The Top Twenty Fields: Are They in Decline?

Taking the lead from this thread over at, I thought a discussion of whether or not the top 20 fields were in decline, and then consolidating that into a reference resource would be a good idea.  Under the fold is the list they put together.
(click here to see the thread for the resources they have used to this point.  I will update as we make progress in the comment threads.)

1. Ghawar Unknown
2b. Cantarell CONFIRMED DECLINE ~14%

  1. Bolivar Coastal Unknown
  2. Safaniya-Khafji Unknown
  3. Rumaila Unknown
  4. Tengiz Unknown
  5. Ahwaz Unknown
  6. Kirkuk Decline - (smiley)
  7. Marun Unknown
  8. Gachsaran Unknown
  9. Aghajari Unknown
  10. Samotlor CONFIRMED DECLINE ~ 9%
13a.Prudhoe Bay CONFIRMED DECLINE ~11%
13b. Kashagan Unknown
  1. Abqaiq I don't know, but have you seen the cross section? It's all water!
  2. Romashkino Unknown
  3. Chicontepec Unknown
  4. Berri Unknown
  5. Zakum Unknown
  6. Manifa Unknown
  7. Faroozan-Marjan Unknown
  8. Marlim, Campos Unknown
A lot of unknowns there. Are most declines being hidden by including the water cut?
Looks a bit early for a study if 17 of the 21 fields listed have "Unknown" appended...
um, that was the point of this assemble the knowledge that people had in the comment threads.
It's a pity that this thread seems to be drawing relatively little attention, since I think it concerns an extremely important topic!  Ultimately, what this topic is relevant to is the attempt to establish an empirical database of field reserve, production, and decline rates, so as thereby to enable the scientific forecasting of depletion rates in the years following Peak.

But maybe, the inattention is ultimately due to the fact that the National Oil Companies in so many countries are being so tight-lipped with regard to this date.  I guess this is exactly what Matt Simmons is talking about in his well-known crusade for data-transparency.

Totally agree. This is THE issue right now. The big world unknown is decline, and I believe if just the top 4 or 5 are declining (over 10% of world production), this will do it for peak, given that the smaller fields can't make up for them and besides deplete rapidly themselves.

I think the issue is we don't have the data, which points out the problem.

yes, but is this all we have?  it seems like we have mentioned a couple of these other fields...but I'll be darned if I can find em.
OK, here's from a link I posted below:
Similar but not the same as in the intro.
Simmon's "Twilight" book has a list of top 33 fields in the world and their production in 1971 and 2000 (when available). I put a # by the ones showing a decrease using his table, or that show a decrease from 1970s to 2000 by comparing 2 tables in his book. Most don't have data at both time points to compare.

I put a star by the fields we know are peaking now, a question by ones we think are peaking:

Top 18 Giant Fields

Field Name        Country             Discovery year             Range of URR [GB]

Ghawar          Saudi Arabia                 1948                             66-100 ?
Burgan          Greater Kuwait              1938                             32-60 *
Safaniya        Saudi Arabia                  1951                              21-36 #
Bolivar          Coastal Venezuela         1917                              14-36
Berri             Saudi Arabia                  1964                              10-25 #
Rumalia N&S Iraq                               1953                              22
Zakum         Abu Dhabi                      1964                              17-21
Cantarell      Mexico                           1976                              11-20 *
Manifa         Saudi Arabia                   1957                              17
Kirkuk          Iraq                                1927                              16 #
Gashsaran    Iran                                1928                             12-15
Abqaiq         Saudi Arabia                  1941                              10-15 #
Ahwaz          Iran                               1958                              13-15
Marun          Iran                                1963                              12-14
Samotlor      Russia                            1961                              6-14 *
Agha Jari      Iran                                1937                              6-14
Zuluf            Saudi Arabia                   1965                             12-14
Prudhoe Bay Alaska                            1969                             13 *

Other than what I've noted, after much searching (mostl Google), it seems very difficult to get specific production rates, esp from Iran. However, just glancing down the list it is clear that declining fields are not an exception in this group.

The recent Saudi announcement about a mature fields declining by 8% sounds like Gwahar is in decline by about that much now or shortly in the future. It's interesting how high the decline rates are for the ones that are confirmed. A lot of drilling is going to be needed to replace that oil every year.
Reuters:  Qatar says OPEC can do nothing about high oil price


"Oil prices have risen more than 20 percent since mid-February, despite sizable U.S. crude inventories, as geo-political fears compounded fundamental worries that refiners might struggle to make enough gasoline for the summer driving season."

Guess what else happened in mid-February?  Total net US imports started falling.   The following numbers are weekly, not four week running averages.  The week ending 2/10/06 showed average daily net oil imports of 13,396,000 bpd.  Seven of the subsequent weeks have shown declines.  The most current weekly data show 11,634,000 bpd.  This is a decline of 13.2%.   (The same period last year showed about a 3.7% decline.)

Looking at a slightly bigger picture, 12/30/05 to 4/7/06 (four week running average) we saw a decline of 8.7% (versus an increase in imports for the same time period last year).

Note that we don't know what percentage of crude oil inventories consists of heavy, sour crude.  Also, total product inventories are only up 2.9% year over year.   But fundamentally, what do you expect to see at peak production?  I expect to see peak everything, followed by a permanent and irreversible decline in conventional oil production.  Note that the EIA data show that world crude + condensate production was down by close to 500,000 bpd from 12/05 to 1/06 (versus an increase last year), following the all time record high number in December.  What did Deffeyes have to say about December?

If refiners don't need the imports, why are they bidding up the price?

"Guess what else happened in mid-February?  Total net US imports started falling."

Might imports be falling because inventories are high?
Seems like the price is whatever the market will bear.

Note that total net oil imports should be total net petroleum (crude + product) imports.
Based on how I interpret your line of thinking, you are saying that the price of oil is high even though we have a large buildup in inventories because we have a lot of heavy, sour crude and not enough light, sweet oil.  The inventory number represents the total oil supplies in the country, but it doesn't reflect the light, sweet oil shortage that is going on.  Correct?

This makes sense to me.  However, I would think that you would see a price difference between the different grades of oil.  Light, sweet should be priced much higher than historic norms when looking at the difference in price between light, sweet and heavy, sour.  

So, I downloaded oil price data on SA light and SA heavy between 1978 and April 2006.

Year    LIGHT OIL    HEAVY OIL    Diff    % Diff
1978-Jan    12.70    12.02    0.68    5.6572
  1989-Jan    13.15    11.90    1.25    10.5042
  1990-Jan    18.40    17.15    1.25    7.2886
  1991-Jan    24.00    20.00    4.00    20.0000
  1992-Jan    15.90    13.15    2.75    20.9125
  1993-Jan    16.80    14.40    2.40    16.6667
  1994-Jan    12.40    10.10    2.30    22.7723
  1995-Jan    16.63    15.13    1.50    9.9141
  1996-Jan    18.20    17.05    1.15    6.7449
  1997-Jan    22.98    21.08    1.90    9.0133
  1997-Feb    21.55    19.65    1.90    9.6692
  1997-Mar    18.65    16.75    1.90    11.3433
  1997-Apr    18.33    16.48    1.85    11.2257
  1997-May    18.25    16.40    1.85    11.2805
  1997-Jun    18.92    17.17    1.75    10.1922
  1997-Jul    18.15    16.40    1.75    10.6707
  1997-Aug    18.27    16.67    1.60    9.5981
  1997-Sep    17.88    16.77    1.11    6.6190
  1997-Oct    19.13    18.03    1.10    6.1009
  1997-Nov    19.13    18.23    0.90    4.9369
  1997-Dec    17.65    16.15    1.50    9.2879
  1998-Jan    15.50    14.00    1.50    10.7143
  1998-Feb    13.40    11.70    1.70    14.5299
  1998-Mar    11.95    10.05    1.90    18.9055
  1998-Apr    12.60    10.70    1.90    17.7570
  1998-May    12.48    10.83    1.65    15.2355
  1998-Jun    12.68    11.28    1.40    12.4113
  1998-Jul    11.75    10.35    1.40    13.5266
  1998-Aug    12.55    11.65    0.90    7.7253
  1998-Sep    12.55    11.55    1.00    8.6580
  1998-Oct    14.03    13.03    1.00    7.6746
  1998-Nov    12.45    11.60    0.85    7.3276
  1998-Dec    9.95    9.20    0.75    8.1522
  1999-Jan    10.03    9.28    0.75    8.0819
  1999-Feb    10.53    9.68    0.85    8.7810
  1999-Mar    10.18    9.38    0.80    8.5288
  1999-Apr    13.83    13.03    0.80    6.1397
  1999-May    16.53    15.53    1.00    6.4392
  1999-Jun    14.40    13.50    0.90    6.6667
  1999-Jul    16.10    15.20    0.90    5.9211
  1999-Aug    18.58    17.43    1.15    6.5978
  1999-Sep    20.38    19.33    1.05    5.4320
  1999-Oct    23.00    21.95    1.05    4.7836
  1999-Nov    21.93    21.08    0.85    4.0323
  1999-Dec    24.23    23.38    0.85    3.6356
  2000-Jan    23.45    22.10    1.35    6.1086
  2000-Feb    25.28    23.43    1.85    7.8959
  2000-Mar    25.30    23.45    1.85    7.8891
  2000-Apr    23.88    22.93    0.95    4.1430
  2000-May    24.20    23.20    1.00    4.3103
  2000-Jun    27.10    26.10    1.00    3.8314
  2000-Jul    28.13    26.93    1.20    4.4560
  2000-Aug    24.88    23.28    1.60    6.8729
  2000-Sep            0.00   
  2000-Oct    29.15    27.05    2.10    7.7634
  2000-Nov    29.68    27.58    2.10    7.6142
  2000-Dec    29.08    27.33    1.75    6.4032
  2001-Jan    20.90    19.40    1.50    7.7320
  2001-Feb    23.48    21.98    1.50    6.8244
  2001-Mar    23.83    22.33    1.50    6.7174
  2001-Apr    23.20    22.15    1.05    4.7404
  2001-May    25.35    24.15    1.20    4.9689
  2001-Jun    27.55    26.35    1.20    4.5541
  2001-Jul    24.23    22.63    1.60    7.0703
  2001-Aug    24.33    22.73    1.60    7.0392
  2001-Sep    24.70    23.60    1.10    4.6610
  2001-Oct    20.83    20.08    0.75    3.7351
  2001-Nov    19.08    18.33    0.75    4.0917
  2001-Dec    18.33    17.58    0.75    4.2662
  2002-Jan    18.90    18.15    0.75    4.1322
  2002-Feb    17.39    16.54    0.85    5.1391
  2002-Mar    18.86    18.01    0.85    4.7196
  2002-Apr    24.58    24.08    0.50    2.0764
  2002-May    23.35    22.35    1.00    4.4743
  2002-Jun    21.57    20.82    0.75    3.6023
  2002-Jul    22.62    21.97    0.65    2.9586
  2002-Aug    23.02    22.07    0.95    4.3045
  2002-Sep    24.96    23.96    1.00    4.1736
  2002-Oct    26.63    25.63    1.00    3.9017
  2002-Nov    23.36    22.36    1.00    4.4723
  2002-Dec    23.19    21.89    1.30    5.9388
  2003-Jan    27.39    25.69    1.70    6.6174
  2003-Feb    28.73    27.03    1.70    6.2893
  2003-Mar    31.72    29.92    1.80    6.0160
  2003-Apr    24.50    21.25    3.25    15.2941
  2003-May    20.27    18.32    1.95    10.6441
  2003-Jun    23.52    22.27    1.25    5.6129
  2003-Jul    25.39    24.34    1.05    4.3139
  2003-Aug    25.58    24.83    0.75    3.0205
  2003-Sep    26.31    25.31    1.00    3.9510
  2003-Oct    25.54    24.14    1.40    5.7995
  2003-Nov    25.75    24.40    1.35    5.5328
  2003-Dec    26.17    24.47    1.70    6.9473
  2004-Jan    27.08    25.38    1.70    6.6982
  2004-Feb    26.31    23.36    2.95    12.6284
  2004-Mar    29.55    26.80    2.75    10.2612
  2004-Apr    28.68    26.23    2.45    9.3404
  2004-May    32.51    29.66    2.85    9.6089
  2004-Jun    33.77    30.62    3.15    10.2874
  2004-Jul    31.72    28.02    3.70    13.2049
  2004-Aug    36.17    32.67    3.50    10.7132
  2004-Sep    37.68    33.48    4.20    12.5448
  2004-Oct    40.84    36.39    4.45    12.2286
  2004-Nov    41.23    35.48    5.75    16.2063
  2004-Dec    36.87    30.12    6.75    22.4104
  2005-Jan    34.05    27.95    6.10    21.8247
  2005-Feb    38.05    33.35    4.70    14.0930
  2005-Mar    44.70    39.55    5.15    13.0215
  2005-Apr    48.20    42.80    5.40    12.6168
  2005-May    44.48    38.98    5.50    14.1098
  2005-Jun    45.96    41.16    4.80    11.6618
  2005-Jul    52.77    48.02    4.75    9.8917
  2005-Aug    54.32    48.87    5.45    11.1520
  2005-Sep    62.10    56.75    5.35    9.4273
  2005-Oct    54.71    48.51    6.20    12.7809
  2005-Nov    52.31    46.06    6.25    13.5693
  2005-Dec    49.00    43.15    5.85    13.5574
  2006-Jan    55.01    50.41    4.60    9.1252
  2006-Feb    59.56    54.31    5.25    9.6667
  2006-Mar    56.71    51.76    4.95    9.5634
  2006-Apr    61.04    56.29    4.75    8.4384

The first two columns are light and heavy prices, respectively.  The next two are the difference and % difference.  This data shows that, since 1978 we have had quite a bit of fluctuation in price.  The price difference between heavy and light has grown recently, but it looks like we had similar price differences back in 1998 without an imminent oil peak.  

So, I'm not sure why the price of oil is going up based on this data.  Comments?

A very worthwhile study. Don't have time to work on this right now, but I think it would be very helpful to put in date of discovery and recent production stats. Most important right now is not just original reserves but the production they contribute currently. For example, China's largest field Daqing is not on the list but should be, and it peaked in 2003, I believe.

Looks like Daqing dropped below 1 mbpd starting in 2003-2004 after decades of production over that figure.
Re:  Top 20

It looks like they left off Daqing, which is a confirmed decline.  

As I understand it, there are four fields that are currently producing about one mbpd or more:  Ghawar; Cantarell; Burgan and Daqing.  We know that three of the four are declining, and it is very likely that Ghawar is now declining.  

Note that it takes lots of smaller fields to make up for declines in fields producing about 10 mbpd.  

The two "cleanest" HL case histories we have are the Lower 48 and the North Sea.  The two principal constraints on production were:  (1)  they would not produce oil at a loss and (2)  fields were generally produced at a rate which would not damage the reservoirs.   There were no substantial political problems or constraints on production.

The Lower 48 peaked at slightly less than 50% (at 49%) and the North Sea peaked at slightly over 50% (52%).  In other words, slightly less than 50% to slightly more than 50%.  These were both for crude + condensate   Deffeyes estimated that we hit the crude + condensate 50% of Qt mark worldwide in mid-December.  The highest crude + condensate EIA number on record was for December, followed promptly by about a 500,000 bpd drop in January.

In the article that Khebab and I coauthored that was published on March 6, 2006, we had following statement:

"A critical point to keep in mind is that an exporter can only export what is left after domestic consumption is satisfied. Consider a simple example, a country producing 2.0 mbpd, consuming 1.0 mbpd and therefore exporting 1.0 mbpd. Let's assume a 25% drop in production over a six year period (which we have seen in the North Sea, which by the way peaked at 52% of Qt) and let's assume a 10% increase in domestic consumption. Production would be 1.5 mbpd. Consumption would be 1.1 mbpd. Net exports would be production (1.5 mbpd) less consumption (1.1 mbpd) = 0.4 mbpd. Therefore, because of a 25% drop in production and because of a 10% increase in domestic consumption, net oil exports from our hypothetical net exporter dropped by 60%, from 1.0 mbpd to 0.4 mbpd, over a six year period.

We are deeply concerned that the world is probably facing an imminent and catastrophic collapse in net oil export capacity because of declining production and increasing domestic consumption in the top exporting countries."

From 2/10/06 to 4/7/06, total net oil imports into the US dropped 13.2%, which corresponded to a 20% increase in oil prices.

Consider the simple math.  If Deffeyes is correct, at current rates of consumption, by the time that a first grader, entering the first grade this September, 2006, is ready for the fifth grade in September, 2010, we will have used more than 10% of all remaining conventional crude + condensate reserves.

So lay it down for the layman, westexas.  You seem to be fairly supportive of Deffeyes' "December 16th" call, and your predictions of steep drops in oil imports to the US since around that time have apparently so far been correct.

Are you saying that the S has HTF?

There is always the possibility of post hoc ergo proctor hoc (just because "B" follows "A" doesn't mean that "B" is caused by, or related to, "A."); however, the HL method that I am using has a proven track record.

Having said that, IMO the SHTF.  

I think that we should all practice ELF.

Economize--try to reduce your spending to 50% of current income.  Assume that you just got a 50% pay cut. What actions would you then take?

Localize--try to reduce the distance between home and work to as close to zero as possible.  Assume that gasoline costs about the same as Norway, $7 per gallon or more.  What actions would you then take?

Produce--look into becoming or affiliating yourself with a net food producer or net energy producer.  Or at least try to work with a company that provides basic needs, instead of "wants."  Today, the majority of Americans live off the discretionary income of other Americans.  Assume that our discretionary income drops by 50%, what industries would you want to be in?

We need to radically rethink the kinds of careers that young people should go into, and parents need to think very hard about going into debt to unleash yet another law school graduate on the country.  

Thanks for your insightful analysis and advice.  Have been ElFing for some time now-- short drive to work in hybrid purchased with cash, work in a relatively recession-proof firm (though I'll have to re-evaluate this with the long term in mind), have been vege gardening for several years, am on CSA plan with a large local farm, etc.

More than anything else I worry about the same things as many of my generation: how will society in general react/respond, and how will my childrens' future look.

It's fascinating to map some of the indicators chronicled by you and others here to occurrances in the world.  I accept the risk of beating the dead horse when I say, "we live in interesting times."

we wont see problems until crude stocks begin to decline. It makes sense for imports to decline if refineries cant use more crude - they might be choking on the stuff right now in part because not all refineries are back on line. Price can be high when the use refuses to take as much crude as before not necessarily because of geopolitical concerns, which naturally are big right now, but because the rest of the world is buying, not least the new kids in the east. If price were based simply on the level of crude stocks, price would be much lower right now.
"we wont see problems until crude stocks begin to decline"

Let's assume that 100% of crude oil stocks consist of heavy, sour crude--which cannot be run though a refinery that will handle only light, sweet crude. Would we then have a problem?

My point is that we have no idea what percentage of current crude inventories consists of heavy, sour.  No one tracks it.

When the government is not putting oil in the SPR, there is only one market for light, sweet crude oil:  refineries.

If refineries did not need the oil, why would they have bid up the price by 20% since mid-February?

Look at the trends in the past two months:  total petroleum imports down by 13%, light, sweet crude oil prices up by 20%.  This suggests to me that we have only begun to see the price increases.

PO may be coming soon, but recent market behavior can be explained without it. (World) prices are high because of the iranian confrontation; nobody wants to be without crude if TSHTF. OTOH, (US) crude stocks are very high on account of K/R disruptions, so (US) users cannot accept more crude at this time, sending crude elsewhere, maybe from the persian gulf to china/india, whose refineries are not suffering from similar problems. Note that this theory explains the poor market for long haul tankers - shorter shipping distance reduces the need.
Iranian leaders find the confrontation usefully rallies the population to their side; nevertheless, if they agreed to allow russia to enrich their fuel, crude would fall, maybe back to the opec floor of around 55-60.
It is true that commercial stocks would be 15mmb lower if loans from teh spr were repaid, and gasoline stocks would be around 2mmb lower if loans from europe were repaid.
These seem to be the top twenty fields in terms of proven reserves and I can't find an actual source for the data over at

What I'd prefer to see is the top twenty fields in terms of daily production with an analysis of depletion. That's obviously not the same list.

In any case, just for our amusement, I refer you to Qatar sees no OPEC ouput cut in '06 if demand holds in which we learn

OPEC is unlikely to cut oil output for the rest of 2006 if global demand holds steady and with prices near $70 a barrel, Qatar's oil minister said on Monday.

Abdullah al-Attiyah also said the Organisation of the Petroleum Exporting Countries (OPEC), already pumping at near-maximum capacity, was powerless to help cool oil prices, which have risen more than 20 percent since mid-February.

"With demand at this level, I think we will keep the output the same all year," Attiyah told Reuters.

But here's the kicker
"On production there is nothing we can do. We are already producing at maximum output," he said. "There is no shortage in supply."
Laugh or cry? Perhaps Abdullah al-Attiyah was making a joke?

He looks like the kind of guy who has a good sense of humor.

The Saudi ambassador just said the same thing about Saudi production.  Someone asked him what SA would do if conflict with Iran disrupted oil production.  He replied there was nothing they could do, because they are already producing at maximum.

However, he did promise increased production in a few years, from new projects/infrastructure.

The Romashkino field is probably in decline (the production started in 1948, URR~16Gb), decline around 16%?

This is a little confusing - Cantarell peaked about twice what they claim for field peak. Even though the paper was published in 2004, it seems the author didn't realize the discrepancy already observed. It actually had 2 peaks, one before and one after N2 injection started, as I recall. How does his study address this? Am I missing something?
Their time serie for Cantarell is a little bit old (1996).
Aha!  With all those many "unknowns," we have exactly what was missing from Chris Skrebowski's latest "Megaprojects" updates.  Stuart was totally right to critique Skrebowski for Skrebowski's prognostications of future growth without taking any substantive account of this "decline" part of the equation.

But to really do a comprehensive job, one would have to take into account much more than the top 20 fields.  Probably a comprehensive treatment that is adequate to complement Skrebowski's "Megaproject" studies in order to make it a somewhat accurate instrument of prediction would be the top 200 fields or so.  (Does that sound about right?  How many "unknowns" would there be in that expanded list?)

[Mr Skrebowski:  If you're a TOD reader, sorry to tear into you like this.  Please know that I personally do value your work very highly - as I'm sure most if not all TOD participants and readers do.]

Here's the link to the pertinent "Megaprojects Critique" thread:

But to really do a comprehensive job, one would have to take into account much more than the top 20 fields.

According to Simmons:

The analysis should look at fields with production > 100 kbpd (116 fields) which are producing almost half of the world production.

The figure from Simmons is brilliant.

However when was it made 2002 or 2003?

Probably necessary to do an update with 2005 figures.

Could reduce the number of fields.

Ah well, with oil hovering at around
$72 a barrel, owning any oil well
has probably never been more lucrative.
And $70+ is just the start.
Very worthwhile link on this topic, but still doesn't give detailed current production data on the giants:

Chicontepec is an example of where the elephant was found late.  First discoveries in 1926, a major field was found in 1973.  Oil is too heavy to be attractive till now.  Fox recently announced Pemex plans to spend US $37 billion to get production up to 1 million b/day in twenty years.
Thanks for the comment, although I don't see Fox as a fount of credibility.
Manifa oil has a limited market due to high vanadium levels that poison catalysts.  Perhaps Saudi dilutes it with other fields with similar high garvity or ??

Anyway, quite limited production to date from reserves of 11 Gb.  Not one going into decline soon !  A major uptick if Saudis build refinery (classical fractional distillation ?) to process Manifa crude.

Oil Power Pyramid