Thursday, May 2, 2013

OBSERVATION 3: USGS Needs To Improve on Style: Slide 17 Legend

A better graphic -- A huge thank you to a reader; see comments. Now, why couldn't the USGS have done this in the first place? The link:


Original Post

This post refers to the USGS PowerPoint presentation for the 2013 Assessment of the Bakken/Three Forks 

At slide 17, the USGS provides a graphic of the relative size of the various basins of continuous oil reservoirs, such as the Bakken, in the United States, to include Alaska. If one is trying to downplay the size of the Bakken, this is pretty successful.

Each basin/locality has a green "dot" varying in size based on the size of the reservoir. The USGS uses four dots to represent four "sizes":
  • less than 0.1 billion bbls
  • 0.1 to 0.5 billion bbls
  • 0. 5 to 2.0 billion bbls
  • greater than 2.0 billion bbls
That was fine when the largest continuous reservoir, the Bakken, was estimated to be 3.6 billion barrels back in 2008. But with the new estimate, the graphic needs to be updated.

Take a look at the graphic (slide 17 at the link). There is not a whole lot of difference in the size of the green "dots" for the Permian, the Western Gulf, and the Williston Basin. In fact, a newbie glancing quickly at this one slide would not be all that impressed with how much bigger the Williston Basin is compared to the Permian or the Western Gulf based on the graphic or the size of the dots.

But then look at the numbers:
  • Permian Basin (Midland-Odessa): 0. 51 billion bbls
  • Alaska North Slope (Prudhoe Bay): 0.94 billion bbls
  • Western Gulf (Eagle Ford) Basin: 1.73 billion bbls
  • Williston (Bakken/Three Forks) Basin: 7.38 billion bbls
The Williston Basin, at 7.38 is more than 4x greater than the Western Gulf (Eagle Ford). And then, get this: the Williston Basin's continuous oil reservoir is almost 15 times larger than the Permian Basin (Midland-Odessa).  The "green dot" overlying North Dakota should be twice as big as it is.

Having said all that: my hunch is that the estimate for the Western Gulf (Eagle Ford) continuous reservoir is significantly underestimated, and will be revised upward in the next assessment.


  1. If you compare the Williston Basin to the Permian Basin in that graphic, based on the proportions of the green dots the Williston would only have about 0.75 billion barrels of oil. Similarly, the smallest dot (the one labeled "0.01") has a diameter of 16px. If you started with that, and adjusted the other dots proportionally, the the dot for the Bakken would have a diameter of 11800px, which is more than 6 times larger than the width of the entire image (image size: 1862x1210 px).

    I made a somewhat crude edit of the graphic to display the dots proportionally to the size of the resource. You can check it out here:

    (Semi-trivial note: For a couple of the smallest dots I rounded the diameter up to the next integer even if the decimal was less than 0.5 just be cause the dots are hard enough to see as it is already. For example, the 3 "0.04" dots should have a diameter of 1.24px but I rounded it up to 2px.)

    1. That is awesome. Thank you. I wanted to do that, but I did not have the know-how/wherewithal and had to let it go.

      That's the best graphic of the year. Thank you.

  2. No problem. I thought I posted this earlier already but I guess I only hit the preview button. Here's an alternate version that I think I may like a little more.

    1. Thank you; I'll get it up as soon as possible. I have a really slow wi-fi connection right now; good excuse to go back to Starbucks (always a problem when I'm traveling).

      Again, thank you.

    2. The reason it did not download initially, the "jpg" was actually "jpeg."

      Now that I see the new version I wonder about the relative sizes of the circles. The Western Gulf (Eagle Ford) is 1.73 and the Williston Basin is 7.4 (or thereabouts). The ratio is about 4:1. The Williston Basin circle appears significantly larger than 4x the Western Gulf. I may be misinterpreting something, but it just seems larger than 4:1.

    3. The circle for the Williston Basin on the second one has a diameter of 553px. (553*1.73)/7.38 = 129.6, so I gave the Western Gulf a diameter of 130px, and did it that way for the others as well.

    4. Got it, thank you. I've posted that updated version.