OK, let me preface this by stating that this question resulted as an argument my wife and I had recently.
Wifey contends that we are risking implosion or some type of catastrophic event due to expanding our oil exploration. She compared the Earth to an orange, and oil wells as straws that “suck all the juice” out of the Earth, thereby causing the orange (Earth) to shrivel and implode.
:rolleyes:
I tried to calmly explain that the Earth is very unlike an orange in it’s internal composition, the crust, the mantle, the core, etc and that what she describes is impossible. She got so upset with me “proving her wrong” that she withheld sex from me for the night…which I am accustomed to anyhow!
Anyway, my question is this: Is there any merit to the idea that oil exploration can trigger a seismic event of some kind? Is it possible that we can inadvertently create fissures in the crust of the Earth with these deep-drilling oil rigs, or is the crust uniformly sufficiently thick to withstand having so many holes poked in it?
I think she has a very, very serious comprehension problem about the total size of the earth as a sphere versus how far we are able to drill into. Soviets gave it their best to dig the deepest hole in the world. The Kola Superdeep Borehole was the result and, while extremely impressive, it is still only about 7.6 miles deep and didn’t come close to penetrating the crust itself. In comparison, the diameter of the earth is about 8000 miles depending on where you measure. There is no known way to dig any deeper than that. The earth becomes very plastic a tiny fraction of the way down. Trillions of barrels of oil sounds impressive until see how that stacks up against the size of the environment that it is all coming from.
Petroleum Geologist here. There’s little chance or evidence of something happening on the scale that’s driving her concern. In the first place, usually oil is extracted from the porous spaces within rock through permeable pathways. The structure and integrity however remain intact. Secondly, many oil fields have a water drive system. Once the oil’s been recovered, the void it once occupied is quickly replaced by water.
Of course this is a very simplified explanation and doesn’t accout for every conceivable scenario. Some settling does occur in places, much like what would occur given additional overburden. But your wife can rest easy. We’re not approaching a scenario from our production successes that has created some impending worldwide, caldera-like disintegration. Field maturation just doesn’t work that way, nor would it have that much of an effect on continent-wide crustal stability.
Thanks for saying that about her, because I’m not allowed to!
Anyway, thanks also for the scoop on the Russian hole in the ground. I didn’t know what our capability was in terms of exactly how deep we could drill.
FTR, I never thought that the Earth would or even could implode, I was more wondering aloud if it was possible to trigger a quake in a localized area or some such minor disaster.
One billion barrels of oil (55 billion gallons) takes up 7.39 X10^9 cubic feet.
That’s equal to a cube 1,944 feet on a side.
World oil production of about 90 million barrels per day represents 32.9 billion barrels a year.
That’s equal in volume to a cube 6,232 feet on a side.
Ah, don’t you love the female “I said something batshit insane, you proved me wrong, so I’m going to punish you by withholding intimacy” behavioral pattern? :rolleyes:
Like Shagnasty said, most people just don’t get how large things are and cannot comprehend the size differences and distances.
To be sure, there will eventually* be some settling or ground compression due to large scale oil drilling, coal mining and other mineral removal, but it’s going to be localized and the entire Earth is in no danger of imploding or being destroyed by it.
Maybe tomorrow if a major earthquake hits that area and all the mine shafts collapse, maybe over the course of a million years as the ground slowly compresses into those empty spaces.
For oil removal in coastal areas, it would seem that salt water infiltration is more likely to be a problem, like in coastal areas in which too much water is being pumped from the ground.
Total volume of oil ever pumped is 1.08 trillion barrels. I’ll leave the math to someone else, but it is a vanishgly small percentage of the volume of the Earth.
There’s also asphalt bubbling up out of the ground in L.A., so I wonder how deep those wells are.
Anyway, I wanted to point out that it is impossible for the Earth to implode. Gravity already pulls the earth together as tightly as possible, and the inner parts of the planet are largely fluid. The continental plates float on top because they are made of less dense material. It would take an enormous external crushing force to make the Earth any smaller than it is now.
An orange is about 10 centimeters in diameter (5 cm to the center). The rind and the pith together are about 6mm thick, and is full of pockmarks (probably about 1 millimeter deep). The rind, therefore, is about 12% of the distance to the center of the orange (6 mm out of 50 mm). The deepest pockmarks are barely 2% or the depth, and they don’t affect the orange at all.
The earth, by comparison, is about 12600km in diameter (6300 km to the center). The crust is a mere 30 km deep, on average (about 0.4%), which means the rind of an orange is proportionately 35 times thicker than the Earth’s crust.
But don’t tell her to panic. The Earth isn’t about to fall apart. The deepest hole we’ve dug is only 12 km deep, or about 0.1% of the way to the center.
In other words, each of the hundreds of pockmarks on an orange are proportionately 20 times deeper (on an orange) than the deepest hole ever dug (on the Earth). Oranges don’t fall apart from the pockmarks, so she can cease fretting about the earth being pierced by oil wells.
(Never mind the fact that the Earth is held together by gravity, and all that.)
The easy ones of the past were the first to be exploited. Oil tries to migrate upward, so anticlines and salt domes were some of the first surface structures prospectors searched out.
The evolution of exploration since though has had to consider a dizzying multitude of possibilities. Structure and trapping mechanisms don’t insure success. You’ve got to identify a source, a seal, proper thermal window, subsequent migration, etc. Even with seismic, many things above it, salt for example, can cloud the picture and even then seismic’s only an indirect indicator. Just trying to sink pipe to your target is fraught with hardships, everything from dangerous, undected shallow gas that may cause a blow-out to scorching heat downhole to caverns that’ll drain all your mud to finding reservoirs that are impermeable or simply non-productive.
We’ve got some great tools and certainly understand more than we used to but it remains, and always will be, a very uncertain proposition.
Ooh, well done. Very clear explanation using the original scenario. Unless the wife in question truly is batshit insane, this should make her feel better.
