Those who will physically deliver the crude are short on their contracts at settlement date.
Because of their massive production, they just can't sell in a single day.
So, those who short the contracts really lose money as price increases.
Yes, I am not an expert but I think producers, if they have to enter the market prior to expiration , get hedged asap( in an other expiration ? ). Producers don't like risk at all.
If you read carefully, you'll see I said oil producer COUNTRIES.
Not companies, countries.
Companies buy oil from countries, and usually resell it to refineries, or sometimes refine it themselves and sell the products to the distributors/consumers.