As a non-expert, abandoned oil wells appear to me to be perfect solution for ever growing amount of plastic waste we are generating every year.

These underground pockets held crude oil for millions of years without allowing it to seep into the surrounding soil or the water bed.

Why can't we grind down the plastic waste and deposit it into these pockets where it will be mixed with the remaining crude oil and will have millions of years to decompose?

I'd love to hear why this is either not technically possible, not feasible or not really a good solution for this problem.

  • $\begingroup$ So what about the microscopic plastic particles getting where they should not? like the oceans and fish... What else do you think you could consider/ $\endgroup$
    – Solar Mike
    Commented Jul 21, 2023 at 17:25
  • $\begingroup$ @SolarMike How would microscopic plastic particles get into oceans and fish from oil wells hundreds of miles away from any body of water? The same oil wells that held crude oil for millions of years without leaking it... $\endgroup$
    – Dean Kuga
    Commented Jul 21, 2023 at 17:37
  • $\begingroup$ You need to re-read... "getting where they should not?" the oceans were an example... and nature can let things escape, ever heard of volcanoes or earthquakes? $\endgroup$
    – Solar Mike
    Commented Jul 21, 2023 at 17:42
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    $\begingroup$ One could not get permits. The oil companies are not even allowed to put the water that came out with the oil, back down the wells in some fields. And the formations are essentially solid rock with some cracks. $\endgroup$ Commented Jul 21, 2023 at 18:30
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    $\begingroup$ How do you intend to keep that plastic fluid? If you are expending energy to grind or melt, you might as well turn the plastic into something else like blocks to build homes. $\endgroup$
    – Abel
    Commented Jul 22, 2023 at 11:48

2 Answers 2


On the technical side, there are a number of issues. Each site will have unique issues in terms of length of the return "duct", overall gradient and gradient changes along the "duct". Another one will be temperature along the returning "duct" and at the deposition site. The grind size and particle distribution will be another. Ensuring the plastic "emulsion" remains thoroughly mixed is another and getting the rheology of the plastic emulsion will require research.

Then there are issues with how the plastic solids would deposit in the disused well and whether they would simply block the pores near the well site preventing further deposition in the former reservoir. This also begs the question, what do you think the structure of an oil or gas reservoir is? It's not a large underground void that has been filled with oil or gas, it's the pore spaces between grains and sand and other minerals in a porous sedimentary rock which collected oil and/or gas. Getting ground plastic into such tiny pore spaces may be impossible to achieve, even if the ground has been fracted.

On the operations side of things, oil companies would resist being involved with such as system because they would prefer fewer commitments and not to be burdened with the cost of such a system despite their position on a social license to operate.

Additionally, the oil and gas industry hasn't had great success returning carbon dioxide from methane gas wells back into oil and gas reservoirs.


As oil is sucked out of the pocket, the pocket collapses and the soil above it slumps down and subsides. So once the pocket is pumped to empty, the pocket itself is gone.

This effect is strong enough in some oil fields to cause roads in the vicinity to crack and sink.


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