Well it was my hope someone here already knew, since it is not a trivial search criteria.
But I found it anyway.
{...
From the destination ports they will be sent to distributors, trucks and finally delivered to fuel stations. So, in the best case, it takes about 2 weeks from the well to the station. On the worst about a month, give or take a week.
...}
So then it is even shorter than I thought, with it being only 2 weeks instead of the 4 weeks I allowed for.
Which means the covid surplus can not possibly now be the cause of any shortages or high prices any more.