Very simple but then the 1000s of news channels pumping out entertainment sorry I mean detailed coverage and analysis don't really want to focus on this rather simple and boring issue.
To explain-oil is NOT meant to stay in the ground once it is tapped. It needs to move out.
If it doesn't then it congeals and can cause huge damage to oil fields.
Can take weeks/months/years to fix, costs a lot of money to repair (if you can even manage to do so) plus in terms of the lost revenue in this period.
And as an extra bonus you won't regain the same capacity that you had before.
Older oil fields are more susceptible to damage. Iran has largely older oil fields.
Countries I.e. Iran do have storage but not huge amounts. It comes out of the ground and it is exported-that's the model. You can cut back on production a bit but not by too much.
So in terms of the blockade the ONLY thing that matters (awful I know) is whether Iran is able to get the oil out/ how fast it is using up the storage that it has.
If they are at capacity then they will fold.
If they are somehow managing to export enough oil to stop their storage capacity from being maxed out fast then they won't
Everything else is just noise.
Oh and no one really knows how much time they have left r.e. capacity.
I would assume the US govt has an idea but who knows. You can use satellites to calculate how low ships are sitting in the water using the shadows they cast but that is the more widely available analysis. Doesn't tell us plebs how much, if any, oil Iran is exporting.
So toss a coin!