le plus grand champ du koweit en déclin

[manager]

D'après ce que j'ai pu trouver

estimation officielle des réserves de Ghawar environ 200 Gb
et nous avons en production cumulée 55Gb...

200 gb - 30% = 140 Gb
/2 = 70 Gb

si on doit tenir compte du pourcentage d'extraction possible...
sachant qu'on ne parvient jamais à pomper 100%...

basons nous alors sur 40% comme pour le Koweit
- 40% = 120Gb
soit possibilité de pic à 60Gb

Tout porterait à croire que nous ne sommes pas loin du pic...
ou en plein dedans...

[lionstone]

Pup 55 dit:
http://www.peakoil.com/fortopic6772.html

describes the little calculation of how to estimate the reserves in an oil deposit. It's the following formula, which you can easily feed in to your favorite spreadsheet:

Code:


bv*fill*(n/g)*phi*(1-Sw)
---------------------------- x RF
fvf


where BV = the bulk volume
fill= the fill factor
n/g=net over gross useful fluid
phi=porosity of the source rock (which according to the above reference is about .3 for ghawar
SW=water saturation
fvf=field volume factor, which is the percent of the field which has the good source rock
RF is the recovery factor.

This is the ASPO newsletter which has some current and past estimates for Ghawar:

Ghawar Detail from ASPO

If you assume a rectangular Ghawar, at 174 miles long by 16 miles wide by 280 feet thick (per the first reference) the “bulk volume” of the field is 3.8 quadrillion barrels (converting cubic miles to cubic meters to barrels). With 33% porosity, this means only a third of this could possibly be oil, the rest is rock., but this is still a lot of oil.

I plugged numbers in for net/gross and fill factor to get the figure of 200 gb OOIP which is what ASPO claims it is. By trial and error, the values .40 for fill factor and net/gross work to get this value. A change of 5% (the difference between .40 and .45) make a difference of about 25 gb to the OOIP so what that tells you is if they are a little bit off on their estimate either way, it could make an enormous difference as to what the “reserves estimate” for this field might be. This is a major source of potential variability in the calculation and prime opportunity for fudging.

If you assume a 56% recovery factor, which according to the ASPO article is on the optimistic side, that gives the total "recoverable" volume of 112 gb. If you use ASPO's estimate of Ghawar's cumulative production to-date of about 54 gb, this means the field is not quite 50% depleted.

I agree with Nero's point above on the water issue. A field 174 miles long, one end of which is being injected with water, will not have evenly distributed water, so you have to use caution on the conclusions if you if you want to enter a water estimate. If you use 33% water saturation in the calculation, at 56% recovery rate give you a remaining field size of 74 gb, so with cumulative production of 54 gb, the field is not yet 50% depleted.

However, if you use the number you gave us above, a 61% water cut, the remaining field size is 43 gb and the field is well past midpoint. The breakeven point is about 50% water saturation. Anything above that, given the accuracy of the rest of the assumptions, will place the field in depletion.

This is obviously why the water saturation amount is so important to know.

Needless to say, the Saudis know that anybody with a spreadsheet program and an internet hookup can figure out the original reserves estimates and do these calculations, which is why they are claiming maybe 37% water saturation at this point, and keeping secret how much their production has been. Also, the Saudis have previously claimed that they can get much greater than the normal 56% recovery rate, which also remains to be seen. Also, there is no way to tell without examining the field records whether or not the fill factor and other estimates of perfection we made above are anywhere close.

Also, ASPO's estimates are not necessarily infallible either. Maybe the field is bigger and better than they thought in 1975. A little error on the fill factor or n/g ratio, as we have seen, makes a big difference to the reserves calculation.

But, now that we have a tool, if anybody can find a better source of data it would be wonderful to get it, so we can estimate the life of this old geezer.

C’est marrant comme leur forum ressemble étrangement au notre
http://www.peakoil.com/forums.html

[guino]

Oui, mais ils n'ont pas la superbe rubrique en gestation "Actions locales..."

[energy_isere]

23.8 milliards de dollars de plus par rapport au budget au Koweit !

c'est T.Breton qui va étre jaloux !

lien

Kuwait's budget surplus seen at up to $23.8b


(Reuters)

22 February 2006



KUWAIT — Kuwait is expected to realise a budget surplus of up to 6.95 billion dinars ($23.8 billion) for the fiscal year ending March 31, a leading bank said yesterday, revising upwards its forecasts due to strong oil prices.


National Bank of Kuwait (NBK) said in a report that the Gulf Opec producer was expected to earn between 13.53 billion dinars to 13.75 billion from oil export revenues — based on an estimated barrel price of $50.4 to $51.2 for Kuwaiti crude.

"Assuming that actual expenditures come between 94 per cent and 97 per cent of the budget projection, Kuwait could reap a surplus of between 6.51 billion dinars and 6.95 billion dinars," the report said, adding that the figure did not take account of a mandatory 10 per cent allocation to a state reserve fund.

"Our base-case scenario, where Kuwait export crude averages $50.9, yields a surplus of 6.73 billion dinars," it added.

The bank had in January forecast the surplus at up to 6.6 billion dinars — a downward revision from October due to a drop in the crude price.