Now if you are a financial participant you need to close out your position as you are not in a position to either deliver/receive physical oil - so you need to essentially pay whatever it takes to close out the contract. In normal times there is plenty of storage and physical participants that are willing to provide liquidity as the contracts come to maturity. Now imagine you are a physical participant, and now space is limited/storage is expensive/ natural buyers aren’t buying (refiners) - you are not going to pay much to buy the oil of a financial participant who needs to sell the May contract to roll into June/July...