Gas fields also deplete, but faster
Posted by Heading Out on November 19, 2005 - 2:04am
When one taps an oil reservoir the oil requires a certain amount of differential pressure to push it towards the well, and with the passages it must pass being generally narrow, flow is relatively constricted. Good well management means that, in order to control water and gas problems, the pressure difference between the well and the rock is carefully controlled, and this allows the oil to be effectively recovered at rates which, while worryingly increasing, are still generally considered to be less than 10%..
Natural gas, on the other hand, flows a lot more easily, and normally does not have a lot of the constraints that producing oil has. Thus, if your pipeline can handle the flow, and there is a demand, the gas field can be drained much more rapidly, with a consequent dramatically more rapid conclusion to the flow. As Dr Campbell pointed out fields may last just months, and then "boom" they are gone.
the average production from natural gas wells that began producing in 1996 was 69 percent lower than it had been at its peak. In contrast, the decline in production over the 23 months after wells drilled in 1972 had reached their peak production was only 39 percent.Alan Greenspan in his testimony in 2003 pointed out that as more tight sands were produced the rate of decline was reduced, because of slower flow and this brought the average back to 27%.
There is a natural gas primer that, as well as quoting Charlie Brister, also points out that for the average new Texas well, the first year decline in production is 56% and that half the gas in the well is produced in the first two years. It was written in 2001.
More recently Dominion points out that depletion rates are up to 28% with it taking between 6 and 18 months to get a new well production to market. There is a case study from the Maui field in New Zealand
Production this year (2004) was 21.6% less than the 2003. Production in 2003 was 33.5% less than in 2002. In 2002 the Maui natural gas field produced a volume of gas higher than it ever had in its past.. The article notes that the gas from this field provides 25% of New Zealand electric power. The field is now apparently anticipated to be completely closed by 2007.
It is this unwelcome fact that means that the major efforts to drill for more gas production will be no longer be able to keep up with losses, as we discussed earlier. But then if we think it is bad here, the graph that civ101 posted on UK gas production shows where this is all heading, rather rapidly I am afraid.
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But plastic use (as it pertains to peak oil) is such a small contributer compared to transportation fuel use. It seems a waste of mental energy to worry about paper versus plastic at the grocery store, and then put everything in the trunk of your car and drive back to your natural gas heated and electrified home.
Of course, every little bit helps.
So using natural gas this way is not a bad idea since it is used twice: once for extracting liquid hydrocarbons and finally as a fuel after all liquids are gone.
Is this correct?
To get oil from tar sands requires steam and heat to melt the tar and loosen it fron the source rock. The natural gas is used to create this steam.
You are thinking of other types of oil fields where gas (usually CO2 if i'm not mistaken) is injected in much the same way water is to push the flowing oil toward a recovery well. But this doesn't work for oil sand because the oil trapped in the sand is too thick to flow at all.
Say Canada used x amount of Nat gas. Does this take into account the gas that is extracted out of the ground with oil, separated, and then used to power the equipment to get the next batch of gas/oil?
Or is this only the amount that is bought and sold on the market?
This might be a huge problem in countries that have both large amounts of gas and oil. They must decide how much gas they need to extract oil. And it would be a big problem if a country underestimated how much gas they need for their population and their oil production. For this I see many countries holding out their Nat gas reserves just is case.
It seems the only countries that can be relied on for large amount of LNG exports, are countries that have smaller amounts of oil, Qatar, Algeria, Austrailia....
http://www.bp.com/genericsection.do?categoryId=92&contentId=7005893
The NG situation doesn't lend itself to quick analysis. There is lots of gas, but much of it is "stranded," located far away from major consumers. According to BP, the Reserve/Production ratio (R/P) in 2004 was 66.7 years for NG, versus 40.5 years. There may be, in theory, 66 years' supply, but there is also a possibility of cold homes in North America and UK this winter due to localized shortages.
Consumption trends are not encouraging. Per BP:
Has anybody seen a chart of future (SWAG) natural gas supply, for the US only?
Something similar to the ASPO Oil and Gas Production Profiles...but only for Natural Gas and only for the US.
Thanks,
Rick DeZeeuw
PS - SWAG stands for Scientific Wild Ass Guess
http://www.aspo-usa.org/proceedings/powerpoint/
His is labelled the Built Environment.
Thanks,
Rick
the average production from natural gas wells that began producing in 1996 was 69 percent lower than it had been at its peak. In contrast, the decline in production over the 23 months after wells drilled in 1972 had reached their peak production was only 39 percent.
Alan Greenspan in his testimony in 2003 pointed out that as more tight sands were produced the rate of decline was reduced, because of slower flow and this brought the average back to 27%.
There is a natural gas primer that, as well as quoting Charlie Brister, also points out that for the average new Texas well, the first year decline in production is 56% and that half the gas in the well is produced in the first two years. It was written in 2001.
More recently Dominion points out that depletion rates are up to 28% with it taking between 6 and 18 months to get a new well production to market. There is a case study from the Maui field in New ZealandProduction
this year (2004) was 21.6% less than the 2003. Production in 2003 was 33.5% less than in 2002. In 2002 the Maui natural gas field produced a volume of gas higher than it ever had in its past.. The article notes that the gas from this field provides 25% of New Zealand electric power. The field is now apparently anticipated
Garbage Into Oil
Oil from Anything
Changing World Technologies
Reading through the Energybulletin.net digest for today I came upon this article at
http://newerainvestor.blogspot.com/2005/11/full-throttle-decline-rates.html
The excerpt chosen for the EnergyBulletin is below:
Now I'm confused how anyone is going to prevent fields from being depleted? If the financial incentive exists (and it seems like it certainly will) why wouldn't someone want to pump more now? I suppose we can see the Iranians holding back some supply now, but how much of a long term decision is that? How likely is it that Saudi Arabia or any of the other in-the-USofA's-pocket governments will hold back oil for themselves? To do so would fly in the face of the global economy (which I'm all about deconstructing), right? I feel like there's something I'm missing about this article. Help?
Some analysts predict that once it's evident that we really are starting to run out of oil, gas stations will go dry overnight. Oil will be reserved for government and military use.
I don't know if that would be such a bad idea. We do live in democracies (I do, at least) and in the seventies oilcrisis there was rationing of gasoline, which is a form of handing out seized gasoline by the goverment I'd say. I think that in shrinking economies a governmental overview to assure we all get what we need, and not as much as we would want, is not such a bad idea.
This might be considered "socialism" by many, but do keep in mind that the New Deal was called socialism too. Yet the governments in the nineteenthirties that stuck to free market principles were the ones that fared the worst during the depression.
If, OTOH, the government confiscates the oil so the Bush family yachts can keep running, or to make war on Canada in order to seize the tar sands...I'd be lot less enthusiastic.
I've recently realised that the "dieoff" crowd has a very American way of looking at things in expecting that the post oil world would be individual against individual all over the world. My gues would be that things won't turn out that way. There are completely different preconditions for different places that could influence the possible outcome of peak oil. What peak oil (and peak NG) will cause IMHO is that local problem will be exaggerated. Look for instance at Zimbabwe. Its government made the huge mistake to expel experienced farmers without having a good plan of how to make sure agricultural production is kept at its level. Even without high oilprices that would have caused trouble but since oilprices have risen it starts to become a catastrophe.
Cuba on the other hand experienced a form of peakoil due to the collaps of the Soviet Union. While suffering a great decline in the standard of living they did manage to addapt agricultural production to the new realities.
http://www.harpers.org/TheCubaDiet.html
All kinds of factors could have enormous impact locally: The state of technology (While it may not able to turn the tide it certainly might be able to mitigate at crucial moments the worst effects), the state of the land (Erosion, salification) and the state of the nation (How willing the people are to cooperate) all influence the future.
Mind you, these are just some loose thoughts but I think becoming politically active, in other words trying to clean up the mess before this hits us might very well be an important part of how we should prepare for peak oil.
http://www.crownminerals.govt.nz/petroleum/facts/gas-stats.html
This page has links to small Excel spreadsheets with the data. There is annual production data from 1970 to 2004 for a total of 9 New Zealand gas fields, of which 6 are in serious decline. There is also data on total reserves and remaining reserves for these fields, using 50% probability estimate.
My guess is that the production data is quite accurate, and the reserves numbers are probably open to some speculation, but not falsified.
It does not make for a pretty picture. Sadly, until 1998 we had a great government-subsidized Methanex facility that converted NG to either gasoline or methanol, whichever fetched a higher price at the time. Now that prices are high enough to make it profitable, the NG feedstock needed is gone.
Crisis, what crisis? The Government can hardly be blamed for the weather but it is responsible for the country's energy policy. Having denied for months that we are in danger of running out of gas this winter, there is a sudden sense of panic in the Downing Street air now that the temperature has begun to drop.
Those who warned of trouble ahead, such as the CBI's Sir Digby Jones, were accused of being scaremongers. Now we know that Tony Blair was sufficiently concerned to convene a secret meeting with industry representatives nine days ago to discuss just such an eventuality.
Ministers wanted to find out how much big industrial users could cut their consumption by in order to keep the home fires burning and, second, what impact the resulting decline in output would have on the economy. Consultants have now been hired to crunch the numbers.
The National Grid reckons that in the event of a Siberian-style winter, the like of which Britain experiences only once in every 50 years, industrial consumption would need to halve for the best part of two months. Even a one in ten type winter would require a 30 per cent reduction in demand for 40 days. The Met Office, for its part, reckons there is 65 per cent chance of a colder than average winter this year and a 35 per cent chance of it being a severe one.
Could the Government have done more to prepare for this eventuality? Yes, it could. Indeed, the looming power crisis this winter was entirely predictable. Ministers have known for years that North Sea supplies were running out, turning the UK into a net importer of gas.
Yet no serious effort has been made to ensure greater diversity in energy supply beyond measures to encourage renewables. To the contrary, the fact that Britain relies more and more on gas for her energy needs is largely down to government policy, which deliberately or otherwise, encouraged a dash for gas among power generators.
Extra gas storage and import capacity is being built but it will not be on stream in time for this winter. Meanwhile, the additional facilities that have been built, such as National Grid's LNG terminal on the Isle of Grain, lie idle because the shippers have found they can get higher prices in Spain and America. Those, however, are the laws of the market.
The prospect of a three-day week for industry will not warm the cockles of Mr Blair's heart any more than the idea of householders running out of gas to fire their central heating systems. Whether we run out or not, still higher fuel bills are a certainty. If there is a small sliver of consolation for the Prime Minister, it is that an energy crisis this winter will make the case for new nuclear build unassailable.
http://www.dailykos.com/story/2005/11/20/121814/88