It's not going to go very low, I don't think. Even if the storage pressure lasts ( it may not... )
The profit for the movers part is driven by who's got how much storage and where. The zero prices are being driven by some of the large middlemen forcing the smaller vendors who are storing in tankers at sea and trains and trucks etc. These sort of things cause load shed and back pressure problems. It's cheaper to deliver the thing than have it sitting in the tank losing value by the second.
Again, this is posturing and all sorts of complex moving parts that atleast I don't have insight into.
A school mate of mine is the captain on one of these super tankers, sitting parked off the coast in Singapore. Full of oil no one wants, not the vendor who loaded it, and nor the refinery they were meant to deliver to. Crew is being paid by insurance money.