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51 comments on The architecture of UK offshore oil production in relation to future production models

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Sam Foucher on November 26, 2006 - 8:26am Permalink | Subthread | Comments top
It's a great post. On Figure 4, you use an exponential model for the decline, a logistic curve would have been interesting also. On Fig. 9, part of the legend is missing. It's clear that we have entered the tail end of the Parabolic Fractal Law and new fields are getting inreasingly smaller.
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Euan Mearns on November 26, 2006 - 9:08am Permalink | Subthread | Parent | Comments top
Khebab - I deleted part of the legend on Figure 9 deliberately because I want to defer discussion of other production models to my next post.  I was going to do all this in one, but at 3000+ words - I thought this post was laready long enough.

RE - logistic curve - can I send you my spread sheet for some curve plotting tuition?

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Sam Foucher on November 27, 2006 - 11:47am Permalink | Subthread | Parent | Comments top
I just sent you the spreadsheet, below is the resulting chart:

The parameters of the loglets are the following:


          Loglet 1    Loglet 2
URR          7.921    16.85
Dt          10.256    19.338
Peak Date     1984.4    1998.7

Details about the Loglet analysis here.

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Sam Foucher on November 27, 2006 - 2:09pm Permalink | Subthread | Parent | Comments top
Forgot some details:
  • production number are believed to be for crude oil only (DTI).
  • the logistic growth parameters (K) for the two loglets are 42.85% and 22.72% respectively (much steeper decline than the one derived from the HL (~14%)).
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Euan Mearns on November 28, 2006 - 10:59am Permalink | Subthread | Parent | Comments top
Khebab - thanks for this.  I guess there are two messages here.  The first is that the logistic decline looks more rapid than the exponential and that my Mearns2 model may prove over-optimistic.  The second that we need to continue to be wary of data.  I think the data you have used will be for crude+condensate+NGL but may exclude the miscellaneous liquids that arrive at pipline terminals.
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Sam Foucher on November 28, 2006 - 11:17am Permalink | Subthread | Parent | Comments top
1. The decline rate of a logistic curve is proportional to the oil reserve fraction minus the cumulative production fraction(see here for details):

(dP/dt)/P=K(1-2Q/URR)=K(Reserve Fraction  - Cum. Prod. Fraction)

Consequently, the decline will be slow near the mid-point and will accelerate toward K when Q tends toward the URR.
2. If you have another dataset, I can give new estimates.

P.S.: have you received my last email from yesterday?

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51 comments on The architecture of UK offshore oil production in relation to future production models

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