How long does it take for oil to burn itself out?

I am writing a book in which the main character sets fire to oil floating on the surface of a swamp so his enemies won't be able to follow him through it. Without too much use of artistic lisence, how much time can this buy him before it goes out?How long does it take for oil to burn itself out?
It will depend on the type and the amount. First, putting what most people call ';oil'; on a swamp would be very difficult and would be very hard to ignite. It will not spread well and you will need a blow torch to lite it. Gasoline spreads better and lites easier, but will burn out pretty quickly. It may spread so thin that it would ';poof and be gone';. To use oil, you need to mix it with something like gasoline to get it started.





A better choice would be napalm or kerosene or a mixture of the two. Napalm would be harder to spread if you didn't have a sprayer. Kerosene would spread well and stay lit for at least a short while. THe next problem is the amount. 55 gallons of kerosene is not going to burn over a very big area, may 5-10 minutes (unless it also spreads to trees). It would hold the bad guys out long. A better idea would be a 250 gallon tank on the back of a swamp boat the you moved across the swamp to spread it out. You could use napalm in that case.





Of course, all this information is for a piece of fiction writing. it should nver be used for any other purpose.