From: Cape Canaveral, Florida
I've seen the same thing. For some reason, you can not load oil in LA that would leave it with less than 25,000.
Furthermore, as far as I can find, LA produces 20,000 oil per day and that is the only oil production in North America.
And - according to Tracker LA uses 25,000 oil per day.
Despite these contradictions, I never see production in North America failing. I do see it fail for lack of oil in Australia and Pearl Harbor. (BTW, PH also wants for resources that must be shipped in, and Australia needs to have fuel supplied too.)
I don't know the answer.
In WITP I remembered you needed to ship a few tankers once a month to Australia/Sydney with oil, and after Java fell I ran out of free oil to steal. Wasn't sure if I needed to supply Sydney with oil or fuel.