<DrumBeat: April 7, 2007 The Oil Drum DrumBeat: April 8, 2007>

217 comments on The Status of North Ghawar

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totoneila on April 7, 2007 - 6:51pm Permalink | Subthread | Parent | Comments top

Hello TODers,

Great work by all!

I refer everyone to Garyp's great find:

http://www.blackwell-synergy.com/doi/pdf/10.1111/j.1365-2478.2004.00473.x

"Houston we have a major problem with Uthmaniyah"

I think we need more information on the moving mud wave in the pressurized waterfront [in all areas of Ghawar] as it pertains to horizontal/vertical permeability/porosity ratios--could the mud wave be making the waterfront behave more like a breaking wave than a rising tide through the payzones?

General carbonate reservoirs have greater permeability and porosity as you go from payzone bottom to top. The mudwave is clogging the bottom making it easier for ever increased waterfront vertical permeability through ever more porous payzone toprock. Increased injection pressure maybe making it very hard to keep the mud moving causing a waterfront 'breaking wave action in the reservoir sweep.

Sorry, wish I had more time, but busy today. Please flog this mud wave implication as best as you can--Good luck!

Bob Shaw in Phx,Az Are Humans Smarter than Yeast?

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Euan Mearns on April 7, 2007 - 7:59pm Permalink | Subthread | Parent | Comments top

Bob - I've not forgotten about your question on a tilted contact - but it is a complicated question to answer - which evidently has been discussed by the SPE for 30 odd years - so I'm not sure that I can contribute a huge amount in a short post.

Suffice to say this:

1. Any aquifer (water) pressure gradient across the field related to a tilted contact is unlikely to be significant to the present debate on reservoir depletion. Variations in pressure caused by production and injected water are likely to be over riding.

2. The geological processes responsible for the tilted contact will be very important in understanding the "hydrodynamics of the reservoir" and how it responds to production.

I know this won't help much but the key issues right now are the size of undrained reserves in good quality reservoir in Northern Ghawar.

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totoneila on April 8, 2007 - 5:26pm Permalink | Subthread | Parent | Comments top

Hello TODers,

http://www.spe.org/elibinfo/eLibrary_Papers/spe/2006/06EURO/SPE-98847-MS...
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ABSTRACT/details behind paywall =(

Water Production Management Strategy in North Uthmaniyah Area, Saudi Arabia

A water management strategy was initiated in the North Uthmaniyah area of Ghawar field in late 1999. The strategy main objectives are to reduce operating expenses associated with water handling and avoid capital investment required for the expansion of water handling facilities while engendering a more efficient recovery process. The strategy was implemented through four initiatives: operating of high water cut wells on a cyclic basis, conducting rigless water shut-off jobs, drilling horizontal sidetracks of existing vertical completions and drilling wells with partial penetration completions. [There is much more detail in the abstract, please read]
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http://home.entouch.net/dmd/ghawar.htm

Specifically, I refer you to the second graphic of Alexander: http://home.entouch.net/dmd/ghawarwaterfront.JPG

Does the oilwell placement make sense? I expected a more even spacing, or else well concentration along the top of the incline [the eastside injection well pattern just above the bottom tarmat makes sense]. Also, can someone access the graphics and charts in this article [I can't]:

http://www.oilandgasnewsworldwide.com/bkArticlesF.asp?IssueID=115&Sectio...
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[Selected excerpts]

Robert Phelps, Richard Black, Harold Triebwasser, Ali Al Shahri and Fahad Al Ajmi of Saudi Aramco discuss ways to integrate data to identify high-stratiform permeability regions in the 'Uthmaniyah area of Saudi Arabia.

A PROJECT was undertaken at Saudi Aramco to develop a quantitative definition of super-K; map this quantitative definition of super-K and compare to other geological and reservoir properties; determine a possible correlation between the data in order to determine what parameters may be influencing super-K events; and use 3D visualisation to review the data to determine if there are trends or similarities in the data.

Using all open-hole flowmeters in the 'Uthmaniyah area, a Fluid Flow Index (FFI) was calculated.

To better understand the quantity of data used in this study it is important to note that there were 1,366 'Uthmaniyah wells analysed.

This represents about $82 million-worth of open-hole logging cost. A total of 799 wells had flowmeters run at a total cost of $16 million, of which 462 wells were open-hole flowmeters.

The majority of these wells had several and some as many as 16 open-hole flowmeters. Since a data point is taken at every 0.3 m interval, measuring both water and oil, this translates into approximately 2.5 million data points that were used in this study.
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But, I want F-F,SS, and Euan, plus interested others to see this MOTHERLODE OF GHAWAR INFO [WARNING 540 page PDF]:

http://pangea.stanford.edu/~jcaers/theses/thesisJoeVoelker.pdf
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page 54 -- placement of all wells in Ghawar
page 106-120 --UTHM waterflood detail and super k

The rest of the PDF is extreme detail that I haven't had time to study.

Other links here:

http://pangea.stanford.edu/~jcaers/publications.html

Bob Shaw in Phx,Az Are Humans Smarter than Yeast?

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garyp on April 8, 2007 - 6:23pm Permalink | Subthread | Parent | Comments top

Well that puts paid to me doing any real work tomorrow.

Can I point to two papers that result from the trawl to find the original paper for the oil and gas ref.

Integration of Data to Identify High-Stratiform Permeability Regions is the original paper, complete with pretty pics.
&
Simulation of Super-k Behavior in Ghawar by a Multi-Million-Cell Parallel Simulator

There are many more illuminating papers via here. These are Aramco's own papers and there are lots of bits of data to ingest.

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Edit: And Fractional Flow REALLY needs to comment on this paper:
Equations for Water/Oil Relative Permeability in Saudi Arabian Sandstone Reservoirs

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totoneila on April 8, 2007 - 6:27pm Permalink | Subthread | Parent | Comments top

Hello TODers,

When you use the PDF magnifying tool to zoom in on the oil wells on page 54 of the Motherlode link--alot more detail becomes visible.

Does it show OWC at the various stratigraphic levels inside the well, gas condensate output for some, Horizontals & MRC?

What details do the shapes, and colors mean for each extraction well? for each injection well? Is there any way to figure this out?

Bob Shaw in Phx,Az Are Humans Smarter than Yeast?

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garyp on April 8, 2007 - 7:27pm Permalink | Subthread | Parent | Comments top

Bob, and anyone else looking at the data, I heartly suggest going through the Aramco Journal of Technology. There is much there that informs and provides evidence that can be pieced together.

The page 54 oil well pic doesn't tell me much, the resolution is too low. However there is enough in the JoT articles to give a fairly complete picture I think.

As an example Simulation of Vertical Fractures and Stratiform Permeability of the Ghawar Field provides a figure that answers precisely the question of where the Uthmaniyah map and cross section output we have goes.

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totoneila on April 8, 2007 - 9:39pm Permalink | Subthread | Parent | Comments top

Hello Garyp,

Great Job! This area is/has been studied extensively by Aramco because:

From the Motherlode link:
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Moore[55] reported superficial flood front velocities
v = 15 ft=day over an 8 km span
on the Uthmaniyah flood front.

Saudi Aramco (SA), is attempting to resolve observed, massive, unmitigated hydraulic conductivity between injection and production wells separated often by more than 1 km.

The first fundamental fnding: the predominate, repeated waterflood pattern is that of line drive, specifcally under long and thin, rectangular pattern boundaries. Second: Ghawar water injection wells are often inadvertently hydraulically fractured with unpropped fractures [basically, shooting themselves in their own feet!].

We conclude that these conditions exacerbate the problematic super-k condition, that of early water breakthrough. Our hypothesis for the structure of super-k, containing essential discrete fracture network components, naturally leads to a supposition that the two conditions stated above, are conducive to the formation of highly
conductive pathways, consisting of hydraulic fractures at injection wells, connecting to natural discrete fracture systems, culminating in a network that may significantly
affect production well performance, because it resides in a long, thin bounded region, the tight waterflood pattern.
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I haven't read everything yet, but Aramco mentions horizontal wells watering out instantly, water over-riding oil, loss of drilling mud, and other anomalies due to widespread DFNs.

Bob Shaw in Phx,Az Are Humans Smarter than Yeast?

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217 comments on The Status of North Ghawar

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