Methan Gas Under Ocean

[Benjamin8998]

If there is natural gas found say 20,000ft under ocean just below ocean floor, can we just drill a pipe and expect gas to come up due to immense pressure 20000ft below or do we have to put a pump to suck the gas out to ground level?

 

also please suggest best way to do the same most efficiently and economically.

 

Thank you

[Ophiolite]

Since the gas reservoir in your example will be penetrated by a cased borehole the external hydrostatic pressure of ocean water and pore fluids does not have to be overcome. Once production is underway the only constraining pressure on the formation fluid is that of the column of gas and any associated fluids within the production string. The issue is then one of 'choking' back on the flow to prevent an uncontrolled release of the gas. In a depleted oil reservoir pumps may be installed in the well to maintain the flow. Alternatively or additionally gas or water may be injected in adjacent wells to sweep the reservoir free of remaining hydrocarbons. (Note that at best we recover only 50% of the oil in a reservoir, usually less.)

[Benjamin8998]

I have taken another shot to better explain my last question would you please take a look at my new post.

 

http://www.scienceforums.net/topic/52880-movement-of-gas-from-high-pressure-to-low-pressure/

 

Look forward to hearing from you.

 

Best,

 

Ben Saini

 

Since the gas reservoir in your example will be penetrated by a cased borehole the external hydrostatic pressure of ocean water and pore fluids does not have to be overcome. Once production is underway the only constraining pressure on the formation fluid is that of the column of gas and any associated fluids within the production string. The issue is then one of 'choking' back on the flow to prevent an uncontrolled release of the gas. In a depleted oil reservoir pumps may be installed in the well to maintain the flow. Alternatively or additionally gas or water may be injected in adjacent wells to sweep the reservoir free of remaining hydrocarbons. (Note that at best we recover only 50% of the oil in a reservoir, usually less.)

[Newbies_Kid]

Did you ever heard about methane hydrate?

Methane hydrate

 

Due to rapid global warming, scientists were afraid that enormous amount of methane will be released into atmosphere and contribute to more rapid heating. Several O&G companies like Conoco Phillips are currently found some big reservoir of methane hydrate in Alaska but i don't sure if they already can take the methane out or not. Last year i read an article that they had a problem if too much methane are taking out because it will cause the base of the reservoir become unstable. So they plan to inject a same volume of CO2 to replace the volume of methane. If the plan succeed, we can reduce our global warming in big percentage

[TonyMcC]

Some people think that some sudden sinking of ships in the Bermuda Triangle may be due to a huge release of methane hydrate from the sea bed. The bubbles would reduce the density of the sea water making the ships sink. Whether this is true or not, released gas would certainly bubble its way to the surface.

[Rhiaden]

If I remember, the methane is stored in Methane Clathrates under the ocean floor, these are very unstable, and sensitive to temperature and pressure.

 

One of the issues with extracting these methane resources is that once they are brought up to a warmer temperature with lower pressure, the gas has a tendency to expand rapidly.

In the confined space of a pipe, this is potentially explosive (There are videos out and about showing this).

 

The methane clathrates stored under the ocean floor are one of the uncertainties in climate feedback. The temperature at which these clathrates become unstable is still unknown, and the quantity is also an unknown. Largely it exists in a region known as the Gas Hydrate Stability Zone. This is sediment where the temperature is cold enough to keep the methane within the clathrate structure. This zone is relatively shallow, in that it only extends a few hundred meters below the ocean floor.

 

Along with the bermuda triangle, Methane is also suspected as the cause of ocean floor collapses, including one off the coast of Norway several millenia ago.

[mississippichem]

Thought this might shed some light:

 

 

Looks like this stuff goes away pretty quickly at STP.

[Newbies_Kid]

yep, methane hydrate only formed under high pressure + low temperature.. not only on ocean floor, it could also formed under frozen lake. So be careful when you smoking while walking on those frozen lake ^^,. Usually they used to store those burning ice in liquid nitrogen to preserve its form. But i really don't understand how methane hydrate cause the airships disappear at Bermuda triangle??

[Benjamin8998]

But would you all agree that the high pressure on the pipe due to water above and surrounding will add to the gas movement towards the surface. And that pressure would help any gas for that matter to move up from high pressure zone to low pressure zone ?

 

What could be some theory/equations I could use to calculate rate of change of volume and velocity with which a gas would travel from high pressure zone 30000ft below to 1atm pressure at ground level.

 

Thank you all for your contribution.

 

Ben

[johnmarsh]

nice information thanks for sharing this

[dragonstar57]

One of the issues with extracting these methane resources is that once they are brought up to a warmer temperature with lower pressure, the gas has a tendency to expand rapidly.

In the confined space of a pipe, this is potentially explosive (There are videos out and about showing this)

then shape the pipe like a funnel.

the pipe expands as the gas expands.

[Dune]

yep, methane hydrate only formed under high pressure + low temperature.. not only on ocean floor, it could also formed under frozen lake. So be careful when you smoking while walking on those frozen lake ^^,. Usually they used to store those burning ice in liquid nitrogen to preserve its form. But i really don't understand how methane hydrate cause the airships disappear at Bermuda triangle??

 

The theory is that methane bursts from the surface of the ocean, and being lighter than air, floats into the atmosphere. A plane flying through a cloud of methane stalls due to lack of oxygen, needed for combustion in the propulsion system.

[TonyMcC]

Some people think that some sudden sinking of ships in the Bermuda Triangle may be due to a huge release of methane hydrate from the sea bed. The bubbles would reduce the density of the sea water making the ships sink. Whether this is true or not, released gas would certainly bubble its way to the surface.

I said some people think that a huge release of methane hydarate from the sea bed could result in SHIPS sinking. I don't know who has suggested it could cause AIRSHIPS to disappear!

[Dune]

I said some people think that a huge release of methane hydarate from the sea bed could result in SHIPS sinking. I don't know who has suggested it could cause AIRSHIPS to disappear!

 

Umm, the guy in post 8 above. Along with about 4730 google responses http://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4ACAW_en___US399&q=methane+causes+planes+to+crash+bermuda+triangle

[TonyMcC]

Umm, the guy in post 8 above. Along with about 4730 google responses http://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4ACAW_en___US399&q=methane+causes+planes+to+crash+bermuda+triangle

I thought the guy in post 8 was referring to my earlier post. I would not be surprised if airships had disappeared, however a quick scan on google only provided me with tales of the "ghost blimp". This particular airship didn't actually disappear without trace - only the crew.

 

yep, methane hydrate only formed under high pressure + low temperature.. not only on ocean floor, it could also formed under frozen lake. So be careful when you smoking while walking on those frozen lake ^^,. Usually they used to store those burning ice in liquid nitrogen to preserve its form. But i really don't understand how methane hydrate cause the airships disappear at Bermuda triangle??

Hi Newbies_Kid,

Where did you get the information regarding disappearing airships?

[Hearts]

 

Hi Newbies_Kid,

Where did you get the information regarding disappearing airships?

 

 

Actually I think he meant ships( that travel on water). The term (air)plane is more commonly used nowadays (at least, in my environment)~

I did hear about disappearing planes~ which disappear without even trying to radio for help...spooky

Anyway~ back to topic please.

@dragonstar: Shaping the pipe like a funnel sounds a lil impratical to me. Are there people already doing this?

Edited February 24, 2011 by Hearts