Movement of Gas from High Pressure to Low Pressure

[Benjamin8998]

Hello All,

 

I was wondering if you would like to take a shot at these questions that I am yet to find correct answers for. In the Figure attached you will see that there is Methane Gas just under Ocean Bed 30,000 feet below the ground level. Pipe A is a hollow pipe drilled to the Ocean Bed with just natural air in it to let Methane Gas exit. Pipe B is filled with water with a small methane gas outlet drilled in to the pipe separately.

 

My Questions:

 

1) Will gas come out by itself from Pipe A due extreme pressure at ocean floor because of surrounding water above and decreasing pressure as we go up to ground level through pipe? If it will come up by itself what are some theory/formulas that could be used to find the velocity with which the gas would travel out?

 

2) Because I have noticed that if Scuba Diver exhales or let some oxygen pass through water, it quicky rises up to the surface level due to difference in densities. Would it be better to have a pipe like Pipe B filled with liquid such as water for the gas to go up faster than it would in hollow pipe? What would be some theory/formula used in this case?

 

Please feel free to ask questions that you believe are necessary assumptions to answer any of the above queries.

 

Thanks to you all for your time and support.

 

Best,

 

Ben Saini

Pipe_Diagram.pdf

[Newbies_Kid]

Are you really sure the methane is in the gas form? because I only heard about solid hydrate of methane buried under the ocean bed.

[Ophiolite]

Ben,

please keep your questions on this topic to one thread. If you want to post other clarifications put them into that thread. Perhaps a kind moderator will merge the two threads.

 

You are looking for a simple answer to a complex subject. There are screeds of publications on production technology and quite bit of recent research on clathrate development, though not much of that is published. Can you be more precise as to why you are asking and. that will make it easier to pitch the answer appropriately, or to point you in the right direction.

[Benjamin8998]

Absolutely, the reason why I am asking this problem has less to do if we can find methane in gas form, but its more of if one finds a gas that far down in ocean what would be the best way to bring it upto ground level. I just took example of methane gas as I thought it would make the problem more realistic.

 

My query is simple: the pressure difference on the pipe between ground level and 27000ft is a big number, can one rely on just this pressure difference for the gas(any gas) to go to ground level by itself? or would one have to use suction equipments. If we can rely on pressure difference for gas movement what are some possible ways to predict the volumetric speed of gas at the end of the pipe above the ocean.

 

I will keep my future questions on one page in the future.

 

Thank you all for your for your valuable time and wisdom. I look forward to hearing from you.

 

Best,

[Newbies_Kid]

so there must be a layer which can separate the gas from the sea water right? then if you able to penetrate the layer with your pipe the gas surely will go up for himself. But i still don't understand how a gas can be trapped on ocean floor..

[Benjamin8998]

Hi Newbies_Kid,

 

thanks for your reply. I understand that its not possible to have gas at that high pressures and low temperature, but I just wanted know if we do find gas at there what would be the best way to bring it up 1) a hollow pipe or 2) on filled with some liquid like water ?

 

Look forward to your reply.

 

Ben

[Newbies_Kid]

hurmm... so i just assume the gas trapped in a membrane-like layer to make it looks possible. So i think i will use a hollow pipe because if you use pipe B, there will be a burst of water bubbles coming out at the top outlet of the pipe. Considering the high pressure from bottom, i'm afraid the water burst can flung nearby things up high. In 30000ft depth or less equal to 10000m (am i right?) the pressure applied against the gas is about 100000kpa (every 1 metre depth the pressure increase for 10kpa). So use the formula P = F/A, we can find the rising force of the gas if you know the cross section area of the pipe. Assume the pipe area is 1m^2, so the exit force will be 100,000 N. Then use equation F = Ma, we can calculate the speed/time (acceleration of the gas). The mass of the gas will be so small and this means it will go up very fast. To calculate the velocity, you can use the kinematics equation of V^2 = U^2 + 2a (r - r0). Initial velocity = 0, and we have the velocity.