Fossil Fuels

A comment in this thread, on Global Warming, as well as a conversation I had recently, caused me to reflect on world oil supplies and consumption. Just how much oil is left in the earth and how long will these supplies last. Now, I realize this is open to speculation and opinion, as well as the accuracy of usage and exploration models, but does a “best guess” exist that is generally agreed upon by the petroleum industry? I remember seeing some numbers, in years past, that tried to estimate how much oil had ever existed vs. how much we’ve burned, and the remaining quantity ranged from “we’ve already run out” to “several hundred years worth.” Have these numbers been “refined” recently?

The how long it will last question is really a moot point. It will last for as long as it needs to.

When supply (real or inforced) levels get lower the price will go up and other ways of lighting the world will be used.

Oil is like diamonds and gold, its really not that rare, only kept that way too keep a few people very rich.


My new Discover magazine had a chart in it regarding the oil supply, and according to the chart it is all downhill from here. However, I would guess that there is still a lot of oil left, but it might be increasingly difficult to get to, such as the ocean floor or Antarctica.

This web site ( ) claims 980 billion barrels left to produce in the world lasting out till around 2050. However, they paint a bleak picture because almost all of that oil lies in 5 Middle Eastern countries.

This particular web site maintains that the worldwide midpoint of oil production will arrive in 2003. After that world oil production can only decrease. The theory being that no matter how hard you try only so much oil can be extracted and shipped from a relatively few oil fields as the other ones the world maintains dry up. This, of course, will cause oil prices to rise dramatically.

This will also lead to a HUGE dependence on mid-eastern countries. As OPEC gains a greater and greater strangle hold on oil and Americans keep buying SUV’s OPEC will end up owning us.

Looks like a recipe for war if there ever was one…

According to the API, the U.S. Geological Survey estimates that the Earth could hold as much as 2.1 trillion barrels of crude oil; enough to supply the world with oil for the next 63 to 95 years, with a 95% confidence level. Interesting numbers. I can remember three years ago, they said it would last 50 to 100 years. Of course, this is with all the market factors discussed above. See:

Coal is a different story though. IIRC, both the USA and China have enough coal to last about 400 years. But I’ll let Anthracite handle that one.

Just happened to catch the news tonight and it was reported that OPEC is currently responsible for 27% of the daily oil production. The political focus is always on the Middle East but there is an awful lot of oil elsewhere.

Personally, I hope we run out as soon as possible. If much those ice caps keep melting I’ll be swimming to work - through a semi-desert and with a lovely ozone free tan

Owing to recent discoveries of unexpectedly large fields in the Caspian, Africa, Siberia, and off Greenland, the feds have recently adjusted the outlook for the better, according to the September edition of Scientific American (whose link appears to be broken right now). The USGS now estimates world oil reserves at 649 billion barrels. This is known oil reserves, as opposed to TNTruth’s estimated world figures from the same source, USGS. This could be as much as half or as little as a third of worldwide oil.

However, Colin Campbell, who penned “The End of Cheap Oil” in the March, 1998 edition of SciAm (and not posted online) still disagrees with these figures. Campbell points out that while reserves may continue to increase for a while, most of the oil that will be discovered in the future will be more difficult to recover and therefore more expensive. Once we are on the far end of the cheap oil curve (I forget Campbell’s prediction, but it is like, soon–fifteen years, maybe?) oil prices will swiftly rise. The second oil becomes more expensive than anything else, oil consumption will begin to diminish, but it won’t go back to being any cheaper. We’re probably just going to have to accept a much higher price for energy.

But fusion, of course, is only twenty years away–and has been for the last fifty years.

Ah, at last a thread I can really contribute to.

I worked on the exploration side of the industry for 17 years, although not in the field of reserves estimation. Nevertheless, I help out with some data.

According to an article in Oil and Gas Journal (Feb. 1, 1999, “World oil supply-what goes up must come down, but when will it peak?” by J. H. Laherre)…

…“The DOE (Department of Energy)(estimated) future production is around 3,900 billion bbl, which added to the present cumulative production of 800 billion bbl gives an ultimate of 4,700 billion bbl of $20-25/bbl reserves. The IEA (International Energy Agency) future production is around 2,000 billion bbl, giving an ultimate of 2,800 billion bbl…”

In this and several other articles I have seen, it is generally agreed that the peak of oil discoveries (and thus addition to total reserves) will occur sometime between now and about 2020. There is a considerable time lag, however, between the peak of discovery and the peak of production, due to the years-long process of installing production infrastructure in each discovered field. This can be seen in US production figures, with the reserves peak achieved in the 1930’s and the production peak around 1970.

If a similar scenario holds true for the rest of the world, then the production peak should take place sometime between 2060 and 2080. Add another 20 years before prices begin to rise significantly due to production constraints. YMMV. :smiley:

A few points to ponder:

  1. the above estimates estimate peak production at about 45 billion bbl./year. Current yearly consumption, I believe, is in the mid-30 billion bbl. range, and rising. Unfortunately, I can’t recall the avwerage rate of increase per year.

  2. So-called “supergiant” oil fields are in the 3-8 billion bbl. range, yet at current rates of consumption, discovery of one new supergiant field per year would only delay the peak by about a month.

  3. Reserves estimates are notoriously unreliable outside the USA, with certain countries “padding” their estimates heavily, both to attract further investment, and (for OPEC members) to enable the negotiation of higher production quotas. It is easy to play with these numbers by manipulating the recoverable percentage for each field, which in practice is somewhere between 30% and 60% of total oil in place.

  4. Natural gas reserves, in barrels of oil equivalent, are significantly larger than oil reserves, and have so far been exploited to a lesser degree.

  5. Despite continuous improvements in the technology of oil exploration since the days of Fransics Drake, on average only 1 to 3 of every ten exploration wells drilled results in a new field discovery. This has remained the case for decades.


“If a similar scenario holds true for the rest of the world, then the production peak should take place sometime between 2060 and 2080.”

Whoops, should be 2040 and 2060…

…and Edwin Drake, how embarrassing.

Never post tired…

How much is there and how long will it last are dual moving targets, Unc. I’ve read the Colin Campbell (didn’t he have a coauthor?) article cited above and seem to recall him giving figures of 850 BBO consumed, 800 BBO established reserves and 150 BBO yet to be found.

Estimates are based on what people currently know. If you’re old enough to recall the 1973 oil embargo, you might remember that estimates on the order of 20 to 30 years of remaining hydrocarbon supplies were bandied about. Any appraisal of yet to be discovered reserves will be based on what we know about the planet’s geological composition and will be based on historical experience as to what can be expected from any potentially productive basin. And such estimates vary quite a bit. Known reserves are estimates as well, with some reservoirs doing far better than expected, while many fail to achieve expected production. And, in light of political and business considerations, one must take estimates of established reserves with a grain of salt.

While there are several areas that have not been explored sufficiently to assess their potential (I predict we will drill ANWR), there are many other productive regions whose potential has been underestimated in the past. These underestimates have been, to a large part, due to having been made based on the historical experience available both with regard to field performance and existing technology. We are very much more efficient in identifying and extracting hydrocarbons than we were just 15 years ago. This counterbalances to some degree the contention reported by Sofa King that much in the way of new reserves will be difficult and expensive to produce. Yes, a lot of future discoveries will be such - we drill deeper in nastier environments these days, but exploitation of those reserves will be offset in expense, to some degree, by the cheaper and easier exploitation of others. I work primarily in the most mature exploration province in the world - Gulf Coast, USA - and I remember being told at the start of my career (20 years ago) that I should seek foreign work, as there wasn’t much left to be done. We’ve found a lot since then, and there’s much left to be done.

As an example, 10 years ago you could not easily exploit (i.e., convince enough people to get it drilled) an exploration play keying off of a 25’ fault that setup a 2 Bcf potential field - the picking and tracking of such was not reliable enough with the data you could get your hands on to make it an after risk economically viable effort in the market of the time (I did get a 40’ antithetic fault play drilled in 1988 on 2D data, but man it took some talkin’). That’s not as hard, now, with 3D seismic, so these formerly bypassed reserves are getting drilled.

I can tell I’m going to meander - anyway, suffice to say that predictions are based on making estimations of multiple unknowns - something we do all the time just to stay in the game.

The how long will it last side of the equation is similarly subject to dealing with unknowns. We do know third world demand is going to increase, dramatically, as their industrial revolution progresses (they’ve already had their great stock market crash). But we really don’t know how much and how fast. While we took many measures to conserve beginning in the '70s, we nevertheless saw the SUV boom in the '90s. We’ve seen a great swing toward the use of natural gas and an abandonment of nukes.

And I look back on my own short life and have to think that the political layout of the planet may well be quite different in 30 years. So, it may not matter that all the substantial new reserves are in 5 mid-eastern countries. And, that’s not a given - it’s quite conceivable that the top 5 producers in 30 years will include China and Russia (Russia’s currently in the top 4, along with Saudia Arabia, Kuwait and the USA).

I peeked in on this thread before posting what took me an hour to ramble. In the meantime Rocket88 made an informative post (thank you, sir) that included (italics mine):

Just reiterating some of what I said about appraisals of the future…

So, firm enough answer for you, Unc? I’ll give you a bit from the gut. I think we will find quite a bit more than 150 BBO yet and I expect that, as I approach old age (I’m 47 now - so, in ~25 years) I’ll see the beginnings of earnest movement away from our current state of dependance on fossil fuels. Natural gas use has a substantial history ahead of it, and it’s likely oil consumption will be steered away from use for energy toward the other 40% of what we use it for (manufacturing, plastics, lubricant, etc.). The old equation telling us it’s cheaper to use Brand X Energy will have to come into play before the switch gets underway. And, I suspect, when the switch happens, it’ll be fast.

Ooh! And what if Thomas Gold is right? They’re not many banking on that, but, if he is and the exploitation technology is commercially viable before Brand X dominates…

While this thread is getting some professional attention, I’d like to toss in a follow-up. I recall reading somewhere that one country, Sweden perhaps?, was going into a completely different line of exploration. They had the theory that enormous reserves might be trapped vertically in fault-lines. How has this research played out so far?

I believe, SK, that you’re thinking of the test drilling that was done (mid '80s, I think) around thhe Siljan ring in attempt to confirm Thomas Gold’s idea that abiogenic methane might be produced from below the earth’s crust. The Siljan ring is a fracture zone resulting from a meteor impact and the idea was that sub-crustal methane might migrate up the fractures, allowing confirmation of Gold’s idea without having to drill all the way through the lithosphere. I don’t have a lot of time right now, but you can read more about it at the following sites, or search for Gold or the Siljan Ring.

  • a brief overview:

  • Thomas Gold on the subject:

Thanks for all the info, guys. The breadth and depth of knowledge here never ceases to amaze me.

My question: why don’t we switch from oil to natural gas? the stuff is so cheap that they don’t even bother saving it (in the Middle East they just burn it off at the wellhead).We have a country-wide gas pipeline system now, so we can distribute the stuff easily.
Unrelated matter: some years ago I read about a guy who was studying old oilfields-he examined some old oilwells which had been capped off since the 1960’s-lo and behold, many of them had oil in them. So it appears that oilfieds do recharge themselves-might this be proof of Dr. Gold’s ideas?

The main problem is transport over distances longer than the few hundred miles typical of a pipeline; across an ocean, for example. Methane (the main component of natural gas) remains difficult to handle and cannot easily be liquified like heaver hydrocarbon gases, such as propane and butane. Besides, current prices would likely make it uneconomic to transport it by the shipload.

That said, many fields now reinject produced gas, to help maintain reservoir pressure and thus increase oil recovery rates.

I believe Dr. Gold’s ideas are particular to natural gas (specifically methane), which may not alway be of organic origin. It is generally agreed, however, that petroleum IS of organic origin and thus deposited from surface (or sea bed); in addition, oil is degraded by high temperatures and pressures and cannot exist below certain depths (different in every basin, but usually below 25,000 feet).

Most any abandoned oil well leaves some hydrocarbons remaining in the reservoir, which eventually may make their way up the well bore. The reason a well is abandoned is not because there is no more oil or gas to be extracted at all, but because the money earned by producing fluid is less than the cost of bringing bringing it to surface and transporting it. I recall reading of low-rate wells in Kansas, for example, that were abandoned in the early '80’s, when crude prices were relatively low, but reopened and produced in the '90’s, when crude prices were high enough to justify their low production rates (we’re talking only 5-10 bbl/day here; 1 bbl= 42 gal.).