At that time 2/3 of the US production was from "stripper wells".
Stripper wells produce only a few barrels of oil a day.
It added up though. When the price wen so low they couldn't be kept in production, so they were shut in.
The problem is, once a stripper well is shut in, it cannot be brought back into production. The well has to be re-drilled a short distance away. The cost of re-drilling is too much to ever pay out, so the production is gone forever.
A better policy would have been to have a minimum price paid to stripper wells so they would not have been shut in.
Those involved in the oil patch knew this, but nobody would listen, so it is gone.