[The Well] sand in wells

[Scott Fowler]

This is where the experts live, so here is a question. Our firm along with others that serve Whidbey Island in Washington state have notice an increase in wells making sand. The wells have been in service from 5 to 40+ years. All of the wells have telescoping screens with lead or k packers. All of the well have been filmed and no damaged screens or casing exist. The sand that has been bailed out (in most cases) is larger than the screen slot allows. There hasn’t been any serious seismic activity for a while. The ph of the water is a low 6.5 to 7.5. None of these well produced sand until the last two years. Any ideas?

 

Scott Fowler CWD/PI

Dahlman Pump & Drilling Inc.

 

See you all at the EXPO in New Orleans

NGWA is not responsible for the authenticity or accuracy of information contained within this message. Published statements do not necessarily reflect the opinion of NGWA. Products and services that are mentioned or advertised within this site do not carry any kind of endorsement by NGWA.

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[John Jansen]

Scott,

 

We see sand pumping increase in screened wells when a significant portion of the screen plugs and entrance velocities increase on the remaining portion of the screen.  We have videoed wells while pumping and observed thin portions of the well screen blowing sand.  In those cases a good chemical or physical cleaning of the screen and formation adjacent to the screen can stop the sand and improve the yield.  Your observation of the bailed sand being larger than the slot size allows has me baffled.  It could be that the finer material is being pumped out of the well and only the coarser material settles to the bottom.  Are the grains really larger than the slot size or could you have many grains sticking together cemented by mineral scale?

 

Good luck.  See you in New Orleans.

 

John Jansen

ENTRIX

Senior Consultant

1388 Colonial Blvd., Fort Myers, FL 33907
DIRECT: 239.829.7020 • MAIN: 239.574.1919 • CELL: 239.896.0576 • FAX: 239.574.8106

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[Joseph W Sheahan]

Scott –

 

Have you had the sand analyzed?  Were these wells installed with an engineered filter pack or one naturally developed from the formation sand?  Whichever the case, a starting point would be to determine whether the sand found in the screens is of the same composition.  I suspect that there may have been a slight geochemical change in the aquifer which is causing precipitation in the screens and, perhaps, in the formation.  Has there been any noticeable decline in the productivity of the wells?

 

P.S.  Your island is one of the most beautiful places on earth.  Keep me posted.

 

            Joe Sheahan

 

Joseph W. Sheahan

President

Ground Water Solutions, Inc.

6150 Columbia Street

Haslett, MI 48840

(M)   517.648.0859

 

DISCLAIMER/CONFIDENTIALITY: This communication, along with any documents, files or attachments, is intended only for the use of the addressee and may contain legally privileged and confidential information. Any document attached is a legal document and should not be changed or altered without the knowledge and approval of legal counsel. The sender takes no responsibility for any alterations, additions, revisions or deletions to any such document. Due to software and printer variations, documents printed at the recipient's location may vary from the original printed document.

 

 

 

 

From: flou...@nwlink.com [mailto:blmailer-thewell...@biglist.com] On Behalf Of Scott Fowler
Sent: Monday, December 07, 2009 1:13 PM
To: the...@ngwa.biglist.com
Subject: [The Well] sand in wells

 

This is where the experts live, so here is a question. Our firm along with others that serve Whidbey Island in Washington state have notice an increase in wells making sand. The wells have been in service from 5 to 40+ years. All of the wells have telescoping screens with lead or k packers. All of the well have been filmed and no damaged screens or casing exist. The sand that has been bailed out (in most cases) is larger than the screen slot allows. There hasn’t been any serious seismic activity for a while. The ph of the water is a low 6.5 to 7.5. None of these well produced sand until the last two years. Any ideas?

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[Edward Butts, PE]

Scott, I have actually seen this phenomena happen before down here in certain parts of the Willamette Valley, especially in several municipal, irrigation, and cannery wells, and it took me some time, trial and field testing, and research to understand what I think was happening. In our case, the wells that started pumping sand were usually drilled and developed during a period when there was little competition for water from neighboring wells. As more wells were drilled and more water extracted from the aquifer, the pumping well, generally already beginning to show its age due to plugging of the screen, began to exhibit greater ranges of drawdown as well as recovery. IN many of these cases, especially the older wells at some of the canneries, development may have originally seemed adequate as sand abated during development, however, as many of the wells now had lower static levels, drew the pumping levels further down, and resulted in changes in recovery periods and levels, the hydraulic characteristics outside of the well screen also changed, often resulting in a redistribution, washing, and turbulence of the filter pack, often to the point where voids would occur, allowing room for the material to move around through constant washing and redistribution for entrance into the well, depending on the cross-sectional shape and size of the grain, enough to draw sand into the well itself, either natural or artificial material. Like you, we observed no appreciable damage to the screens and there were no openings created that would easily allow sand to pass into the well, but we saw it nonetheless, often in a size larger than the slot. Once the process started, it was often very difficult to stop it as voids began to occur adjacent to the screen face. Many times, we were able to abate, or at least, slow it down, through additional development, under-pumping, and/or a series of aggressive redevelopment (depending on the actual conditions in and around the well). There were also some of the obvious cases, especially those with "K" packers, where the packers would slip or deform sufficiently to allow sand into the well, but I am sure you know about those already. I will also admit that there were a few times we could not totally stop the sand, however, with prudent care and the right combination of redevelopment, pump selection, and understanding what was happening, we were able to control the condition in most of the wells. Hope this helps,

Respectfully, Edward Butts,PE,CWRE,BCEE,CPE,CPI,CID,DABET,FASCE
4B Engineering & Consulting, LLC
3000 Market St. NE, Suite 527
Salem, OR 97301
Ph: 503-589-1115--Fax: 503-589-1118
E-Mail Addresses:1)ep...@juno.com-2)ep...@4bengineering.com

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[Steve Lueck]

Greetings,

Did the videologs of the wells include sideview?  If not, then you probably would not be able to see the eroded areas that allow sand passage.  There is some chance that you might have some filter pack that managed to get past the packer as well.  With careful observation, we can usually see where sand is starting to cut screen and supports but it is not always easy, particularly when biological activity is high.

 

 

Steve Lueck
Tucson Water
Water Resources Management/Hydrology
P.O. Box 27210
Tucson, AZ  85726-7210
(520) 837-2233

cell:  (520) 419-5921

>>> "Joseph W Sheahan" <jwsh...@gwsi.biz> 12/7/2009 11:38 AM >>>

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[Scott Fowler]

Thanks for the quick replies. The camera we used does have side view. The screens all where natural sand pack. Most did not have an engineer involved and the static levels have not changed. The majority of the wells did need the screens cleaned. These are all Class A well systems and I’m sure there is more demand on them now then when they were original installed.

Thanks Scott

 

From: Steve...@tucsonaz.gov [mailto:blmailer-thewell...@biglist.com] On Behalf Of Steve Lueck
Sent: Monday, December 07, 2009 10:47 AM
To: the...@ngwa.biglist.com
Cc: Kevin McCray
Subject: Re: [The Well] sand in wells

 

Greetings,

Did the videologs of the wells include sideview?  If not, then you probably would not be able to see the eroded areas that allow sand passage.  There is some chance that you might have some filter pack that managed to get past the packer as well.  With careful observation, we can usually see where sand is starting to cut screen and supports but it is not always easy, particularly when biological activity is high.

 

 

Steve Lueck
Tucson Water
Water Resources Management/Hydrology
P.O. Box 27210
Tucson, AZ  85726-7210
(520) 837-2233

cell:  (520) 419-5921

>>> "Joseph W Sheahan" <jwsh...@gwsi.biz> 12/7/2009 11:38 AM >>>

Scott –

 

Have you had the sand analyzed?  Were these wells installed with an engineered filter pack or one naturally developed from the formation sand?  Whichever the case, a starting point would be to determine whether the sand found in the screens is of the same composition.  I suspect that there may have been a slight geochemical change in the aquifer which is causing precipitation in the screens and, perhaps, in the formation.  Has there been any noticeable decline in the productivity of the wells?

 

P.S.  Your island is one of the most beautiful places on earth.  Keep me posted.

 

            Joe Sheahan

 

Joseph W. Sheahan

President

Ground Water Solutions, Inc.

6150 Columbia Street

Haslett, MI 48840

(M)   517.6480859

 

DISCLAIMER/CONFIDENTIALITY: This communication, along with any documents, files or attachments, is intended only for the use of the addressee and may contain legally privileged and confidential information. Any document attached is a legal document and should not be changed or altered without the knowledge and approval of legal counsel. The sender takes no responsibility for any alterations, additions, revisions or deletions to any such document. Due to software and printer variations, documents printed at the recipient's location may vary from the original printed document.

 

 

 

 

From: flou...@nwlink.com [mailto:blmailer-thewell...@biglist.com] On Behalf Of Scott Fowler
Sent: Monday, December 07, 2009 1:13 PM
To: the...@ngwa.biglist.com
Subject: [The Well] sand in wells

 

This is where the experts live, so here is a question. Our firm along with others that serve Whidbey Island in Washington state have notice an increase in wells making sand. The wells have been in service from 5 to 40+ years. All of the wells have telescoping screens with lead or k packers. All of the well have been filmed and no damaged screens or casing exist. The sand that has been bailed out (in most cases) is larger than the screen slot allows. There hasn’t been any serious seismic activity for a while. The ph of the water is a low 6.5 to 7.5. None of these well produced sand until the last two years. Any ideas?

 

Scott Fowler CWD/PI

Dahlman Pump & Drilling Inc.

 

See you all at the EXPO in New Orleans

NGWA is not responsible for the authenticity or accuracy of information contained within this message. Published statements do not necessarily reflect the opinion of NGWA. Products and services that are mentioned or advertised within this site do not carry any kind of endorsement by NGWA.

 

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[Edward Butts, PE]

Scott, After signing off I realized I did not comment on the water quality potential. With a natural raw water pH of 6.5-7.0, I would not expect the water to be overly aggressive (depending on the alkalinity and other parameters), however, I have seen many shallow (usually < 40')groundwater supplies that test at a reasonable pH above ground once the Carbon Dioxide has released from a saturated state, but the pH is actually far less under saturation conditions in the aquifer, sometimes as low as 5.0. This can only be verified through an immediate sample and test at the wellhead, but I still seriously doubt the water is aggressive enough to the stainless steel screens anyway. Obviously, if the water is low in pH, the likelihood of being severe in the other direction, encrusting, is also low. If you do suspect water quality to be a contributor, I would highly suggest a series of wellhead tests for carbon dioxide, dissolved oxygen, and pH, along with lab tests for iron, calcium hardness, manganese, total dissolved solids, and the Ryznar Stability Index. Galvanic action or electrolysis is also a remote potential, but the chance of those occurring on so many wells to cause the same type of outcome is very remote.

Respectfully, Edward Butts,PE,CWRE,BCEE,CPE,CPI,CID,DABET,FASCE
4B Engineering & Consulting, LLC
3000 Market St. NE, Suite 527
Salem, OR 97301
Ph: 503-589-1115--Fax: 503-589-1118
E-Mail Addresses:1)ep...@juno.com-2)ep...@4bengineering.com

____________________________________________________________
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[Joseph W Sheahan]

Scott –

Do you conduct Specific Capacity tests on these wells as part of a maintenance program?

                       Joe

[Scott Fowler]

On some of them. We were called in when production started lessen. We were able to get the production back on all of them but some stilled made sand.

 

Scott

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[Joseph W Sheahan]

Scott –

I would still like to see a mineralogical analysis of the sand.  Someone in the area must have an X-Ray diffraction unit.  There may be a better way to analyze it but I’m a hydro, not a  mineralogist.

Are you going to New Orleans this week?  Let me know if you want me to pursue this?

 

           Joe Sheahan

[Albright, Randy]

The City of Portland has had K-packers fail in several wells with telescoping screens; we believe this is due to high differential pressures created in the annular space across the K-packer, in our case at well start-up, combined with a well design that did not include a pressure relief screen in the well casing riser below the K-packer in the casing overlap area.  I suppose lead packers could also fail in the same manner, if the differential pressures were high enough.

 

If this has only become a problem in the last two years, perhaps something has changed recently that has increased the differential pressure across the K-packers, such as the installation of larger capacity pumps and/or deeper pumping levels due to higher pumping rates, more well interference or lower well efficiencies?

 

Once the K-packer has failed, it allows both the original filter pack material and formation sand to be produced through the annular space between the surface casing and the well screen riser.  A downhole TV survey may be able to confirm a K-packer failure, unless the K-packer is hidden behind, below or within some sort of reducing assembly installed at the telescoped joint.  Good original construction records could help you determine exactly how the K-packers were originally installed.

 

To repair, you would need to remove any such reducing assembly and, if possible, also remove the failed packers.  Then you would need to sound the filter pack, replace any missing filter pack, and reseal the annular space with something more permanent than the original K-packer, such as a cement grout plug or a metal swage.

 

Of the three wells I have evaluated for this type of K-packer failure and sand production, one was successfully repaired using a cement grout plug to seal the annular space, reducing the sand content of the water produced by the well from 30-70 ppm to trace amounts; the other two wells are still awaiting repair.

 

None of our newer wells which were designed and constructed with pressure relief screens have had this problem.

 

-Randy Albright, R.G.

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From: flou...@nwlink.com [mailto:blmailer-thewell...@biglist.com] On Behalf Of Scott Fowler

Sent: Monday, December 07, 2009 10:13 AM

To: the...@ngwa.biglist.com
Subject: [The Well] sand in wells

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