[wolfman]

I didn’t realize that the hydrates got that cold. I guess I was under the impression that oil that deep in the earth was very hot due to thermal heating.

[Cold Heat]

No, the well is in a reserve that is deep but not that deep for it to be hot. The natural gas at that depth is in liquid form. As it rises up the drill pipe and pressure begins to drop, it turns into a gas and expands. The higher it goes the more it expands and this expansion requires energy which it takes from anything that has it so it is like freon.....very cold when it changes form. It then combines with the sea water as it exits the pipe and forms a slush which they call hydrate. It is also this expanding gas that causes the oil to billow out like it was being pushed. It is being pushed.

[Cheesehead In Dubai]

Hydrates occur when the highly pressurized gas from the well-bore takes a pressure drop (expands). From high school chemistry you should know that expanding gas cools. When the methane gas encounters water (either entrained water from the well fluids or sea water) the mixture will freeze. To prevent hydrates from forming you have to either heat it up above hydrate formation temperature, equalize the pressure to prevent the sudden expansion or add methanol to alter the composition of the methane (gas) water mix.

[jpsb]

"The temperature is always increasing with depth, but it increases at a different rate depending on the layer of the Earth. So, in the upper part of the Earth’s crust, the temperature is increasing at about 25 degrees Celsius per kilometer (or 72 degrees Fahrenheit per mile)"

The oil is about 2 miles down (3 if you count the sea) so oil temp would be approx 140-150F.