<DrumBeat: March 26, 2007 The Oil Drum DrumBeat: March 27, 2007>

330 comments on Water in the Gas Tank

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Darwinian on March 26, 2007 - 8:31pm Permalink | Subthread | Parent | Comments top

Saildog, you ask a great question and I am not sure of the answer. But I do have a couple of comments. "Resting the fields" is a term I have only heard on this, and other, forums. I have never encountered the term in any technical literature or on any book about peak oil or oil production in general.

The only thing I think resting a field might do would be if coning had occurred then shutting the field down for several years might mitigate the situation somewhat. That is oil from the sides of the cone might migrate in and push the cone down some but I am not at all sure about this. Just guessing I would tend to doubt that resting a field would help the coning very much.

But I would bet that it would not help the water/oil mix one bit. I think it would take decades, or even centuries or more for the oil and water to separate inside the reservoir.

However I would just love to hear from someone who does know what the hell they are talking about on this subject because I sure as hell do not. But never having encountered the principle anywhere except on fourms such as this, I tend to doubt that it is a widespread practice.

Ron Patterson

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elwoodelmore on March 26, 2007 - 10:06pm Permalink | Subthread | Parent | Comments top

ron, i agree with you to an extent. my first reaction when i read about "resting" the wells here for the first time was relative to water coning. my experience is that if/when coning occurs, shutting in the well for a time will give an instantaneous improvement but for a very limited time.
however, the saudi's may be "resting" the wells to their benifit. 1) resting the wells has the same effect as production at a lower rate. 2) the combination of high porosity and permeability, reservoir stratification and steep dip may actually result in gravity segregation of the oil and water (some on here dismiss this idea out of hand). 3) during the shut in periods, water may "imbibe" into the lower porosity rock and displace some oil "into the fairway". imbibition is very effective in displacing oil, although limited to a few % of pore volume.

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Stuart Staniford on March 26, 2007 - 10:24pm Permalink | Subthread | Parent | Comments top

At least in Uthmaniyah, the Saudis explicitly have a bunch of wells on cyclic production, where they produce for 6 mos and then rest 6 mos.

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Aniya on March 28, 2007 - 12:25am Permalink | Subthread | Parent | Comments top

Thanks, Stuart,

re: Do they say explicitly why? Or, do you know (for sure) why?

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Stuart Staniford on March 28, 2007 - 1:46am Permalink | Subthread | Parent | Comments top

SPE 98847 saith:

Most of water production comes from high water cut wells located in the flank areas due to proximity to the injection system. A developed production practice was devised to produce high water production wells on cyclic mode. This practice minimized water production and lowered operating costs in mature areas of the field. The cyclic production mode calls for shutting-in wells for six months followed by production for the same period and repeating the same process onward. Implementation of cyclic production was started initially at the end of year 2000 with thirteen high water cut wells. In August 2004, additional twenty-seven high water cut wells were put on cyclic production.

In a cyclic production mode, the mechanism of fluid movements is different than a normal production mode. During the shut-in period, excessive water (heavier fluid) is segregated and pushed down in the reservoir which allows oil (ligher fluid) to be accumulated in the top. Hence, oil will arrive quickly to the well bore column and the well can produce it early at a reasonable rate during the production period.

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PrisonerX on March 28, 2007 - 1:24pm Permalink | Subthread | Parent | Comments top

Stuart, et all,

I thought you might be interested in this story. Though its use for oil fields may not work one day, it is interesting and its about "flow" of liquids and what forces can be used to act upon that flow

http://www.livescience.com/technology/070327_laser_jet.html

"Light is actually pushing onto us slightly. This effect is called radiation pressure," Zhang said.

This gentle pressure generated by photons—particles of light—ordinarily goes unnoticed. But the liquid used in the new experiment—a soapy mixture—has such an incredibly weak surface that even light can deform it. It created a phase change that's a bit like how shampoo turns to soap when you add water, the scientists explained.

The newfound technique might offer a new way to control the flow of fluids through channels thinner than a human hair for biomedical and biotechnological applications, the researchers said.

Quid Clarius Astris
Ubi Bene ibi patria

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ET on March 27, 2007 - 12:46am Permalink | Subthread | Parent | Comments top

In US wells using pumps, resting a well might simply refer to allowing the oil to seep in and fill the borehole. I know a lot of stripper wells operate on a few days a week (or month) type of schedule. Like you, Ron, I don't how the 'resting' would affect a high-production water drive oil field like in KSA, which is obviously going to be quite different than pump driven stripper wells.

The same issue has come up with regard to the Russian wells that had several years of 'resting' before being put into high production again. I suspect it is a combination of geological factors such as oil migration (imbibing) and technological factors such as horizontal wells, etc. that brought about the second Russian peak.

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330 comments on Water in the Gas Tank

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