Question: conventional wells or unconventional wells -- which have a
higher ratio of produced water, conventional wells or unconventional
wells? What is the ratio of produced water-to-oil in conventional wells
compared to that of unconventional wells? [PWOR = produced water-to-oil
water.]
The answer will be posted Monday, August 4, 2019, sometime during the
day after I get caught up with the news that came out over the weekend.
Originally posted here, so some answers/replies will be at that post.
On another note, 99.9999999%+ Americans can be thankful they had an
uneventful weekend. Huge condolences to the families in Dayton, OH, and
El Paso, TX.
Answer: conventional wells. And it's not even a close call. [
Later, see this post also.]
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Best Answer From A Reader
Your question regarding produced water is significant for several reasons.
Conventional, vertical production may have
90 to 99 barrels of water for every single barrel of oil produced as a routine matter for older wells.
This is the single biggest expense in low producers and is
the main determinant of when to permanently plug a well.
Unconventional in the Bakken is frequently in the
1 bbl water /1 bbl oil range which is
pretty remarkable and a huge influence on the long term positive economic potential.
Water handling (for frac'ing in LTO, disposal in conventional and unconventional) is a big component in oil development operations.
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Source From The Literature
This is what caught my attention and why I asked the question.
This is a screenshot of the abstract from an article published in 2017 with regard to the Permian.
The third sentence in that abstract: our results show that although
conventional wells produce about 13 times more water than oil ... [a]lthough unconventional wells have a much lower PWOR of 3 versus 13 from conventional wells ...
This is the link to that article:
https://pubs.acs.org/doi/10.1021/acs.est.7b02185. At the link you can download the pdf.
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Produced Water Vs Flowback
A reader asked the question: what is the difference, if there is a difference, between produced water and flowback. The reader who best answered the original question, also provided this answer regarding produced water and flowback:
On whether flowback is same as produced water?
It is not, but I can not offer any legally/technically precise definition with which to precisely distinguish one from the other.
In the early Bakken years (probably Eagle Ford and Niobrara also), huge amounts of the frac fluid would be somewhat rapidly - within a few days' time - removed from the newly frac'd well.
This was partially motivated in not wanting the formation to absorb the water, swell and inhibit production.
In the last 2 to 3 years, it is obvious that operators are maintaining VERY high quantities of frac water underground for SEVERAL months and the now-surfacing water is labelled as flowback.
(The earlier years' rapid flowback was - to my knowledge - never officially recorded).
This is why when the recent wells' production profiles show 200,000/250,000 barrels produced water first 5 months, purposeful underground retention is indicated.
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For me, I apologize to readers. To some extent this was a "trick question." Everyone writing about fracking, including me, writes about the huge amount of water being used to frack the wells. So I was quite surprised to see how much water is actually used in conventional wells.
For me this was incredibly important: with the recent discussion of porosity and permeability, there were sidebar issues regarding water. If oil producers seem hassled by natural gas / flaring, I would imagine that issue pales in comparison to the problem they have with water.
Along with everything else about water in that linked PWOR study, there was a footnote in one of the replies to the porosity / permeability issue with regard to how Saudi Arabia almost "lost"one of their best fields due to water channeling.
So, I apologize for the trick question, but, wow, I sure learned a lot.
