Oil companies plan to store millions of barrels of crude at sea as they wait for demand to pick up and prices to rise.
So far oil companies have booked ships capable of holding up to 10 million barrels, brokers have said, more than the daily output of top exporter Saudi Arabia.
On Thursday U.S. oil trader Koch and Royal Dutch Shellwere the latest to confirm bookings of additional Very Large Crude Carriers (VLCC), brokers said.
The companies were not immediately available for comment.
Brokers said the cost of hiring vessels at current depressed rates would be less than the gains from waiting for an upturn in crude prices and in refiners' profit margins.
More oil and trading firms were also considering floating storage, they said.
"If you're looking at it from a cost perspective, just float the oil. The way to make money is to buy long and then go short," one trader said.
U.S. crude CLc1 has fallen more than $90 from its July peak above $147 a barrel as the slowing economy hurts global oil demand.
Some of the vessels were to load crude in the North Sea, the first time large volumes have been placed in floating storage there since the oil price crashed to below $10 a barrel in 1998.
"All this oil has to go somewhere, especially if the refiners aren't running at capacity," a Singapore-based crude oil trader said.
Koch has booked VLCC the Dubai Titan, with capacity to hold over two million barrels, for storage off the U.S. Gulf Coast. They added that Koch had already taken two other VLCCs for storage in the U.S. Gulf.
Oil major Shell has booked a second supertanker to store North Sea crude, ship brokers said.
They said Shell would use the Front Crown to load North Sea crude in the second week of December. The vessel will travel east to Indonesia's Karimun Islands, where oil is often transferred from supertankers to smaller vessels for delivery.
Shell booked another supertanker last week to take two million barrels from the North Sea for storage in the U.S. Gulf.
Although prompt delivery oil is very weak at around $50 a barrel on Thursday CLc1, its lowest level since January 2007. Contracts for March and April next year are above $53.
That has triggered some speculation big oil producers in the Organization of the Petroleum Exporting Countries could also store crude on ships for later sale.
But for Middle Eastern exporters, responsible for the bulk of any OPEC output cut, it is still cheaper to keep the oil in the ground.
"The only reason as a producer you would pay money to put crude in floating storage would be if you would otherwise struggle to get it out of the ground," said one Gulf industry source.