Thursday, January 14, 2016

Overburden Pressure for Scientifically Confused Dummies

Density tool sonde (Schlumberger)
If you are looking for a simple, reasonable explanation of an unfamiliar concept that is somewhat esoteric, you don't go to eHow.com in your search. If you need a solution to a highly technical problem, you aren't going to find it anywhere at Leaf Group, including their flagship of all misinformation, eHow. That doesn't mean someone on their crack(ed) staff of freelancers hasn't tried to answer your question at one time or another; in fact, it's a safe bet that someone with absolutely no background in the subject has done precisely that. Someone like Darby Stevenson, who parlayed a double BA in religion and international studies into an article that allegedly explains "How to Calculate Overburden Pressure" at CareerTrend.com (another  Leaf Group niche site). To say his reply is half-assed is an insult to half-assed answers everywhere...

Darby more or less gets the definition right in his introduction:
"Overburden pressure is the vertical pressure applied on a layer of rock from the rock and soil above it..."
...though that overemphasizes the importance of soil and ignores the possibility of a column of water (such as might be present in an offshore oil well). Darby then explains -- sort of -- the same thing that's covered in far more detail by the oil industry's go-to website, Crain's Petrophysical Handbook, which Darby attempted to use in his answer (you know he knows it's an oil industry "thing" because he used an image of a pumpjack). Here are a few passages that make it crystal clear that Darby knows jack about the subject at hand...

  1. "Take a density log reading of the area you are measuring..."  – "[O]f the area," you say? No! you're measuring a vertical column from a subsurface point, Darby, not an "area." Besides, a reading is a single point on the log – you want to run a log from the surface to the depth of interest. Idiot. 
  2. "The area to be measured will need to be dug out to create a well bore through to the lowest layer of rock to be measured..."  – It's called a well, Darby, and you don't "dig" it, you drill it – in fact, it's already drilled! Sheesh!
  3. "The engineers taking the density log measurement will emit gamma rays into the bore..." – I sure as hell would not want to share an office with an engineer who emits gamma rays, sir!
  4. "...density [is] expressed as kilograms per cube meter..." – Only someone with a double BA would talk about "cube meters."
   
       Once again, eHow's crack researchers demonstrate a total lack of knowledge while misinforming any poor fool who happens along while looking for an answer to a knotty problem. Small wonder the site regularly provides the Antisocial Network's Dumbass of the Day –about 75% of the time, in fact...
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