Ghawar flushed out some 6.5 MMbbl/d in the 70's, 5 now. But of course, aramco says it's a controlled production limitation to extend reserves life, not a decline.




Yep. Accoprding to some sources, the three main reservoirs will be filled with water by 2010-12, and production will crash.
The field was somewhat damaged by the uncontrolled pressure drop in 1991 (when the iraqis set fire to the wells)



Yep. It's a unique field, it's reservoir structure is a meteoritic crateer, probably the meteor that killed dinos, so it took everyone by surprise.
N2 injection worked great to double production, but didn't increase the ultimately recoverable oil volume. It just depleted the field increadibly fast.



Massive water injection and infill drilling to keep production roughly constant. Note bolivar coastal is not a sinle field, but a cluster of fields, the first of which was found in 1917.



Was damaged by inadequate exploitation at the end of hussein's reign. Kirkuk and Rumaila, together, gave 87% (!) of cumulative iraqi production to date, they are severely depleted but other iraqi fields can provide - it seems iraq have 4 fields of more that 5 Gb each that have been little or not exploited : East Baghdad, Majnoon, Um Nahr and West Qurna. They all should be added to this list and would make it look a bit less gloomish.



Yep, but it's very high-sulfur oil.



64% it cumultive decline since peak i guess. The five largest field in Khuzestan (SW iran) each peaked near, at, or slightly above 1 Mb/d (not simultaneously). Now the collectively produce 1100 kb/d. The Iranians are building a HUGE gas pipeline to bring natural gas for the North Dome/South Pars fdield there, for enhanced oil recovery. But this will consume immense amounts of gas, through much of it may be extracted again later (after the end of large scale oil production).



Kirkuk was damaged by bad practises in the recent years, even more than rumaila. They reinjected gas-stripped crude oil, because they needed associatedc gas for power production but couldn't export the crude. They injected too much water, and pumped oil too hard, creating early water breakthoughs at some points. They even reinjected excess refinery products !
These bad pratise may have damaged the field forever.



same as ahwaz.

>>> 11b Shaybay
>>> 11c Manifa

these saudi fields should rank here, they have some 15 Gb each.
Manifa is shut in and have not been much exploited. However, its vanadium content make its oil very difficult to use.
Shaybah is producing 500 kd/d since 1998. It could maintain this plateau untill 2050. But they will double the output, they need to compensate decline in other fields.



It is producing 300 kb/b, 10 times less than in the 80's. But it's still the largest producing russian field. Note it was overpumped by the soviets.



450 kb/j, vs 1600 in the 80's. Dying. May have a second life as gas field, the gas dome have some 30TCF.



Yes, not yet exploited, perharps the largest intact conventionnal oil field in the world. It should produce 1200 kb/d in 2015, since burgan will probably have decline a lot before that, it may then be the 2nd largest producing field in the world, after Ghawar.
Not easy to exploit : very deep, high pressure, high sulfure content.



73% of original reserves in this field are gonr, accordint to aramco itself. Production is rouglhly half its peak.



Yes. Discovered in 1942. Dying.



Very little production to date. But it's very difficult oil, very heavy, at the fringe of conventionnal oil.



In decline, according to simmons, it may end up been exploited as a gas field.



Additionnal production possible, according to national oil company



Shut-in. additionnal production likely. lots of vanadium.



Yep. Deepwater. Deepwater fields are not huge (only 3 or 4 exceed 1 billion barrels) but are exploited at insane depletion rates, often more than 10%.
So while deepwater basins add lot of production in the near term, they will bring huge decline in the future - worst than the north sea.

You're right for these fields, although plutonio is not that large (~1Gb) - but it's a good exemple of what is making today boom in West Africa production : 'small giants', most of them in deepwater, that offer good quality oil, but are exploited with vey high depletion rates.
They provide lots of extra production, Kizomba (in fact a complex, several fields) in Angola will plateau at 750 kb/d. But they will start to declinf after only a few years. And most of them will be ocmpletely gone before 2020.

Yibal is a good exemple of the frankestaniendeclined rates that happens sometims with modern production technique : hz well and so on.

Qatif is one of the fields the saudis shut in and are now redevelopping. Khurais is bigger i think.

Daqing is indeed a very large field, now in decline.

Your should also add :
HASSI MESSAOUD, algeria, 9Gb, discovered in 1956. The largest oil field in africa.
THUNDER HORSE, as another exemple of the deepwater boom.
EAST TEXAS : a super-giant (6Gb) found in the 30's, now almost 100% depleted.

There are about 650 giant oil fields the worlds - ie fields that exceed 500 Mboe of oil+gas (3Tcf for gas-only fields).

For Cantarell, 35 Gb is OOIP (originally oil in place), recoverable ultimates (produced already + reserves) are 17 Gb (50% - good recovery rate).

For Marlin, rezserves are around 2 Gb. I think the "10-14 Gb" refers to the whole campos basins, where most of large brazilian fields are located.

Brazil and Angola arez the biggest oil producers in the southern hemisphere. It's noteworthy than the southern hemisphere have only 5 to 10% of world's initial oil reserves !

That's some fantastic info Raminagrobis. I do however have a few questions before I make an update:

1a. It has been suggested to include additional fields on the list. However, I don't know what order they should be in (largest to smallest). Where do the new fields fit on the list?

1b. The original list was supposed to be the top 20 fields. It's currently at 23. Since the purpose of the list is not to be a definitive resource, but rather a quick reference, where should the cutoff be?

2. In regards to #7 Ahwaz. I calculated the 64% decline from the peak production of 250kb/d to the current 160kb/d. Would 31% be more accurate, based on the projected 60kb/d 2 years from now?

3. In regard to #1 Ghawar. Based on your figure of 6.5Mb/d in the 70's and the current 4.5Mb/d, that's roughly a 30% total decline over 30 years. Of course, the Saudis would never admit to any decline in Ghawar, so would a rating of "suspected decline 1%" be appropriate?

4. Can you supply a decline figure for Kirkuk?

5. Would it be fair to say that Abqaiq is producing at a near-constant rate, but is set for massive declines in the very near future? There was a cross section posted here some time ago, and it showed the water to be as high as 2300 feet and a very thin oil layer.


Made the following changes:

Bolivar - Level Production
Romashkino - CONFIRMED DECLINE (Rate?)
Chicontepec - ADDITIONAL PRODUCTION POSSIBLE
Berri - CONFIRMED DECLINE (Rate?)
Zakum - ADDITIONAL PRODUCTION POSSIBLE
Manifa - Shut in ADDITIONAL PRODUCTION POSSIBLE

Here is the source for Kirkuk



http://www.mees.com/postedarticles/ener ... n02a01.htm

Couple basic observations:

1. Half the top 20 are in decline. Given the significant % of oil that these fields provide, just another indication that we are close to peak.

2. In some ways this examination just highlights how difficult it is to get some basic information due to the fact that many of the largest remaining fields are run by state run compaies, etc.

1994 field list in order of size, cumulative total of reserves of these 100 fields was 852 billion barrels back in 1993.

Rank Field Name Country Discovery year
1 Ghawar(Total) S. Arabia 1948
2 Greater.Burgan Kuwait 1938
3 Bolivar Coastal Venezuela 1926
4 Rumaila North & South Iraq 1953
5 Safaniya S. Arabia 1951
6 Kirkuk Iraq 1927
7 Samotlor C.I.S. 1965
8 Zakum UAE-Abu Dhabi 1964
9 East Baghdad Iraq 1979
10 Manifa S. Arabia 1957
11 Gachsaran Iran 1928
12 Abqaiq S. Arabia 1941
13 Ahwaz Iran 1958
14 Romashinko C.I.S. 1948
15 Cantarell Complexx Mexico 1976
16 Marun Iran 1963
17 Zuluf S. Arabia 1965
18 Berri S. Arabia 1964
19 Agha Jari Iran 1936
20 Daqing China 1959
21 Khurais Iran 1957
21 Prudhoe Bay U.S.A. 1967
22 Bu Hasa UAE-Abu Dhabi 1962
23 West Qurna Iraq 1973
24 Fedor-Surgutskoye C.I.S. 1962
25 Hassi Messaoud Algeria 1956
26 Kafhji N.Z. 1959
27 Raudhatain Kuwait 1955
29 Krasnoleninskoye C.I.S. 1962
30 Bab UAE-Abu Dhabi 1963
31 Abu Sa'fah S. Arabia 1963
32 Zubair Iraq 1948
33 Ust-BaIyk.-Mamontoyskoye C.I.S. 1961
34 Shaybah S. Arabia 1968
35 Majnoon Iraq 1977
36 Asab UAE-Abu Dhabi 1965
37 Tengiz Kazakhstan 1979
38 Qatif S. Arabia 1945
39 Pravdinks-Salym C.I.S. 1964
40 Marlim Brazil 1985
41 Umm shaif Of 1958
42 Panshan (Liaho Complex) China 1964
43 East Texas ON 1930
44 Sabriya Kuwait 1957
45 Bai Hassan Iraq 1953
46 Dukhan Qatar 1940
47 Pokachevsko-Uryevskoye C.I.S. 1971
48 Sarir (065-C) Libya 1961
49 Minas Indonesia 1944
50 Carito Venezuela 1988
51 Khursaniyah S. Arabia 1956
52 Marjan S. Arabia 1967
53 Duri Indonesia 1941
54 Rag-E-Safid Iran 1963
55 Arlanskoye C.I.S. 1955
56 Bibi Hakimeh Iran 1961
57 Statfjord Norway 1974
58 Uzen'skoye (S Mangyshlak-U) Kazakhstan 1961
59 Nahr Umr Iraq 1948
60 Abkalun Mexico 1979
61 Gialo (059-E) Libya 1961
62 Minagish Kuwait 1959
63 Tevlin-Konilorskoye C.I.S. 1971
64 Furrial-Musipan Venezuela 1986
65 Karamay-Complex China 1955
66 Umm Gudair Kuwait 1962
67 Priobskoye C.I.S. 1982
68 Wafra N.Z. 1953
69 Russkoye C.I.S. 1968
70 Vatyegan C.I.S. 1971
71 Wilmington U.S.A. 1932
72 Lyantor C.I.S. 1966
73 Midway-Sunset U.S.A. 1894
74 Jambur Iraq 1954
75 Forties U.K. 1970
76 Tuymazy(Aleksondrovskoye) C.I.S. 1937
77 Foroozan Iran 1966
78 Balakhano-Sobundlino-Ramon Azerbaydzhan 1871
79 Bombay India 1974
80 Renqiu China 1975
81 Ekofisk Norway 1969
82 Subba Iraq 1978
83 Nasser (006-C/41/4k) Libya 1959
84 Varyegan C.I.S. 1968
85 Karanj Iran 1963
86 Cerro Negro-Faja 29 Venezuela 1980
87 Hawtah S. Arabia 1989
88 Ku Mexico 1979
89 Paris Iran 1964
90 Harmaliyah S. Arabia 1971
91 Amal (012-8/E/N/R) Libya 1959
92 Lamar Venezuela 1958
93 Shuguang (liaohe CoI1'f)Iex) China 1975
94 Kern River U.S.A 1899
95 Augilo-Nafoora (102-Oj051- Libya 1965
96 Buzurgan Iraq 1969
97 Brent U.K. 1961
98 Yates U.S.A. 1926
99 Wasson U.SA 1936
100 Povkhovskoye C.I.S. 1972

There are some differences here with what WoodMackenzie has assessed. As background WoodMac takes production history, reserve assesments and evaluates them in terms of existing infrastructure and future development plans that have been approved. Their reserve numbers for P + P tend to be more conservative than IHS Energy simply because they lump a lot of potential reserves into a category they call "technical reserves" which means further investment is needed to bring them on stream. Anyways:

Ahwaz field has two components, the Asmari development and the Bangestan development which came on stream much later. The Asmari portion started to decline in 2000 from 954 KBPD and is projected to continue on a 5%/annum decline according to WoodMac. They have 41 GB remaining of URR. In the Bangestan where there is only 4 GB remaining of URR production is expected to ramp up from the current 209 KBPD to 480 KBPD by 2010.

At Ghawar WoodMac shows average daily prod that has bounced back and forth from 4.9 MMBD to 5.3 MMBPD since 2000. WoodMac reserves are 130 GB P+P compared to IHS Energy ~140 GB P+P. IHS suggests 3P reserves of 185 GB. There is no decline apparent in the production curve to this point in time. Based on their most conservative estimate WoodMac suggests decline won't happen until after 2010.

For Kirkuk WoodMac suggests ~ 5GB remaining. Production ramped up from 500 KBPD in '95 to 700 KBPD in the late nineties and maintained that rate until 2001. Production dropped rapidly to ~250 KBPD from '03 through '05 but this was due entirely to closure of the export line to Ceyhan. According to WoodMac actual production today is back to 500 KBPD but half of that production is being degassed and reinjected (so a net number of 250 KBPD). WoodMac believes that eventually planned infill wells will be drilled (this was one of the fields multinationals wanted access to) and the Kurmala dome will be drilled up. They suggest production will ramp up from 2008 - 2010 to ~800 KBPD and then decline rapidly from 2015 onwards.

Abaqiq suffers badly from that picture you reference. To the layman it looks bad, to a petroleum engineer it looks like an excellent simulation of a water flood that is working exceptionally well (which it is). Note that ultimate recovery factor in this field is projected to be 72% which is really spectacular. WoodMac suggests there is a sustainable capacity at Abaqiq of 600 KBPD. They have it being produced at a constant rate of 480 KBPD until 2012 when it starts to decline.

1. Expanded list to include the top 100 fields. Focus is still on the top 20, but any information can be useful
2. Upgraded Abqaiq to "Level production"
3. Added source for Kirkuk
4. Upgraded Qatif to Shut in, additional production possible
5. Downgraded Daqing to CONFIRMED DECLINE (Rate?)
6. Upgraded Ghawar to "Level production"
7. Added home country of each field
8. Moved Kashagan, Chicontepec and Faroozan-Marjan to "orphaned fields" because I don't know where they fit in the new list

To Do:

Colour code entries based on oil types. Suggested categories:

Light Sweet (Above what specific gravity? Below what sulfur content?)
Light Sour
Heavy Sweet
Heavy Sour
Extra Heavy (Anything equal to or less than 10° API?)

Thanks for all your collaboration and hard work Twister and everyone. This is exactly the kind of info I was curious about. I do appreciate it.

Kashagan was discovered in 2000, I think the other two were also discovered after 1994 so they don't show up in the 100 field list.

Updated the entry for Daqing to include decline rate and a link to the cited source.

Perhaps also extra light, super light and ultralight, if any of the majors produce such oils. And it is sour if it has 1.5% sulphur or more, so less than 1.5% sulphur should be sweet since there is no intermediate grade.