<DrumBeat: January 3, 2008 The Oil Drum TWIP - This Week In Petroleum (1-3-08)>

43 comments on Saudi Arabia: An Attempt to Link Oil Discoveries, Proven Reserves and Production Data

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Euan Mearns on January 3, 2008 - 4:02pm Permalink | Subthread | Parent | Comments top

Of course, Saudi Aramco is claiming that horizontal wells have boosted the recoverable reserves in the field, but that is what Shell though they had done at the Yibal Field, where they were expanding their surface facilities to handle an expected increase in oil production, when they were hit with an unexpected flood of new water..

Jeffrey, would you care to explain to our readers the difference between:

1) a horizontal well drilled into a thinned oil column in good quality reservoir late on in field life that is intended to lower water cut (e.g. N Ain Dar), and

2) a horizontal well drilled into a poor quality reservoir that may be impossible to develop using vertical wells (e.g. Haradh)

and then say if you think it is reasonable or not for Aramco to expand reserves of Ghawar in the latter case?

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westexas on January 3, 2008 - 4:46pm Permalink | Subthread | Parent | Comments top

Of course there is some improvement in URR in the case of #2, but what will be the increase in URR from the entire Ghawar complex as Saudi Aramco is forced to produce a "poor quality reservoir?"

Why would Saudi Arabia be bothering with a poor quality reservoir if they didn't have to?

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JoulesBurn on January 3, 2008 - 6:01pm Permalink | Subthread | Parent | Comments top

Estimates of URR involve a certain set of assumptions regarding the field itself (reservoir volume, perm., porosity, original water, residual oil), the technology to be used, and the developmental strategy. Few of those are known very well at the onset.

If the reservoir is well behaved (i.e. horizontal and vertical equilibrium is maintained), one would think it wouldn't matter if one used vertical or horizontal wells. Just phase out peripheral wells which are watering out, drill new ones updip, and drain it until all that's left is the residual oil. To get beyond that, you would need to do something to change the fractional flow characteristics.

Of course, none of their reservoirs are really well behaved in that way. With Ghawar, it is so big that it really didn't matter for awhile. Now, however, the real risk is stranding some of the oil due to uneven waterflooding. The developmental strategy is altered to mitigate that risk, employing new technologies along the way. If all goes well, they might get the original URR out after all. So, if you increase the reserves due to the technology, do you decrease the reserves before that due to the problems encountered necessitating the new technology?

Were any of their reserves (such as Haradh or Khurais) decreased after finding problems there, such as the fractures and Super-K in Haradh?

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JoulesBurn on January 3, 2008 - 6:22pm Permalink | Subthread | Parent | Comments top

For example, this is from one of Saleri's presentations:

Abqaiq has produced more oil than were assumed to be reserves in 1950, so what was not known or assumed in 1950? What new insight did they have in the late 1970s and 1980s to justify the increase?

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memmel on January 4, 2008 - 3:27am Permalink | Subthread | Parent | Comments top

This is a good counter point to the technology effect and shows how it could be a large factor in the opposite direction. My best guess is what really happened with Abqaiq is addittional oil was found trapped in another level.

But Simmons has a great paper on this issue.

http://www.simmonsco-intl.com/files/Reserve%20Reporting.pdf

And another good one.

http://www.oilandenergytrends.com/ger/ger_saudi.asp

Note that if you read this second paper Oil And Gas Journal gives a reserve estimate of 64.8 for
Ghawar in the 1970's and it had been in production for some time at that point. This is inline with my estimate of 66 GB.
And of course Abqaiq at 7.5 GB note we have reason to believe the 1970's numbers are better than the 1950's these are very large fields and it takes time to delineate the field using traditional wells.

So does Abqaiq "Destroy" the concept ?

This paper

http://countrystudies.us/saudi-arabia/41.htm

Of the four fields discovered before Al Ghawar--Ad Dammam, Abu Hadriyah, Abqaiq (also seen as Buqayq), and Al Qatif--only Abqaiq and Al Qatif were still producing in 1990. Abqaiq had forty-seven flowing wells. The major producing fields discovered after Al Ghawar, mainly in the 1960s and early 1970s, are offshore and include Manifah, Abu Safah, Al Barri, Az Zuluf, Al Marjan, and Al Khafji in the Divided Zone. Saudi Arabia had a total of 789 flowing wells during 1990, up from 555 producing wells in 1983.

Indicates to me that Abqaiq was in decline in the 1990's.

Its production profile with a URR of around 7-8 GB matches well with that of Phrudhoe Bay at 10-13GB. It's peak production was less. Also this is a old field and was under American production for a long time.

Now I've been unable to find any recent production data for Abqaiq. KSA does not seem to publish consistent per field production numbers if they do then I've not been able to find them.

To be blunt I don't believe this graph and cannot find any easy way to prove Abiqaiq could be this high given it was under American production control for most of its life history.

And whats know of its historical production fits with its estimated URR not with the one claimed in the graph when compared to similar sized fields.

Also note this paper was produced in response to Simmons work.

Another link about the paper.

http://saudioilproduction.blogspot.com/2007/04/fredrik-robelius-on-saudi...

I've read the Saleri paper in the past but cannot find a link to it now.
Overall its very optomistic.

Here is a link

http://www.csis.org/media/csis/events/040224_baqiandsaleri.pdf

And the Simmons paper at the same time.

http://www.csis.org/media/csis/events/040224_simmons.pdf

http://www.csis.org/component/option,com_csis_events/task,view/id,429/

Note the entire paper has been extensively discussed. And its not in agreement even with the results of the current posting.

I'll come out and simply say it.

The graph is pure bullshit.

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jimb on January 4, 2008 - 10:49am Permalink | Subthread | Parent | Comments top

I am a new poster on this site and I am definitely no expert on Ghawar, but the 64.8 billion barrel recovery estimate from the 1970's does not seem realistic at this point in time. Maybe I am confused here, but in figure 9 of Khebab's original post it looks like the average estimate for cumulative recovery to date is roughly 60 billion barrels and based on figure 8 Ghawar's current production is still roughly 5 million BOPD (or 1.8 GB per year), so unless the field entirely stops producing in the next few years it is easily going to pass the 64.8 GB ultimate reserve level. This does not mean it will not go into steep decline in the near future, but there will certainly be a very long production life left for this field although at a much lower rate.

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JoulesBurn on January 4, 2008 - 10:53am Permalink | Subthread | Parent | Comments top

My best guess is what really happened with Abqaiq is additional oil was found trapped in another level.

The Abqaiq reserves plot above is just for Arab-D, so that wouldn't be the case.

From this plot, Abqaiq has produced some from other reservoirs and is predicted to provide a production bump in the future:

Both this and the previous plots came from Saleri's CERA Week presentation:

http://www.cera.com/aspx/cda/filedisplay/filedisplay.ashx?PK=29004

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Sam Foucher on January 4, 2008 - 11:31am Permalink | Subthread | Parent | Comments top

This chart is typical of reserve growth (i.e. better technology + better field knowledge/management), reserves have more than doubled since the 50s but have reached an asymptote since the 90s. If we believe the USGS model, Abqaiq reserves will grow forever simply because their empirical growth model has no asymptote. It shows also that reserve growth after 50 years is problematic unless the field has been mothballed or mismanaged for an extensive period of time.

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JoulesBurn on January 4, 2008 - 11:47am Permalink | Subthread | Parent | Comments top

But what goes into the original estimate?

By circling the thing with water injectors, they've effectively delineated the productive volume. Perhaps they obtained a better understanding of the contours of the Arab-D, but it's hard to believe they were that far off originally that would warrant a change. Perhaps they overestimated the residual oil and realized after watering out a few wells that more was extracted than predicted.

Most of the reserves increase predated extraction technology that would have made a difference, so it would seem to more likely to be reservoir geology issues as opposed to technology.

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memmel on January 4, 2008 - 5:16pm Permalink | Subthread | Parent | Comments top

I can't figure out anyway to justify the numbers from this paper. Given the age of the field.
I can't find a history of production problems that could have been overcome later for example.
Abiaq seems to have a lot of above ground handling equipment not related to the field but piped in from elsewhere.

If you read the quotes I found about the field in the 1990's during the first Gulf War the indication was it still had producing wells but that that the production was not amazing.

Bingo :)

And the oil drum strikes again

http://www.theoildrum.com/story/2006/8/16/13213/1413

http://www.theoildrum.com/classic/2005/06/picture-of-depletion.html

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memmel on January 4, 2008 - 5:45pm Permalink | Subthread | Parent | Comments top

Assuming I found the field in google maps. It looks like a lot of infrastructure is around but dunes seem to be covering a lot of the roads. I could be wrong.

Here is a map with the field

http://www.gregcroft.com/area1indexmap.ivnu

I think I'm in the right place here.

http://maps.google.com/maps?f=q&hl=en&geocode=&time=&date=&ttype=&q=Ghaw...

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JoulesBurn on January 4, 2008 - 6:47pm Permalink | Subthread | Parent | Comments top

Probably. I posted an image with the field outline for Euan awhile back. Have a look:

http://europe.theoildrum.com/node/3100/252277

I am working on a post with a lot more satellite porn.

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memmel on January 4, 2008 - 8:32pm Permalink | Subthread | Parent | Comments top

Looks similar can you post your google link for that image ?

I just noticed most of the roads where covered by dunes.

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43 comments on Saudi Arabia: An Attempt to Link Oil Discoveries, Proven Reserves and Production Data

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