[QUOTE=Fear Itself]
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.
[/QUOTE]
It’s 2.05 x 10[sup]-10[/sup].
Thanks, emilyforce. There’s some fudge factor in there, since I’m not sitting here measuring an actual orange… and if I rounded properly, the 12 km hole would be about 0.19% of the distance to the center of the earth — a tenth, not a twentieth, of the depth of an orange pock. Nevertheless, it’s a comforting fudge. 
[QUOTE=FoieGrasIsEvil]
Is that really a functioning oil well, or an unused one in it’s Sunday dress?
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Functioning. It’s right next door to Beverly Hill High School and Century City. Very classy digs for an oil well, hence the pretty wrapper. (For* Die Hard* fans … it’s also a couple of blocks away from Nakatomi Plaza … .)
Part of the reason the L.A. subway doesn’t run to the ocean is that there are big asphalt and natural gas deposits under the Miracle Mile – resulting in the La Brea Tar Pits. When they were digging the Red Line in the 1980’s they accidentally tapped into a pocket of gas and blew up a Ross Dress For Less store. So the Red Line ends its westward journey in Hollywood. Supposedly new tunneling technology will allow subway construction to resume soon.
So, yes, people still drill for oil and dig big tunnels right next door to active faults.
[QUOTE=Pochacco]
.
So, yes, people still drill for oil and dig big tunnels right next door to active faults.
[/QUOTE]
They also drill some wells (2KM or so) very clse to the faults and install permanent pressure gagues and and also hydrophones for doing something called vertical seismic profiling (VSP) . The purpose of which is to monitor stress buildup and changes in the rock properties around the well in an attempt to understand and predict earthquakes.
On the subject of pretty drilling rigs, google THUMS to see the 4 artificial island offshore Long Beach with the well disguised drilling rigs (each island named after the first four US astronaughts to die in active service in the US, how is that for a pointless trivia item for the day.)
[QUOTE=WF Tomba]
It’s 2.05 x 10[sup]-10[/sup].
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Oh, and this fraction of the volume of Fish’s orange would come to 0.107 nanoliters. I don’t know of anything that’s that size, but it’s a very small thing.
[QUOTE=lieu]
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.
[/QUOTE]
I guess my question could be better phrased as “What surface clues give you a reason to even attempt seismic locating in the first place?” (I know you mention salt domes and anticlines…are there any others?)
I’ve often wondered that, especially about a surface like the ocean floor that can be quite uniform. Sand over here, oil, sand over there, no oil.
And what type of equipment (and with what success rate) is used to determine the actual amount of crude is in a given deposit, assuming you find some where you’re looking?
Well, a grain of sand is 1/16 of a millimeter in diamater, right? How many nanoliters is that?
[QUOTE=Pochacco]
Functioning. It’s right next door to Beverly Hill High School and Century City. Very classy digs for an oil well, hence the pretty wrapper. (For* Die Hard* fans … it’s also a couple of blocks away from Nakatomi Plaza … .)
Part of the reason the L.A. subway doesn’t run to the ocean is that there are big asphalt and natural gas deposits under the Miracle Mile – resulting in the La Brea Tar Pits. When they were digging the Red Line in the 1980’s they accidentally tapped into a pocket of gas and blew up a Ross Dress For Less store. So the Red Line ends its westward journey in Hollywood. Supposedly new tunneling technology will allow subway construction to resume soon.
So, yes, people still drill for oil and dig big tunnels right next door to active faults.
[/QUOTE]
Huh. I always had this image of oil wells pumping away in fields in rural areas, like I saw many of when I lived in Texas.
Interesting story about the subway, too.
Thanks.
[QUOTE=Fish]
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.)
[/QUOTE]
I kinda feel bad that you went through the trouble of making those calculations, thank you!
Unless of course you’re a mathmetician and it took you three seconds… 
[QUOTE=FoieGrasIsEvil]
Huh. I always had this image of oil wells pumping away in fields in rural areas, like I saw many of when I lived in Texas.
Interesting story about the subway, too.
Thanks.
[/QUOTE]
Something to bear in mind is the big tall object is a drilling derrick, which is used in constructing the well. Once the well is drilled this moves on to another well. You really would not know a well is there as the only indication would be a small well head and some pipes etc, fairly low profile stuff. The exception to this is if the well under artifcial lift (the formation pressure is insufficient to drive oil to surface) this is where you may see the nodding donkeys aka pump jacks you probably saw in Texas.
Surface geology and the relationship to what goes on under the ground, I could not tell you, no doubt Lieu or Tapioca Dextrin may be back with an answer. Off shore where there is not a lot of correlation between surface geology and subsurface topography, you rely on gravimetric surveys (measure the broad area gravity field in the earth which indicates sedimentary basins) electromagnetic ariel surveys which look at thr resistivity of the rocks which may indicate hydrocarbons in the area, then shoot seismic (basicaly interpeting sound wave echos)
The current 3D seimic can give a very good idea of the shape and size of the various rck layers under the ground. Have a look here and see the little presentation that runs for an idea of the sort of data that is looked at. it is quite pretty,
http://www.pdgm.com/seismic-imaging/solutions.aspx
Look here at the structural interpretation link,
http://www.pdgm.com/structural-interpretation/solutions.aspx
You can als get an idea of what is in the rock, Gas shows up rather well. Time lapse seismic surveys (repeating the same survey over several years) can show movemnst in gas cpas in the reservoir and fluid level changes.
Once structures are identifed the next stage is to drill a hole in the ground, through the reservoir and lower some senstitive measuring devices into the ground which take measurments of the reservior rock, ths is called wireline logging. The measurments tell you exactly how thick the reservior is, how porus the rock is and what percentage of the pore space is filled with oil water and gas.
Once you know how thick the reservoir is and the percenatge of oil, and the area extent from the sesimic you can make a calculation as to the total oil in place.
The company will certainly drill more wells in a field, know as delineation or apprasial wells) to discover the true extent of the reservoir, gather more data (seismic is good but not good enoug for the detailed calculations needed ), understand the flow regim in the reservior and a bunch of other useful info.
It is quite possible to spend epic ammounts of money understanding a reservoir before producing a drop.
[QUOTE=FoieGrasIsEvil]
I guess my question could be better phrased as “What surface clues give you a reason to even attempt seismic locating in the first place?” (I know you mention salt domes and anticlines…are there any others?)
I’ve often wondered that, especially about a surface like the ocean floor that can be quite uniform. Sand over here, oil, sand over there, no oil.
And what type of equipment (and with what success rate) is used to determine the actual amount of crude is in a given deposit, assuming you find some where you’re looking?
[/QUOTE]
We have a pretty good idea about the conditions under which oil can be found. We first looked for those on the surface because we had no tools to discern what was happening beneath. So anticlines, salt domes, fault ourcrops, basins, overthrusts, all these may carry a suggestion of reservoir, concentration and preservation.
You’re right though, sometimes on the surface we see nothing but uniformity. What then? Well, a couple of things. If we’ve drilled anywhere near in the subsurface, we can look at where we encounter the various strata as identified by electric logs and see if they’re thickening, thinning, dipping, changing lithologies, whatever. With seismic, we can extrapolate them well beyond what was prudent without it. You correlate a log signature to a seismic response and follow it, noting any changes in amplitude, any structures encountered, pinch-outs, etc. Your interpretation is based on huge amounts of case histories, theories on the physics of sound, reason and whatnot but more than anything else, just years of experience and good judgement. A seasoned geologist and geophysicist, actually teams of them, are indispensable.
As for determing the amount of crude in a deposit, it’s complicated but essentially you measure how thick the reservoir is, what percentage holds oil, how permeable it is and how far out cross sections or seismic suggest it continues. You’ve seen oil wells flaring gas? They’ll put a measurable choke diameter on a well and see what the pressure drop is over a given time interval and if it’s acceptable they’ll complete the well and bring it online. Actually, there’s a number of things they do but that’s kinda the gist of it.
[QUOTE=Fish]
Well, a grain of sand is 1/16 of a millimeter in diamater, right? How many nanoliters is that?
[/QUOTE]
I don’t know the shape of a grain of sand. If it’s a cube 1/16 of a millimeter on a side, the volume in question is equal to 44% of a grain of sand. If it’s a sphere 1/16 mm wide . . .
We can just say it’s half a grain of sand.
Thanks Lieu and NaturalBlond for the insight.
Obviously in the USA people are becoming more keenly aware of oil and it’s associated costs.
I saw a recent episode on Discovery HD where they showed how they lay the piping to connect wells to rigs, hubs, etc. It was utterly fascinating watching this ship that had an enormous welding operation going at all hours inside the hull and using some kind of a giant spool to play out the welded sections into the ocean, while a pipe supply ship was alongside, feeding the welding ship the necessary sections of pipe to keep going for miles and miles.
They mentioned something about that particular vessel being the only one of it’s kind in the world or some such. A couple glasses of wine and I was thoroughly engrossed.
Yeah, I saw that too. Pretty impressive. The industry requires such a disparate array of talents and knowledge, it’s tough for even those of us in the thick of it to be well-versed in much more than our own specialties. Exposure to the rest can just as informative and engrossing to the insider as it is to the layman.
Perhaps your wife is at the end of a game of telephone involving subsidence. For example, An oil extraction from a field near Long Beach, California resulted in subsidence over an area of about 50 km[sup]2[/sup] with a maximum of 9 m near the center. Such subsidence is more commonly associated with ground water extraction, though.
[QUOTE=Shagnasty]
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.
[/QUOTE]
That’s the story they want you to believe. According to very informative websites, they drilled that hole all the way to hell and shut it down out of fear.
FoieGrasIsEvil, you realize you have enough ammunition now to ruin your chance of ever having sex again for the rest of your life. Just tell her she’s right and enjoy.
I think the view of the OP’s wife has some merit. Have had lots of scientific well documented reasons why the “tiny” holes drilled in the giant earth will not have any devastating effect.
But what about all the billions of billions of tons of oil, don’t forget coal, emissions being pumped into the air daily, surly this is making the atmosphere heaver while the earth is getting lighter.
Something has got to give.
[QUOTE=FoieGrasIsEvil]
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!
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I am trying to piece together exactly how this thread is supposed to help the situation. “Honey, I asked the internet, they said you’re wrong and you have to put out now.”
If this actually works, can we work out some sort of temporary swap? Tell her everybody voted on it.
[QUOTE=Squink]
One billion barrels of oil (55 billion gallons)
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A barrel of oil is 42 gallons, not 55. One of the few bits of oil industry trivia that I do know…
[QUOTE=FairyChatMom]
A barrel of oil is 42 gallons, not 55…
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Silly me, of course the oil industry subscribes to the same dimensioning philosophy as the lumber industry. :smack:
Thanks, FCM, I did not know that.