Sand in well water

[Dewitt]

We had a well drilled 3 months ago and all worked well for 2 months then sand started appearing in the water.

The well is shallow. 45 feet deep with the last 32 feet going into fine sand. It has good flow of 15gpm with very little drawdown.

They installed a 15 ft stainless steel wire wrapped screen 10 1/1000. The pump sits 3 feet above the screen and the staic water level is 10.

Talked to the driller and they are going to come back and redevelop the well with air lifting. I assume that will remove all the fine sand from the well.

My question is...is the 10 1/1000 well screen the proper screen for very fine sand? If the well is redeveloped and just fills with sand over time then it's a bandaid solution.

Anyone have any thoughts/confirmations/solutions. I'm not a well expert so my assumption about the incorrect screen may be incorrect

 

[VAWellDriller]

We had a well drilled 3 months ago and all worked well for 2 months then sand started appearing in the water.

The well is shallow. 45 feet deep with the last 32 feet going into fine sand. It has good flow of 15gpm with very little drawdown.

They installed a 15 ft stainless steel wire wrapped screen 10 1/1000. The pump sits 3 feet above the screen and the staic water level is 10.

Talked to the driller and they are going to come back and redevelop the well with air lifting. I assume that will remove all the fine sand from the well.

My question is...is the 10 1/1000 well screen the proper screen for very fine sand? If the well is redeveloped and just fills with sand over time then it's a bandaid solution.

Anyone have any thoughts/confirmations/solutions. I'm not a well expert so my assumption about the incorrect screen may be incorrect

10 slot screen is very fine and should be able to do its job once the well is fully developed. Sometimes that is hard it they make a lot of water. There is really no other solution than to redevelop, and airlifting is a good method. A swab or surge block may be helpful, but I'm sure airlifting will be a great benefit. With it being so shallow and a good producer that process should be very quick and easy and may even be a DIY project if it needs doing periodically. SS wire wrapped screen is the best there is.

 

[Sponsor]

 

[Reach4]

Let's hope that the sand outside of the screen is a mixture in size, and that only half of the sand is making it through. The bigger grains would stay outside and add to the filtering, so that after a while the smaller grains get blocked too. Let's hope. I am not a pro.

To lift sand/sediment out with air, there are two ways that I know of. One involves a very high rate of air flow with a big engine-driven compressor. The sediment and water fly up and erupt like a geyser. The other way is with an air lift pump. That is much slower, but does not need as much CFM from the compressor. It also requires the water level to be above half way to where the sediment is getting pumped.

When sand gets cleaned out, try to collect a sample for potential later grain size measurement.

https://www.thedriller.com/articles/85569-determining-sand-pack-size

 

[TJanak]

We have a fine sand issue in this area and it seems like the older wells put in with anything over 10 thousandths screen will make sand. I have a couple that do. When I had a new well drilled I ended up using the guy that gravel packed his wells (the second go-around anyways). From what I understand this should help. Not something you can do now, but for future knowledge.

 

[Dewitt]

10 slot screen is very fine and should be able to do its job once the well is fully developed. Sometimes that is hard it they make a lot of water. There is really no other solution than to redevelop, and airlifting is a good method. A swab or surge block may be helpful, but I'm sure airlifting will be a great benefit. With it being so shallow and a good producer that process should be very quick and easy and may even be a DIY project if it needs doing periodically. SS wire wrapped screen is the best there is.

10 slot screen is very fine and should be able to do its job once the well is fully developed. Sometimes that is hard it they make a lot of water. There is really no other solution than to redevelop, and airlifting is a good method. A swab or surge block may be helpful, but I'm sure airlifting will be a great benefit. With it being so shallow and a good producer that process should be very quick and easy and may even be a DIY project if it needs doing periodically. SS wire wrapped screen is the best there is.

Thanks for your assessment. When the well is redeveloped, are they simply flushing the sand our that is inside the screen? Also, if I wanted to do this myself, what equipment would I require. how large of compressor? Ive watched the process on a few youtube vids but not sure of the details on the equipment.

 

[Dewitt]

10 slot screen is very fine and should be able to do its job once the well is fully developed. Sometimes that is hard it they make a lot of water. There is really no other solution than to redevelop, and airlifting is a good method. A swab or surge block may be helpful, but I'm sure airlifting will be a great benefit. With it being so shallow and a good producer that process should be very quick and easy and may even be a DIY project if it needs doing periodically. SS wire wrapped screen is the best there is.

We had a well drilled 3 months ago and all worked well for 2 months then sand started appearing in the water.

The well is shallow. 45 feet deep with the last 32 feet going into fine sand. It has good flow of 15gpm with very little drawdown.

They installed a 15 ft stainless steel wire wrapped screen 10 1/1000. The pump sits 3 feet above the screen and the staic water level is 10.

Talked to the driller and they are going to come back and redevelop the well with air lifting. I assume that will remove all the fine sand from the well.

My question is...is the 10 1/1000 well screen the proper screen for very fine sand? If the well is redeveloped and just fills with sand over time then it's a bandaid solution.

Anyone have any thoughts/confirmations/solutions. I'm not a well expert so my assumption about the incorrect screen may be incorrect

 

[VAWellDriller]

They are trying to remove the finer portion of sand immediately outside the well screen. Hopefully the finer particles will flow through and be removed, and the coarser will pack around the screen and develop a filter pack around the screen. "gravel packed wells"....drillers install a pre-sorted filter gravel in the annular space around the screen....that's all I will install. In a naturally developed well, ( the driller drills a slimmer hole and allows the natural formation to collapse around the screen, the chosen slot size is much more important and the driller needs to develop the well a little longer to remove the fine particles. You wouldn't need much of a compressor; usually the smallest you can rent is a 185cfm towable....and that's more than enough for your well given the depth and yield. I know one driller in a high yield and high static area that uses a small 1/2" line hooked to air tank from his rig air brakes and gets by just fine....probably not more than 10 or 15 cfm.