 31, 2017, daily activity report, the name of the well for #32801 was corrected (see below; correction has been made; mostly like a first bench Three Forks well)

Over at the "Discussion Group" a reader asked about:

• 32801, drl, Oasis, Ceynar 5298 43-32 11T, Banks, 

This well should be a Three Forks well. The reader wonders whether this is a second bench Three Forks well. I don't know yet, but still looking. Maybe someone has more information.

The application stated the target was a first bench well, but the name of the well was slightly different in the application:

• Ceynar 5298 43-32 11T, Banks,

Note: no "T" after the 43-32; now  "T" has been added to the "43-32." I don't recall seeing this nomenclature before. I don't see this "T" on any of the documents in the file report. I suppose it could be a typographical error but I've never seen a typographical error in the legal name of a well on an NDIC scout ticket (I have seen typographical IP errors).

The most recent sundry form received in February, 2017, still shows this as "Ceynar 5298 43-32 11T" and no change in the name. I suppose it's possible the scout ticket with "43-32T" is a typographic error. 

From the planning report, this looks like a second bench well:

By the way, the reader noted a new marker (a new formation/sub-formation) below the target landing: Claystone 1st. I don't recall seeing Claystone 1 before.

Googling "claystone" reveals that this appears to be simply a general name for type of sedimentation that is found between different payzones?

Random Update Frack Sand Pricing -- February 22, 2017

Cost Of Frack Sand Rising Faster Than Forecast -- Goldman Sachs

John Kemp via Twitter

• anecdotal 
• currently $30 - $40 / ton frack sand
• frack sand market "tightening more quickly than we [Goldman Sachs] previously envisaged
• partly due to winter-seasonally closed wet plants in Wisconsin/Illinois
• tightness may ease in spring (March/April) when wet plants restart
• spot prices now $30 - $40 / ton; higher than prior forecast of $25 / ton; up from only $20 / ton 4Q16
• supply of fine grade sand (100 mesh, 40 x 70) is particularly tight
• prior estimate: a peak price of $35 / ton; now Goldman Sachs "sees upside risk to our estimates"
• frack sand companies followed by GS: SLCA, EMES, FMSA/SND

Back-of-envelope:

• typical Bakken well: 4 million lbs on low side; 10 million lbs on high side
• 2,000 to 5,000 tons
• x $35 = $175,000 in frack sand per 10-million-lb well

******************************************** 
Wyoming Geology

Annals of the Former World

John McPhee

c. 1998

DDS: 557.3 MCP 

Winner of the Pulitzer Prize

Book 3: Rising From The Plain, p. 281 - p. 427

• Rawlins, Wyoming, I-80, at the Continental Divide
• autochthonous geologist: "one who studies rock that has not moved"
• Cretaceous: many fathoms underwater; the Stable Interior Craton -- from the Gulf of  Mexico to the Arctic Ocean; Cretaceous  -- hundred million years ago; oldest formation where oil could be found
• coastal swamps would have been like the Florida Everglades, the peat fens of East Anglia (where we were stationed with the USAF for three years), or the borders of the Java Sea
• Cretaceous swamps were particularly abundant in this part of Wyoming
• now, filled with coal
• alternating with the shale, was limestone, sea-bottom lime
• Creataceous stratovolcanoes (Idaho) spewed ash with selenium
• most plants ignore selenium
• exception: wood asters require selenium to germinate; once they take selenium up, they convert it to a form that nearly all plants will, in turn, take up
• selenium-contaminated plants are eaten by sheep and cattle
• concentrated selenium destroys an enzyme that transmits messages from brains to muscle: blind staggers -- seen in cattle and sheep; humans can also be poisoned by selenium
• Frontier Sandstone: one of the great oil sands in the Rocky Mountain region
• Mowry shale: organic mud of the Cretaceous seafloor; wherein the oil of the Frontier could have formed
• bentonite: AKA mineral soap; can adsorb water up to fifteen times its own volume; known as gumbo
• bentonite: sold worldwide; used in adhesives, automobile polish, detergent, and paint
• bentonite: in drilling "mud" of oil rigs, sent down the pipe and through apertures int he bit to carry rock chips to the surface; it sticks to the walls of the drill hole and keeps out unwanted water
• bentonite: Indians drove buffalo into swamps full of bentonite

1905, Rawlins, Miss Ethel Waxham, graduate of Wellesley College, Massachusetts; her field, classical studies; expert horse rider

Lost Soldier, WY: oil discovered in 1916

• it would yield the highest recovery per acre of any oil field that has ever been discovered in the Rocky Mountains
• payzones: 
• Cambrian Flathead sandstone
• Mississippian Madison limestone
• Tensleep sands of Pennsyvanian time
• Chugwater, red sands of the Triassic
• Morrison, Sundance, Nugget (celebrated formations of the Jurassic)
• Cretaceous Frontier
• discoverer: young graduate from Princeton University; put the term "sheepherder anticline" in the geologic lexicon: a "sheepherder anticline" is a particularly obvious anticline; to avoid being seen mapping such an anticline, a smart Princeton geologist would masquerade as a sheepherder

The outcrop around Rawlins: a greater spread of time than any other suite of exposed rocks along I-80 between NYC and SF; and a good deal more time than one sees in the walls of the Grand Canyon, where the clock stop stops at the rimrock, aged 250 million years

• at Rawlins: back into the Archean Eon and up to the Miocene epoch, 2,600 million years old
• when forming, it would have been near the equator
• the dunes would have been just under, or just rising above the water
• the dunes above water would have been much like the Libyan desert
• long discussion on the Rawlins Uplist -- so much of the earth's history had happened to be here; no one knows why
• Wyoming has a disproportionate percentage of American geology 
• shield rock: Precambrian craton; copper, diamonds, iron, and gold
• long discussion on Wyoming geologists; perhaps the best in the country
• mentions Robert LeRoy Parker and Harry Longabaugh (Butch Cassidy and the Sundance Kid) -- p. 304
• Pine Bluffs: along the Wyoming-Nebraska state line; I've traveled through that area often on my trips back and forth between Texas and North Dakota
• Jackson Hole, p. 366; "hole" was a term used by the earliest whites to describe any valley that was closely framed by very high mountains; the story of David Jackson; ran trap-lines in the 1820s

This is all I will do on Book 3: just too much stuff. This would be a great beach book.

Re-Posting A Bit Of Geology -- February 22, 2017

This was previously posted, but re-reading it today, I found it so interesting, I want to re-post it:

Annals of the Former World

John McPhee

c. 1998

DDS: 557.3 MCP 

Winner of the Pulitzer Prize

This is not an easy book to read. The paragraphs are way too long. Most pages have one, one-and-a-half, or two paragraphs. The writing is meandering. It is not tight. But, wow! Talk about an interesting look at geology in the 1980s and 1990s and how far we've come.

Plate tectonics was new; it was all the rage; and there were still detractors. The theory was not necessarily widely accepted. 

The table of contents and the index suggest there is only one full page devoted to shale oil, but what an incredible page. The author writes from Wyoming:

At all moments in the history of Lake Gosiute, it was replete with organic life, from the foul clouds of brine flies that obscured its salty flats to the twelve-foot crocodiles and forty-pound gars in the waters at their widest reach. For this was Wyoming in the Eocene, and the lake at varying times were ictalurid catfish, bowfins, dogfish, bony tongues, donkey faces, singrays, herring.

The American Museum of Natural History has a whole Gosiute trout perch in the act of swallowing a herring, recording in its violence two or three seconds from forty-six million years ago. In the museums' worldwide vertebrate collection, roughly one fossil in five comes from Wyoming, and a high percentage of those are from Gosiute and neighboring lakes. Around the shores were red roses and climbing ferns, hibiscus and soapberries, balloon vines, goldenrain. The trees would generally have been recognizable as well: pines, palms, redwoods, poplars, sycamores, cypresses, maples, willows, oaks. There were water striders, plant hoppers, snout beetles, crickets. The air was full of frigate birds. Dense beds of algae matted the shallows.

In all phases through the eight million years, quantities of organic material mixed with the accumulating sediments and (sic) are preserved with them today in the form of shale oil.

On the far side of the Uinta Mountains was another great lake, reaching from western Colorado well into Utah. Lake Uinta, as it has come to be called, and Lake Gosiute and several smaller lakes left in their shales a potential oil reserve estimated at about one and a half trillion barrels. This is the world's largest deposit of hydrocarbons. It is actually nine times the amount of crude oil under Saudi Arabia, and about ten times as much oil as has so far been pumped from American rock. 
 
Distinct in the long suite of cuts at Green River were the so-called mahogany ledges, where oil shale is particularly rich. They looked less like wood than like bluish-white slabs of thinly bedded slate.

Oil shale always weathers bluish white but is dark inside, and grainy like wood. The thinner the laminae, the higher the ratio of organic material. [This explains the Bakken.] The richest of the oleaginous flakes -- each representing the sedimentation of one year -- were fifteen-thousandths of a millimetre (sic) thick. [David] Love [of the USGS] dropped some hydrochloric acid on the rock, and the acid beaded up like an arching cat.

"It's actually kerogen," he said. "It converts to high-paraffin oil. It's not like Pennsylvania crude."

To mining engineers, oil shale had presented and as yet unsolved and completely unambiguous problem: how to remove the shale oil without destroying the face of the earth. So far, three principal methods had been considered.

None of the three mentioned sounded like hydraulic fracturing; and none of the three have been commercially successful.

The one-and-a-half-trillion-barrel estimate was somewhat extravagant, because it included every last drop -- referring, as it did, to all shale with any content of kerogen. In the richer rock -- in the shales that contained twenty-five to sixty-five gallons of oil per ton -- were nor more than six hundred billion barrels.

That would do. That was more petroleum in place than all the petroleum produced in the world to date. Love remarked that oil shale had been "trumpeted to the skies" but, with the energy crisis in perigee, both government and industry were losing interest and pulling out. Temporarily pulling out. Sooner or later, people were going to want that shale. 

The essays were written in 1981, 1983, 1986, and 1993.

Another Bust For US Government Sale Of Gulf Of Mexico Leases -- August 24, 2016

I thought I had blogged about this earlier, but can't find it now. The results are now in, and it doesn't look good -- or it looks great -- depending on what side of the fence you stand on.

The AP is reporting:

The federal government says three companies are bidding on acreage in the Gulf of Mexico off Texas — and they've made a total of 24 bids on 24 tracts out of more than 4,000 offered.

That's even fewer than last year's sale, which was the smallest ever for the western Gulf.

Last year, five companies made $22.7 million in high bids — also one per tract, on 33 tracts.

The three companies bidding are BP Exploration and Production Inc., BHP Billiton Petroleum Inc., and Exxon Mobil Corp. BP bid on 13 tracts, BHP on nine tracts and Exxon Mobil bid on two.

Wow, lots of story lines there.

***********************************

A Note For The Granddaughters

Annals of the Former World

John McPhee

c. 1998

DDS: 557.3 MCP 

Winner of the Pulitzer Prize

This is not an easy book to read. The paragraphs are way too long. Most pages have one, one-and-a-half, or two paragraphs. The writing is meandering. It is not tight. But, wow! Talk about an interesting look at geology in the 1980s and 1990s and how far we've come.

Plate tectonics was new; it was all the rage; and there were still detractors. The theory was not necessarily widely accepted. 

The table of contents and the index suggest there is only one full page devoted to shale oil, but what an incredible page. The author writes from Wyoming:

At all moments in the history of Lake Gosiute, it was replete with organic life, from the foul clouds of brine flies that obscured its salty flats to the twelve-foot crocodiles and forty-pound gars in the waters at their widest reach. For this was Wyoming in the Eocene, and the lake at varying times were ictalurid catfish, bowfins, dogfish, bony tongues, donkey faces, singrays, herring.

The American Museum of Natural History has a whole Gosiute trout perch in the act of swallowing a herring, recording in its violence two or three seconds from forty-six million years ago. In the museums' worldwide vertebrate collection, roughly one fossil in five comes from Wyoming, and a high percentage of those are from Gosiute and neighboring lakes. Around the shores were red roses and climbing ferns, hibiscus and soapberries, balloon vines, goldenrain. The trees would generally have been recognizable as well: pines, palms, redwoods, poplars, sycamores, cypresses, maples, willows, oaks. There were water striders, plant hoppers, snout beetles, crickets. The air was full of frigate birds. Dense beds of algae matted the shallows.

In all phases through the eight million years, quantities of organic material mixed with the accumulating sediments and (sic) are preserved with them today in the form of shale oil.

On the far side of the Uinta Mountains was another great lake, reaching from western Colorado well into Utah. Lake Uinta, as it has come to be called, and Lake Gosiute and several smaller lakes left in their shales a potential oil reserve estimated at about one and a half trillion barrels. This is the world's largest deposit of hydrocarbons. It is actually nine times the amount of crude oil under Saudi Arabia, and about ten times as much oil as has so far been pumped from American rock. 
 
Distinct in the long suite of cuts at Green River were the so-called mahogany ledges, where oil shale is particularly rich. They looked less like wood than like bluish-white slabs of thinly bedded slate.

Oil shale always weathers bluish white but is dark inside, and grainy like wood. The thinner the laminae, the higher the ratio of organic material. [This explains the Bakken.] The richest of the oleaginous flakes -- each representing the sedimentation of one year -- were fifteen-thousandths of a millimetre (sic) thick. [David] Love [of the USGS] dropped some hydrochloric acid on the rock, and the acid beaded up like an arching cat.

"It's actually kerogen," he said. "It converts to high-paraffin oil. It's not like Pennsylvania crude."

To mining engineers, oil shale had presented and as yet unsolved and completely unambiguous problem: how to remove the shale oil without destroying the face of the earth. So far, three principal methods had been considered.

None of the three mentioned sounded like hydraulic fracturing; and none of the three have been commercially successful.

The one-and-a-half-trillion-barrel estimate was somewhat extravagant, because it included every last drop -- referring, as it did, to all shale with any content of kerogen. In the richer rock -- in the shales that contained twenty-five to sixty-five gallons of oil per ton -- were nor more than six hundred billion barrels.

That would do. That was more petroleum in place than all the petroleum produced in the world to date. Love remarked that oil shale had been "trumpeted to the skies" but, with the energy crisis in perigee, both government and industry were losing interest and pulling out. Temporarily pulling out. Sooner or later, people were going to want that shale. 

The essays were written in 1981, 1983, 1986, and 1993.

*********************************

Paraffins

From wiki:

The trivial (non-systematic) name for alkanes is paraffins. Together, alkanes are known as the paraffin series. Trivial names for compounds are usually historical artifacts. They were coined before the development of systematic names, and have been retained due to familiar usage in industry.

Cycloalkanes are also called naphthenes. It is almost certain that the term paraffin stems from the petrochemical industry. Branched-chain alkanes are called isoparaffins. The use of the term "paraffin" is a general term and often does not distinguish between pure compounds and mixtures of isomers, i.e., compounds with the same chemical formula, e.g., pentane and isopentane.

A Picture Of Me Without You, Lorrie Morgan

Scientific Study Which Helps Explain Production Differences Across The Bakken

A huge "thank you" to a reader for sending "us" a superb presentation on the geological and technological aspects and their influence on production in the Bakken. The study comes from the Colorado School of Mines; the presentation is very current, dated May 2, 2013, but the results are based on older wells. The link will take you to a PDF:

http://wbpc.ca/+pub/document/2013_presentations/Theloy%20WBPC%20Regina%202013_Cosima%20Theloy_for%20posting.pdf

Slide 8 is particularly interesting for many reasons. The graphic shows the average EUR among ten (10) subdivisions in the Bakken, based on township boundaries. The average EURs (in 1,000's; 2010 to 2011):

• Sanish Parshall: 632
• Ft Berthold: 569
• Bear Den: 536
• South Nesson: 506
• Rough Rider: 466
• Bailey: 459
• Elm Coulee (Montana): 433 (2001 - 2003 data)
• North Nesson: 393
• Mondak: 283
• St Demetrius: 209

The data on number of frack stages vs those subdivisions seems to be inconclusive.

Data regarding type of proppant used:

• Sand: 614 wells
• Sand and ceramic: 78 wells
• Ceramic only: 74 wells

Based on a very limited data set, a mixture of 2/3rds sand and 1/3rd ceramic appears more effective than either along.

The maturity boundary of the Bakken/Three Forks:

• northern boundary: eastern half of Divide County
• eastern boundary: splits Mountrail County in half; diagonally splits Dunn County in half
• southeastern boundary: includes the western third of Stark County
• western boundary: well into Montana; off of Williams, McKenzie, Billings, and Golden Valley counties inside the boundary limits

With the commentary, I am unable to interpret data on slide 18 which investigates whether the Parshall is self-sources, or a result of migration.

Slide 19 is one of the more interesting slides: graphic depicting oil / oil + water.

Slide 20 is also interesting: the sweet spots / uneconomic spots tend to correlate with oil / oil +water.

Slide 22 should satisfy mineral owners to the east of Williston and explain why Stockyard Creek has been such a good field. Epping field should also be a great field.

Slide 23: back to oil / oil +water. Elm Coulee ≠ Bear Den ≠ Rough Rider.

New Wells Reporting: Posted -- Just a Reminder, Nothing New -- The Bakken, North Dakota, USA

Wells reporting IPs or going to DRL status yesterday have been posted, on "New Wells Reporting." Based on IP only (and that's just one data point), one could be disappointed with the Whiting well in Zenith oil field in Stark County.

• 19926, 161, WLL, Roller 21-26TFH, Zenith, Stark County

I don't see the frac report yet at the well file. I may have missed it. 

As you may recall, the some of the highest prices per mineral acre have been in Zenith oil field.

The target for this well was the Three Forks. The seam targeted was about 9 feet below the point at which they entered the Three Forks, if I read the file correctly. I would assume they would try to put the horizontal pretty much in the middle of the targeted formation, making the seam about 20 feet thick.

At this point, I am more interested in the Tyler formation. According to the report, they entered the Tyler at 8,151 feet. They entered the Kibbey Lime at 8,552 feet. If it's as simple as subtracting these two numbers (and I don't know if it is), the Tyler was 400 feet thick in this area.

What follows is beyond my base of understanding but over time the data may make sense. The report stated the following:

• Tyler formation: background gases at the top of the Tyler averaged around 17 units, then increased up to 60 - 196 units at the top of the formation. After around 120 feet, background gases decreased back down and averaged around 17 units through the remainder of the Tyler.
• Kibbey Lime: units averaged 22 - 28.
• Charles: background gases averaged 17 - 73.
• Mission Canyon: averaged 28 - 62 units
• Lodgepole: averaged 22 - 67 units
• Middle Bakken:  averaged 190 units
• Three Forks:  averaged around 150 - 250 units, with connection gases reaching as high as 348 units

For a discussion of what this all means, this is one source; this is probably a better source, but lots of reading. (In fact, the latter source, is quite approachable.)

The volume of gas will increase with effective porosity of the formation; see this long post for background.

Anyway, enough of this. Just some more data points to help me understand the reports.

Definitions:

• Porosity is a measure of how much of a rock is open space. This space can be between grains or within cracks or cavities of the rock.
• Permeability is a measure of the ease with which a fluid (water in this case) can move through a porous rock.

From "World of Earth Science," at eNotes:

Porosity is the ratio of the volume of openings (voids) to the total volume of material. Porosity represents the storage capacity of the geologic material. The primary porosity of a sediment or rock consists of the spaces between the grains that make up that material. The more tightly packed the grains are, the lower the porosity. Using a box of marbles as an example, the internal dimensions of the box would represent the volume of the sample. The space surrounding each of the spherical marbles represents the void space. The porosity of the box of marbles would be determined by dividing the total void space by the total volume of the sample and expressed as a percentage.

The primary porosity of unconsolidated sediments is determined by the shape of the grains and the range of grain sizes present. In poorly sorted sediments, those with a larger range of grain sizes, the finer grains tend to fill the spaces between the larger grains, resulting in lower porosity. Primary porosity can range from less than one percent in crystalline rocks like granite to over 55% in some soils. The porosity of some rock is increased through fractures or solution of the material itself. This is known as secondary porosity.

Permeability is a measure of the ease with which fluids will flow though a porous rock, sediment, or soil. Just as with porosity, the packing, shape, and sorting of granular materials control their permeability. Although a rock may be highly porous, if the voids are not interconnected, then fluids within the closed, isolated pores cannot move. The degree to which pores within the material are interconnected is known as effective porosity. Rocks such as pumice and shale can have high porosity, yet can be nearly impermeable due to the poorly interconnected voids. In contrast, well-sorted sandstone closely replicates the example of a box of marbles cited above. The rounded sand grains provide ample, unrestricted void spaces that are free from smaller grains and are very well linked. Consequently, sandstones of this type have both high porosity and high permeability.

Three (3) New Permits -- Bakken, North Dakota, USA

Update

Some folks might be concerned about the small number of permits a couple of days this past week. Not to worry; this will take care of itself. I haven't checked lately but I think we are on track for 1,750 new permits this year.

It sure beats a permitorium.

Original Post

Daily activity report, September 9, 2011 --

Operators: Whiting, Liberty Resources, and Legacy Oil

Fields: Sanish, and two wildcats

This is the second permit for Liberty Resources; this one is northeast of Williston in a pretty good area.

Newfield reported an awesome well today:

• 20108, 2,789, Newfield, Lawlar 151-98-31-30-1H, McKenzie County

Other than that, pretty unexciting report except for this bit of trivia:

NDIC File No: 20361     API No: 33-061-01668-00-00
Well Type: ST     Well Status: DRL     Status Date: 3/9/2011
Wellbore type: Directional
Location: NWNE 11-156-94     Footages: 735 FNL 2510 FEL     Latitude:
48.354399     Longitude: -102.730415
Current Operator: HESS CORPORATION
Current Well Name: EN-PERSON OBSERVATION- 11-31
Elevation(s): 2177 GL     Total Depth:       Field: BIG BUTTE
Spud Date(s):  3/9/2011
Casing String(s): 9.625" 1902'
Completion Data
   Pool: THREE FORKS     Status: DRL     Date: 3/9/2011 

What do you notice?  Pool: Three Forks.  Generally speaking, all wells targeting Bakken formations (3) and Three Forks formations (1 - 5), the pool has been administratively designated the "Bakken Pool."  See hearing dockets, and see numerous other file reports in which wells targeted the Three Forks and the pool was designated as "Bakken Pool."  Occasionally, we have seen "Sanish Pool."

Continued Confusion: Bakken and Three Forks Sanish -- the Definitive Answer -- February 17, 2010

Summary

The "Bakken Pool" is an administrative term that includes the Bakken formation and the Three Forks Sanish formation.

The NDIC website shows the accumulated totals of oil production from the "Bakken" and the "Bakken/TFS."  I assume the Bakken is limited to the Bakken formation in the "Bakken Pool"; and, the "Bakken/TFS" is limited to the TFS formation in the "Bakken Pool."

Geo News, July, 2010: the Bakken potential.

The Original Post

I have posted this several times: there is confusion over "Bakken" vs "Three Forks Sanish." This is the best answer I have seen: the NDIC and the USGS consider the oil coming from the "Bakken" and the "Three Forks Sanish" to be coming from the "Bakken Pool." That's why on the daily activity report, the pool is always listed as "Bakken" when the well targets the Bakken formation or the TFS formation. [Update, October 14, 2010: click here to see an exception. Is this new, evolving, or did I miss similar wells earlier?]

And that's the key: "formation." The Bakken formation is composed of the Upper, Middle, and Lower Bakken members/units, all separate strata. Likewise, the Upper TFS and the Lower TFS are separate strata.

Formations, members/units, and strata are all geologic terms.

On the other hand, "Bakken Pool" is an administrative term. The USGS and the NDIC prefer to lump these five (5) formations together as one pool (see below -- it makes sense).

The five formations can be very, very thin in some areas, and it is very possible a) the geologist is not 100% sure which formation the tip of the drill is in; b) a long lateral may pierce more than one formation; and/or, c) the administrative paperwork to date may not always be "perfect," and it might be difficult, expensive, and even unnecessary to sort out exactly what formation the lateral is in, especially when the formations may communicate in some localities.

The NDIC defines the Bakken Pool as 50 feet above the upper Bakken limit and 50 feet below the lower Bakken formation line. One needs to see the "completion report" to see which formation(s) was (were) targeted. Most of the reports linked at my site do not include the completion report, but the report that is provided after the well comes off the confidential list. [Update, July 6, 2013: for the past year, operators have been requesting, and NDIC has been granting alterations to the definition of the stratigraphic limits of the Bakken/Three Forks.]

*****

The Geology

The stratigraphic nomenclature varies, for example:

Southeastern Saskatchewan

Periods: Mississippian and Devonian

Groups: Three Forks and Saskatchewan

Formations: Bakken, Big Valley, Torquay (the Three Forks group)

Formation: Birdbear (the Saskatchewan group)

North Dakota

Periods: Mississippian and Devonian

Groups: "Bakken Pool" and Jefferson

Formations: Bakken and Three Forks (the "Bakken Pool" group)

Formation: Birdbear (the only formation in the Jefferson group)

*****

Of course, the next question that arises is this: at the NDIC website, cumulative oil production is broken down by "formation" on one of the pages. The NDIC has broken out two "formations" as 1) the Bakken; and 2) the Bakken/TFS.  It appears for North Dakota this is logical: as noted above, the "Bakken Pool" group is composed of the Bakken formation and the Three Forks Formation. But it is confusing that they label it as the "Bakken/TFS." They don't do that with other formations, such as the Red River which is part of the Madison Group. 

*****

Here's another recent discussion regarding this issue; the discussion begins well down into the thread once you get there. 

I have recently posted that EOG may be planning to drill three wells from one pad (in the Parshall), the wells targeting, respectively, the Middle Bakken, the Upper Three Forks Sanish, and the Lower Three Forks Sanish.

Interestingly enough, the 1990 boom in North Dakota targeted the Upper Bakken.

So, there you have it. Within the "Bakken," it sounds like there could be five formations: Upper, Middle, and Lower Bakken; and, the Upper and Lower Three Forks Sanish (more correctly referred to as unit 1- 6).

*****

Note: one of the pioneers in the Bakken, Marathon Oil (MRO), considers the "Bakken" to be composed of five distinct units: the Lodgepole; the upper, middle and lower Bakken; and, the Three Forks (Sanish).

*****

On another note, the Spearfish/Madison Pool lies directly above the Bakken Pool. The Spearfish/Madison Pool is much thicker, extending from the shallower Spearfish, all the way down to the Madison, which lies directly above the Bakken formations. Back in 2006, Julie LeFever published an article which included data to suggest that the Madison Pool does not "leak" oil into the underlying Bakken. [October 31, 2017: that link is now broken. This PDF discusses the Bakken as "we" knew it back in 2005. The html is at this link.]

*****

According to a research paper by Roy Neset, Jr., Department of Geosciences, Fall, 2009, the source rocks for the middle Bakken member are the upper Bakken shale and the lower Bakken Shale; the source rock for the Three Forks Sanish member is the lower Bakken shale. Neset provides data to suggest that the lower Lodgepole Formation, which overlies the upper Bakken shale source rock, could be an economically viable oil-producing zone. An abbreviated synopsis of that research can be found here.