[Tallguy]

At 19000 ft oil/fuel turns to sludge. It doesn’t flow.

[Uncle Chip]

So then if it oozed out of an engine on the ocean floor, would balls of sludge float to the surface where it could warm up and morph into an oil slick???

[nascarnation]

At 19000 ft oil/fuel turns to sludge. It doesn’t flow.

Don't understand your comment. Pressure at that level is approx 1000 bar. Most modern diesel fuel injections systems ("common rail") are running at about that pressure.

http://en.wikipedia.org/wiki/Common_rail