North Dakota and the Bakken by County

Looking at North Dakota oil production by county, and historical production by county, gives a better  perspective of what is happening in the Bakken and the rest of North Dakota than just looking at total production.

The data is available here: ND Historical Barrels of Oil Produced by County You will notice it says:(Confidential Wells are Not Included). However the total North Dakota does include confidential wells. And I have made adjustments for the confidential wells. The adjustment for March and April came from the NDIC here: State Summary Report April 2014.
Bakken Counties

The above chart is after adjustment for confidential wells. Even the lowest producer of the big four, Dunn County, outproduces the rest of North Dakota combined.

McKenzie

McKenzie was up 7,168 barrels per day after adjustment this month.
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Oil Field Models, Decline Rates and Convolution

This post is by Dennis Coyne

The eventual peak and decline of light tight oil (LTO) output in the Bakken/ Three Forks play of North Dakota and Montana and the Eagle Ford play of Texas are topics of much conversation at the Peak Oil Barrel and elsewhere.

The decline rates of individual wells are very steep, especially early in the life of the well (as much as 75% in the first year for the average Eagle Ford well), though the decline rates become lower over time and eventually stabilize at around 6 to 7% per year in the Bakken.

What is not obvious is that for the entire field (or play), the decline rates are not as steep as the decline rate for individual wells. I will present a couple of simple model to illustrate this concept.

Much of the presentation is a review of ideas that I have learned from Rune Likvern and Paul Pukite (aka Webhubbletelescope), though any errors in the analysis are mine.

A key idea underlying the analysis is that of convolution. I will attempt an explanation of the concept which many people find difficult.

At Wikipedia there is a fairly mathematical presentation of the concepts which often confuses people.  There are a couple of nice visuals to convey the concept as well see this page.

In the visual below a function f (in blue) is convolved with a function g (in red) to produce a third function (in black) which we could call h where h=f*g and the asterisk represents convolution, just as a + symbol is used to represent addition.

Convolution of box signal with itself2.gif
Convolution of box signal with itself2” by Convolution_of_box_signal_with_itself.gif: Brian Amberg
derivative work: Tinos (talk) – Convolution_of_box_signal_with_itself.gif. Licensed under CC BY-SA 3.0 via Wikimedia Commons.

I think the best way to present convolution is with pictures. Chart A below shows a relationship between oil output (in barrels per month) and months from the first oil output for the average well in an unspecified LTO play.

This relationship is a simple hyperbola of the form q=a/(1+kt), where a and k are constants of 13,000 and 0.25 respectively, t is time in months, and q is oil output.

Chart A is often referred to as a well profile. The values for the constants were chosen to make the well profile fairly similar to an Eagle Ford average well profile. EUR30 is the estimated ultimate recovery from this average well over a 30 year well life.

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Texas RRC Report April Production Data

The Texas Rail Road Comission has released their latest report with oil, gas and condensate production for April. The RRC data is always incomplete however and takes many months for the all the data to trickle in. The below chart shows that problem.

Texas RRC-EIA

The data is barrels per data with the EIA data through March and RRC data through April. The EIA has Texas C+C data is highly linear for the 10 months June 2013 through March 2014, increasing at 48 kb/d for 4 months, 41 kb/d for one month then 49 kb/d for the last 5 months.

The EIA has Texas C+C increasing at an average of 48.6 bp/d each month for the last two years. I think that is a little high. I think the production has been increasing at close to 43 kb/d each month but with a recent slow down in that increase.

Texas C+C

All Texas RRC June report data is through April. The RRC does not combine Crude with Condensate so I have to add the two. But here you can see the problem. Each month the reported data increases with the latest months showing the largest increase. However even if this is the case, the latest month should show an increase almost equal to the final total increase for that month. That was the case in the April Report, (January to February), but not the case for the last two reports.
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The EIA’s Drilling Productivity Report and Other News

The EIA just released its latest Drilling Productivity Report which is a report on all major shale plays in the U.S. All the data below, unless otherwise noted, is in barrels per day.

Three Plays

The EIA includes the Permian production as shale or light tight oil production. No doubt some tight oil is produced in the Permian but I think most Permian oil is conventional oil.

Total Shale Oil

Total shale oil production from all six shale plays. However I believe perhaps one million barrels of this is conventional production.
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