Depletion (or not) of oil reserves

Factual Questions
1

I’ve recently read a couple of articles postulating that our previous estimates indicating that we would run out of oil by the mid twenty first are way off. Basically, this was based on the fact that many (most?) of the fields that should have been depleted years ago continue to be very productive, without the use of any technology to squeeze out any last drops. Some of the expert sources quoted speculate that there is an even greater quantity of crude oil far below our ability to detect it and that it keeps replenishing our known oil fields. Other experts seemed geniunely stumped. Some questions come to mind:

  1. Are we still that much in the dark about what the planetary structure is like a few miles below the surface?

  2. If there are vast oceans of oil below that we are gradually depleting, are we setting ourselves up for problems that are akin to mine subsidence on a larger scale? I understand that tectonics explains the drifting of the continental plates as the plates drift over one another on the earths magma. What if this thoeretical ocean of oil is gone? Can it affect the plate movement?

  3. There are implications for societal/economic/environmental issues. What if humans suddenly find out there are many times the reserves we once thought we had? Is everyone going to start driving 4-barrel V8’s again?

When you find yourself in a hole, stop digging.

2

I think there’s probably still sources of oil to be found, but it might not be so easy to get to, like Antarctica or the floor of the ocean. What might happen is that by mid to late 21st century all of the easy to reach oil might be depleted, and drilling for the more out of the way sources would cause prices to rise - one of the reasons we’re still so oil dependant is that it is still relatively cheap, so we really haven’t had to look for elsewhere for power. There was an issue of Discover magazine a couple of months ago with an article with the opinion that we would never run out of oil - the details of the article escape me right now. I think it had to do with a theory that oil is being created constantly.

3

Well, I’m not a petroleum engineer, but I’m a CPA and I do a lot of work with oilfield exploration companies in my line of work. A petroleum engineer or a geologist could give you a better answer, but they’re not here now, are they?

There are two different pieces here: 1.) oilfields that keep putting out oil more oil than was expected and then 2.) general growth in the world’s overall reserve levels

In the first case, it’s not that the oil is being replaced. Instead, these fields keep producing because apparently there was more oil there in the first place that we never saw when the original estimates were made. We have much better technology available today (satellite imaging, seismic devices, wirelines, optics) and we can find oil that was hidden twenty years ago.

In the second case, the world’s overall reserves keep increasing because new fields are constantly being discovered. In general, most of these new fields are being discovered in geological formations that were simply ignored the first time because no one thought they held oil. A lot of other new fields are also being discovered in places where no one ever bothered to look, like ocean floors and frontier regions in underdeveloped countries.

Honestly, all reserves eventually do run out. That’s the problem in West Texas nowadays - they’ve depleted those fields and now, many cities and school districts and populations are coming into very hard times because there simply isn’t any oil left. What good is an olympic size swimming pool when the school tax base isn’t big enough to fill it with water?

If you knew of some way to magically replenish the reserves, believe me, they would want to know.

4

I’m not a petroleum geologist, but I am a geologist (igneous petrology, volcanology, and geochemistry) who might be able to semi-competently answer some of your questions…

  1. Yes. Sort of. Everything we know about the deeper parts of the Earth’s crust come from either: (1) Drilling, (2) Geophysical exploration, and/or (3) Xenoliths. Drilling–as in for oil, gas, or water–provides the most direct information by allowing us to see the entire core or cuttings of the rocks between here and there. The problem is, we seldom dig much deeper than the top of the “basement” because all (most all) of the resources we’re drilling for are located above this! (The crust ranges in thickness between 3-5 km under ocean basins to up to 70 km under a large mountain range. Most of this thickness is “basement”–more ancient crystalline igneous and metamorphic rocks. The thin cover of sedimentary rocks that host our gas and oil occupies only a couple of km’s of thickness above the basement.) Therefore, most of what we know about the basement comes from geophysical methods (seismic profiles, tomography) which reveals to us the structure and the physical properties of the lower crust, but without “real” samples. Xenoliths are pieces of the lower crust and upper mantle that sometimes fall into a rising magma and wind up getting erupted, where they become the only true samples of the region just a few km deep that we have! In short, we know a helluva lot about the crust, but that’s still an area we don’t know that much about.

  2. First, to clarify, the Earth’s tectonic plates don’t scoot around on liquid magma. The lithospheric plates (which are relatively rigid and brittle) ride atop the asthenosphere (which is not liquid, but solid rock–albeit plastically deforming solid rock). Magma is liquid rock that is generated within the asthenosphere or lithosphere by a number of different processes which then ascends to give us igneous rocks. Even when magmas form in the asthenosphere, they do not comprise a significant volume of the asthenosphere. Oil–whether the abundance or lack thereof–does not affect tectonic motion. Since most oil is generated in and rests far above the base of the lithosphere in the upper sedimentary cover, it wouldn’t have a chance to interact, anyway. In terms of some local “tectonic” phenomena, however, the withdrawl of water and/or hydrocarbons has been linked to minor earthquakes in regions that (1) aren’t supposed to have earthquakes and (2) are centered in regions of significant pumping.

  3. As for our reserves… I dunno. Like I said, I don’t do petroleum. It is likely that we’ve got oodles of oil beneath us yet to be recovered and that it’s just a matter of time, technology, and a higher price per barrel before we extract it. A lot of oil being drilled for and pumped from here in Texas is from fields that were once thought to be depleted–but you’d be amazed at the precision drilling and exploration techniques available these days!

Anyway, that’s a volcano-person’s take on a petroleum problem.

Pantellerite
MS, Geology
PhD–ABD (“All but dissertation!”), Geology
and…Lecturer in Geology

5

Slightly off-topic, but germaine. In one sense we’ll never run out of oil – it will just get too expensive to extract. This is true of any natural resource. As the price of oil goes up and down the feasiblity of economically recovering it goes up and down too. If it costs $10/bbl to extract and we can sell it for $15/bbl, we’ve still got oil. If we can only sell it for $5/bbl, we’ve “run out”. So the size of reserves depends on the price. There will always be some oil left in the ground because it is prohibitively expensive to get it. The really expensive stuff and the really cheap stuff (pools of it lying on the surface) are the tail ends of a bell curve.

Of course, the same market forces which drive the price of oil up or down affect consumers as well as producers. If gasoline costs $5.00/gallon we’ll use less than if it costs $1.00/gallon. The point at which its value to consumers matches its value to producers determines its price.

Having said all that, we are continuing to consume the oil available at today’s prices at a prodigious rate. Regardless of undiscovered reserves, we will someday “run out” of cheap oil. High prices will drive usage down and allow more expensive production methods but the demand is not infinite. Alternatives that are not feasible today will become economically viable as the price continues to rise. So we will gradually (hopefully) move away from a petroleum-based economy.

All this assumes a free-market economy, which doesn’t exist today and probably never will. Taxes, cartels, tariffs, subsidies, etc., create artificial pressures which move the price around. It’s these sorts of machinations which lead to sudden rises (or collapses) in price, which leads to sudden shortages. Market forces, unencumbered, usually act much more gradually.

“The inability of science to grasp Quality, as an object of enquiry, makes it impossible for science to provide a scale of values.”
Robert Pirsig

6

It’s not just oil that is cheaper and more plentiful now. Twenty years ago or so Economist Julian Simon placed a bet with Paul Erlich, the guy who wrote “Limits to Growth”. Simon bet him that if they took a cross section of natural resource products and tracked their price, they would be cheaper in 10 years. Erlich laughed at this, since he was predicting massive shortages of many of these resources in that time frame.

Well, Erlich paid up. Most of our major natural resources have dropped in price in the last twenty years, indicating that we have more of them available now than we ever had. So, while no one can argue that eventually they have to be used up, to date any estimates brought forth for when that might happen have been horribly pessimistic.

7

Whew! A string of good replies!

IIRC, (and it’s been awhile since I read this) Simon’s thinking was that as we continued to exploit natural resources, we would get better at doing so and the increased efficiency would result in greater supply and concommitant lower prices.

Regarding the OP, I think Pantellerite covered 1) & 2) pretty well (BTW, welcome to the MB; we’re in different spheres, but I’ve been waiting for another geodoggie to show up).

I read an article a couple of years ago that said we’d consumed about 850 B(illion)B(arrels of)O(il) and had identified reserves equal to that; so at that point in time we’d used about half of what had been found. But we’d accomplished most of that consumption since ~1940. The authors of that piece estimated there remained about 150 BBO to be discovered. I just mucked around in my pile of interesting stuff I might like to read again to see how they got there and can’t find the article. Nevertheless, their estimates are different from others, as you would expect. That’s getting out in unprovable territory. My latest copy of World Oil had a column that noted in 1987 we had an estimated 28 year supply of domestic U.S.A. reserves behind pipe (i.e., already discovered, not yet produced). As of this year we have a 10 year supply. We burned what they thought was 18 years worth in 12. And this against a trend of reliance on imported oil. So, were burning the stuff like crazy and we don’t really know how much their is left to find, but we do know about how much of the planet might hold economic reserves and we know their is an effectively finite supply.

There are sources that have not been exploited as yet. Oil bearing shale cannot usually be produced via wellbore, but it can be produced by mining. Exxon had a large oil shale project going that died in the early 80’s because they could not get the cost of production below ~$40/bbl.

Which at this point causes me to think, good point about us never drilling for that last barrel, pluto! We will get to a point where alternative sources of energy finally cross the line and become economically viable.

I looked for oil today (truth be told, I was looking for gas). That’s what I do, I’m an exploration geophysicist. I’ve been doing it for two decades now and, frankly, it’s: a) harder, because we’re hunting smaller beasts and b) easier, because the technology and methods have improved so much. Until ~1992, the historical industry drilling success rate was around 1 out of 9 successful exploratory wells. That has improved with the advent of several technologies, particularily 3D seismic. This improvement has allowed us to pursue the exploitation of reserves that were bypassed in the past. In 1986, nobody drilled a 15 acre reservoir at 7,000 feet. Now we do. We still drill dry holes.

Another wild thing still out there but yet to be fully evaluated is Thomas Gold’s idea that there might possibly be untold reserves of abiogenic methane tappable, ultimately sourced from the asthenosphere. We’ll have to wait for the price to get right to find out about that. And don’t forget that we use ~40% of the oil we produce for purposes other than burning for energy. Petroleum products like plastics, etc., are quite a part of society at this point.

End of story? If you’re younger than me (46) you’re probably going to see the place of hydrocarbons as an energy source change in your lifetime. Major unanticipated discoveries are possible, and they may change end of the viability of toasted paleoplankton as an energy source by a decade or two. I doubt your grandkiddies your know what a gas station is.

All this brings to mind something I don’t know anything about. I know that towards the end of WWII, the Nazis were rolling on synthetic oil production. Anybody here up to speed on that?

Regards

8

I hate screwing up a post, and I’m not even going to post the change; I think y’all will see what needs to be done and do it in your heads.

Peas

9

I’m glad beatle mentioned Thomas Gold. I neglected the Cornell astrophysicist in my post and restricted my discussion to “mainstream” geological thought (i.e., making the assumption that all oil is biogenic), although not necessarily because I have a strong opinion either way. Whenever I’ve asked a petroleum geologist–or even once a planetary geologist–about T.G., I’ve gotten at best an eye-rolling response and at worst a comment about his “crackpot theories”. As someone not involved in that end of the science, I’ve never felt fully qualified to hold an opinion and usually teach the “party line” to students while secretly harboring feelings that I’d like T.G. to be right! In short, his hypothesis is that not all hydrocarbons are biogenic, but that most of them (including large amounts in the deep lower crust and asthenosphere) were formed during the condensation of our solar system. His argument is simple: if we accept that the vast clouds of hydrocarbons that are found in the outer planets (especially Uranus and Neptune) are abiogenic, then why can’t our terrestrial hydrocarbons also be abiogenic? He’s drilled into fractured cratonic basement (granite) in Sweeden to test his hypothesis, but I don’t know how that worked out for him. In any case, most all of your hydrocarbon exploration companies are going to continue to invest in better-proven theories of biogenic exploration before they start sinking multi-million dollar holes in basement!

beatle’s final comment also sparked a memory about something I was told when I was a kid: apparently the Nazi’s–being cut off from their oil supplies–developed a formula that allowed their engines to run on pure ethanol without significant corrosion, but that this formula was lost in the aftermath of the war (I was also told that Texas A&M has been trying to replicate the Nazi Alcohol Fixing Formula, too). This story may be apocryphal, but it fits in with the alternative fuels sub-thread that’s developed.

Pantellerite

10

Usually when I’ve heard “synthetic” petroleum mentioned they were talking about converting coal to oil. IIRC, this is already “do-able” but not cost effective. We have to wait for the price of oil to go up first, and once it becomes a mainstream technology there will be additional improvements which will bring the cost down.

On the up side we have humongous coal reserves in the U.S. On the down side it is dirtier than petroleum, still produces CO2 and even though the reserves are large we will one day run out.

re: Thomas Gold – see the “Lakes Turning Over” thread. The high CO2 content in these lakes was used by Gold as supporting his hypothesis. Others have discounted it as a local phenomenon accounted for by volcanism.

“The inability of science to grasp Quality, as an object of enquiry, makes it impossible for science to provide a scale of values.”
Robert Pirsig

11

Anyway, as oil gets more expensive, we’ll start opening up a lot of oil-bearing resources that we know exist but are not cost-effective. The Athabasca Tar Sands project comes immediately to mind.

Electric and hybrid vehicles are available which perform as well as or better than gas powered vehicles in every area except range, and in the case of hybrids even that’s not an issue. They just aren’t in mass use yet because of cost. There will be a threshold oil price which will suddenly cause a mass exodus over to electric power.

Someday the wackos may lose their stranglehold on the nuclear industry, and we’ll see a rebirth of nuclear power. If we ever do see a mass exodus to electric vehicles this may even be the catalyst for the rebirth of nuclear, since current electrical demands are already putting a heavy strain on the grid. Add a few million electric cars that need to be charged every day, and you’re going to need a lot more power plants.

So we’re never going to ‘run out’ of oil. It’ll just get more expensive to the point where we stop using it in a massive way.

12

dhanson…
According to most the magazine articles I’ve read it’s not just range but accerleration as well, at least in the pure electrics. I think fuel cells will be the next big thing in automotive rather than electric.

13

Acceleration? The first commercial Ford Electric does 0-60 in less than 7 seconds. Although I’m sure a lead foot would kill your range.

14

beatle posted 10-14-1999 08:39 PM

To be the devil's advocate: do really **know** that it's finite? I mean, I looked at a model of octane, which is supposedly impossible to create except in certain extremely rare conditions, and hemoglobin, which is created every day by even the simplest animals, and to my untrained eyes the hemoglobin molecule looks a *lot* more complicated. I suppose octane has a much greater H (I don't remember what H represents), but adding more energy should take of that. I realize that there are many aspects of this subject that I don't understand, and I certainly don't think that just because I don't see why petroleum can't be synthesized means that it can. But I haven't had satisfactory explanation of why petroleum is considered non-renewable.

dhanson posted 10-15-1999 12:24 PM

From what I’ve heard, nuclear power plants are horribly cost-ineffective. Of course, this may just be propaganda from the “wackos”, but maybe it’s not. After all, what we really want from an energy source is work, not heat. That’s why the internal combustion engine was such an imporovement over the steam engine; the steam engine creates a heat differential, which must then be transformed into work. In an ICE, the energy from the fuel goes directly into pushing the piston, creating work, not heat. Putting a bunch of uranium in a piston and fissioning it just doesn’t work, which means we’re back to heat engine technology. And not just any old heat, but radioactive heat (well, technically the heat itself isn’t radioactive, but still…). All the shielding gets pretty expensive.

15

The Ryan

This thread isn’t that long, so I’ll not C&P. If I’m following you, you’re kind of posting two questions w/regard to your quote from me. The first would be: can we synthesize hydrocarbons? As I touched upon above, I don’t really know the answer, I really now just look for the in situ biogenic and commercially viable HCs. If you look into synthetic fuels, most of what you’ll find is really just highgrading inferior quality naturally occurring stuff like extraction from oil shale or tar sands. It’s out of my range to comment offhand on the possibility of dragging a bag of carbon molecules and a (bigger) bag of hydrogen molecules down to the lab and sticking them together. If it involved a juicy contract, by Monday AM I could probably have something to say on the subject. Along the lines other posters have pursued, if somebody knew how to do this economically they’d be doing it - and they’re not.

The other question I perceived in your post regarding my quote was the use of non-renewable as a term to describe petroleum reserves. When you see that usage the context referred to is the conventionally accepted model of our petroleum coming from biogenic reserves. They are not strictly speaking non-renewable. Economically and practically speaking, they are. Earth processes continue and new hydrocarbon reserves were created today. But our rate of exploitation of these reserves far outpaces the earth’s ability to renew them. So we will reach the economic point of no return with regard to these reserves at a point not too far off in the future.

Calling to mind an earlier poster’s reference to the Simon-Erlich bet, I suppose it’s possible the utilization of the non-wellbore-recoverable (ACK! Did I really just type that?) reserves might become significant enough to drive development of technology that allows them viability. And so would extend our reliance on HCs for a while. Perhaps long enough for synthesis to become viable?

As long as I’m here, let me address the nuke thing. I am not qualified, or, apparently, as qualified as you, to comment on this. Heat energy v. work. Did I get that right? Right now the majority of our power plants are coal or gas or cogeneration facilities. Unless I missed a big something, they burn the stuff and generate heat, which they convert to power they can transmit. Is there something different about nuke heat v. coal heat?

16

As I recall, the only reason nuclear power plants are so expensive is because of the insane regulations that have been dumped on them. There’s nothing intrinsic about nuclear power that means it has to be expensive.

Canada is a world leader in using nuclear power, and our plants are extremely clean, safe, and cost-effective. Hell, our university in Edmonton has a mini-reactor that’s used for research but actually can generate power for general use.

18

Reported

19

this is amazing, if one of the og members replies to me ill cry

20

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