Robert the function that ties production rate to URR is a unknown non-linear function. HL is a way to guess the answer without knowing this function. Thats why its empirical.

The one example you gave that was even close to reality was giving HL answers that were not too bad.

What you have just wrote says nothing about HL it's basically garbage.

If you come up with something close to right its worth arguing about. Your so hell bent on proving HL wrong your not even trying to understand it.

You can keep being unreasonable or start thinking.

I gave you a hint the shape of the function is not that critical. It can be a Gaussian or a square wave.
And I told you the reason HL works is regardless of the shape of the curve the peak time and total URR are basically constants thats why HL works. The model HL uses is the Logistic curve.

http://mobjectivist.blogspot.com/2005/12/hubbert-linearization.html

Most analysts use the logistic curve or Verhulst equation to "prove" this limiting behavior. Whereas, in practice, any peak will do.

He is basically right. We just happen to know the logistic curve seems to give the best fit for a simple analysis.
It seems that these unkown non-linear functions that relate production to URR can be mapped to a logistic curve. Of course the probably map to others. I'm not convinced logistic is the best but I think the error in the data is high enough it does not matter.

So again go back and pick any non-linear function that maps production rate to URR use that to generate your production data then run HL on the results. I'd like to see the graph
of the production profile so I can visualize the function.
The 5% per year one is basically I triangle if I understood
what your saying.

Then and only then can we discuss HL.
If at this point you have some valid arguments I'm interested. I know I'm being a bit harsh but this is bogus
and its public.

One more time.

Its too early to throw out HL.

Memmel,
Robert has an interesting point though. As he accurately describes a situation (Oilsville) with a flat production rate, what happens is that the width of the upside down parabola begins to increase; i.e. the second derivative of the production profile starts shrinking.

This kicks the y-intercept further and further into the future. Which you can mathematically see in that blog post of mine that you referenced.

Actually in the case you mentioned HL still works since the
peak comes down as the curve flattens. So as long as its a parabola your ok.

Generally flat production happens on the backside when production is constrained the case I use is a well that 90% watered out and the rate of production is constrained by how much water you can handle.
HL is not a good method once your constrained by above ground factors. Remember there is still a lot of oil left behind even after a well has watered out so its being produced at a low production rate basically forever for all intents and purposes. But where it fails your way past peak production anyway so whats the point ?

You can also of course come up with a number of contrived cases where a field is not reasonably exploited and these would show a flat production at the beginning. I don't know of a real world case that fits this.

One we have is Russia which collapsed where production collapsed for several years then rebounded slowly. And this one is problematic.

I might add there is a chance here to have a good discussion on HL and it needs to be examined but lets at the minimum start the discussion with the right baseline in place.
I have not varied all the constant volume parabolas to see if you can introduce some numerical instability into the procedure but mathematically all your doing is a trick integration of the parabola so all true parabolas with the same area give the same answer.

The real important piece that gets dropped on the floor it seems like is Hubbert is assuming a parabola or Gaussian shaped distribution the area under the curve is a constant
this makes the "date" of peak a constant just the shape of the curve is changing so what really changes is the amount produced at peak but this is not so important. If you have enough points on the curve then you can get both. I don't understand the choice of the logistic function over others but as I've said a few times I don't think it matters to much given the quality of the data. HL has real issues that should be addressed. They have not so far.
In any case you have to use curves the might is well be parabolas since you taylor expand with constant volume/URR
and linearize those the get the numerical instability.
Other curves i.e Gaussian are interesting but this is secondary. What Robert has shown so far is not that interesting.

Btw I'd be happy to talk with WebHubbleTelescope on the issue.

He at least seems to understands the problem.
He rejected HL and generally I AGREE WITH HIM.
Sorry for the caps but your not listening.
Someone has already done a fantastic job of questioning HL
and he used the correct production profile.

Until you integrate his work I'm not sure what the heck your doing.

http://mobjectivist.blogspot.com/2005/12/hubbert-linearization.html

One more quote from his blog.

I checked the math on this, and it really gets you thinking about what data visualization expert Tufte says about graphing data in a biased fashion. That convergence on a continuously shrinking error acts like a laser beam and gives people the impression of an excellent fit that may have dubious value at best.

So a good well reasoned rebuke of HL already exists.
And I'll say one more time generally I agree with him.
But its not clear that he can come up with a better model given the data we have. Not that he can't create a better model or a better model is possible simply do we have enough
data to support a better model.

So again does HL have problems yes here is the link that points out its flaws.

My answer as to why it works is simple.

Although the function changes that describes the actual production profile HL implicitly assumes that the rate of production is related to the overall URR via the logistic curve. Since we know from theoretical plate models that the time of elution or peak is related to the interaction of the
material with environment with a given geology if you steadily pump a field the time of peak does not change.
This means you can change the shape of the curve but your not actually able to change URR or the date of peak by much
without massive changes in the way the field is pumped.

In the case of chromatography they use Guassians and derive the interaction numbers i.e theoretical plates.
Now using a model that is well understood and tested the Theoretical Plate model and applying it to a oil field its says the following. If I drill a well into a porous geologic formation and a few wells around it. And first I pump some oil down it then start pumping water. The wells in a circle around the pumped well will get the oil in a Gaussian profile. The main body of the oil has a interaction with its it surroundings thats FIXED!
In the case of a field full of oil this block of oil is moving through a system that has immobile oil as part of its
environment but the behavior is no different. As you begin to produce a field the main driving force is oil pushing oil. Later its water pushing oil but the little Gaussian regions can't move till the ones behind them move.

This is my interpretation of what Fractional_Flow says and he
is also correct its the field geology that determines the peak.
http://europe.theoildrum.com/node/2372#comment-170481

Hubbert chose the logistic and uses the rate to guess the URR. The choice of logistic is interesting and its not clear
in the least its the best and again its not clear that a better one exists given the data we have. Given that we are just doing a taylor expansion the exact shape of the curve are not important whats important or interesting is that HL works when the production is assumed to be a curve.
The examples you have given don't even behave correctly to the first taylor expansion term no wonder they blow up.

I'm only saying you need to use a production profile that can be taylor series expanded about its center point i.e it needs to look like a parabola to apply HL otherwise its junk. I don't need to do anything the work is already done and has been done for some time. You simply need to use a production profile thats reasonably close to what HL assumes.

Next since your generating data if you pick parabolas which are simple you can find one that gives a perfect match then vary the parabolas away from the perfect keeping the area under the curve or URR constant. one to see how much HL varies. Actually you can use any series of parameterized curves. The only restriction is they all have to have the same URR.

Your current work is not even close to being the right way to critique HL.

Until you integrate his work I'm not sure what the heck your doing.

What I am doing is showing case after case in which the HL failed. Do you think it might be too much to ask – given that you continue to insist that it works – for you to show me a case in which it would have worked? Thanks.

Your current work is not even close to being the right way to critique HL.

Show me the “right way.” I don’t really think that’s too much to ask. Show some cases. Plot them. Tell me the parameters that would indicate a peak to you. Don’t keep asking me to show you cases and then denigrate what you are given. Produce something yourself.

HL is reasonable if you produce max possible with regards to your URR, right?
Thats the assumption you childischly refuse to mention.
Your oilsville produces 10/5000 per year (was it?). Thats too low. Max would be 4/400 (or maybe 200 like Saudi, sounds familiar?). This is the most simple way I can put it. Change that in your spreadsheet and tell us what happens?

You sound slightly too closed to allowing other comments into your worldview at the moment. Are you always like that? Hard on debating? Do you ever yield a mm?

HL is reasonable if you produce max possible with regards to your URR, right?
Thats the assumption you childischly refuse to mention.

So, this is your response to "Show me"? You can't show me either. All of these insults and cast aspersions, and nobody can show me a case where the HL would have worked. Why is that?

Your oilsville produces 10/5000 per year (was it?). Thats too low.

How do you know what is too low? You are making unwarranted assumptions. Besides that, this wasn't the only case I modeled. What the case shows is that a flat production case - as Saudi has been for many years - will underpredict URR if production is constrained. Or do you believe that Saudi has been producing flat out for all those years?

You sound slightly too closed to allowing other comments into your worldview at the moment. Are you always like that?

Given that nobody is giving me an counter-examples to show when the HL would have worked and how you would have determined that, right now I have no reason to question my worldview. Show me a case and make me question it. I am quite open-minded, as some posters on the board who actually know me can verify.

Even though I make no claim to following the math, what I've been gleaning from this whole series of exchanges is that Hubbert noticed that the way in which oil fields were drilled and developed in an unconstrained market tended to follow a familiar pattern. He didn't know the URR, but he had enough experience to make an educated guess. That pattern has seemed to fit in other unconstrained markets.

As I see it, we don't have the info to have as good a feel for the URR of KSA, so we've seen modelers fitting the curves as if KSA is unconstrained and choosing from a fairly wide range of possible URRs.

It seems to me what Robert is doing is significantly constraining Oilsville production and then saying that because HL doesn't work in unconstrained markets, it doesn't work at all.

I have not been following this closely so forgive me if someone has already beaten this to death, but the only cases where HL should work, conceptually, are where production is only constrained by physical geology. Where the field or province operators are producing as fast as they can, or responding to smoothly rising demand (the curve shape is supposed to model the reservoir dynamics). We know this is not the case for Texas/lower 48, Saudi Arabia and Russia so I do not see why we should expect it to work there. That's why it also should not work for your thought experiments (above). If world demand rose smoothly and no one withheld production to control prices (or for whatever), we might expect it to work in the aggregate. It is not surprising that such a simple model does not work for such a complex system.

The one example you gave that was even close to reality was giving HL answers that were not too bad.

Define “not too bad.” What you will find is that once again, “not too bad” will span a huge error range.

What you have just wrote says nothing about HL it's basically garbage.

Read what WHT wrote below. He actually understood the point that I am making. Cases, hypothetical or otherwise, can show you how the HL would behave. The flat production case – hypothetical or not – shows how the HL will behave in ANY relatively flat production case (like Saudi). The rising production case shows that it can’t call peak. The rate of rise doesn’t matter. If you did some modeling yourself, you would see that. But you are still insisting that the pink unicorn is there somewhere, while saying I have do “basically garbage” in showing that it doesn’t exist.

If at this point you have some valid arguments I'm interested. I know I'm being a bit harsh but this is bogus and its public.

It’s amazing to me, then, that you won’t produce a case in which it worked. Some recognize modeling for what it is. Some know how to test a model. I do. Show me that you know how, instead of doing all the aspersion casting. Support your own argument. Look again at the last section of the essay.

RR, I think HL only works when the producer is always producing flat out. Since this never happens in real life I guess you are correct that HL can't be used to predict when peak production will occur. I think you have already proved your point.