2006-08-03 11:43:06 · 23 answers · asked by Anonymous in Science & Mathematics ➔ Earth Sciences & Geology
Sometimes the earth does cave in. It doesn't have to come from oil extraction, dewatering of certain aquifers will cause subsidence.
Natural gas, oil, and water are predonimately found in sandstone. Sometimes they are found in limestone and dolomite, but that is another story. These fluids reside in the pore spaces of the sandstones, the areas in between the sand grains. But, in order for oil and gas to be trapped, the sandstone has to have a some sort of domelike structure or be faulted and the top has to be sealed by a impervious rock like shale. Otherwise the oil and gas will have dissipated or dispursed. At depth, natural "rock pressure" rises. When drilled into, the oil and gas will naturally flow from the higher pressure rocks into the lower pressure well bore. It is then pumped to the surface.
There are a number of enhancement techniques to force the oil into the well bore more quickly, such as enhancing the natural fractures of the sandstone. Another is to pump water, mud, steam, polymers, etc. into a depleted wells that are down structure from the producing well. This will push the residual oil into the production well.
As oil is being produced, the downhole pressure in the sandstone drops, and sometimes it is not enough to sustain the sandstone's integrety and it collapses. This causes subsidence and it can occur over vast areas. The same thing happens with over produced aquifers. The water level drops and the sandstone cannot maintian its structural integrity and it collapses.
This is the short version.
No, oil is NOT be regenerated as we use it. Yes, oil is being generated, but extrememly slowly. Slow enough that we will never see it. Essetionally, what oil we've got is all the oil we got. Once its gone, its gone.
Hope this answers your question.
2006-08-03 13:42:01 · answer #1 · answered by Tom-PG 4 · 0⤊ 0⤋
Sometimes it does cave in. But nowadays prior the extraction, a lot of geographical surveying is done to make sure nothing that detrimental occurs.
Carbon Dioxide Sequestration (where we pump CO2 back in these empty oil pits) also causes geological disturbances and a lot of study is now being done to ensure this can be safely performed as well.
2006-08-03 18:46:24 · answer #2 · answered by ymingy@sbcglobal.net 4 · 0⤊ 0⤋
Sometimes it does, but since they are so deep most of the time even if it did cave in the people above wouldn't notice since it would be a large area where the rocks and soil would come from. They also try to fill the holes when they are done with them to reduce this, but there can be problems in the mean time.
2006-08-03 18:49:07 · answer #3 · answered by Lady 5 · 0⤊ 0⤋
I believe these well run for a very long time, there's nothing they do to fill it up after they are done as far as I know. These things are so deep the ground would not cave in anyhow.
I have a friend that works in natural gas wells and they will last for 50 to 100 years running day and night, I'd assume the same goes for black gold
2006-08-03 18:59:25 · answer #4 · answered by searing 3 · 0⤊ 0⤋
I think they should fill the holes with Nerf. Then if there's enough Nerf in the Earth, Asteroids will just bounce back into space.
Seriously, Just ask any roughneck or mudman at any oil rig. He'll tell you that the oil is forced out by pumping mud and water down there to displace the volume of oil.
2006-08-03 18:57:49 · answer #5 · answered by Tim C 4 · 0⤊ 0⤋
Simply put, oil is found in the sands below the earth's surface. Although the oil is extracted, the sands are still there even after the oil comes out.
2006-08-03 18:47:51 · answer #6 · answered by bradlandreth 3 · 0⤊ 0⤋
Oil is extracted from Sands and limestone. General cavity if they exist are small. and over burden caps are of much stronger strata layer to stop any collapse from occuring (or permiating to the surface without a drill)
2006-08-04 14:30:55 · answer #7 · answered by Anonymous · 0⤊ 0⤋
New oil is continually made.Water flows in to the cavern and new oil is produced.It's heat--high pressure--radioactive and granite coal.Because of these unique conditions there could be a replicating phenomena that takes place.You pump off oil but the reservoir remains full.
2006-08-03 19:11:00 · answer #8 · answered by Balthor 5 · 0⤊ 0⤋
The oil is not in a "Hole" but is in porous rock, similar to a sponge......it is forced out by pumping down a heavier solution which is called "Mud" and is mixed according to the depth and density (roughly speaking) of the oil/gas
2006-08-03 18:45:55 · answer #9 · answered by BackMan 4 · 0⤊ 0⤋
Yes my answer is the same as the first answer. But this may be about to change due to a new project called the hydrogen carbon power project.
2006-08-03 18:51:29 · answer #10 · answered by wildwind 2 · 0⤊ 0⤋