Water Well - sand problem

I am excavating in back yard a new water well. I will be using the water for watering yard only (not drinking water). I excavated 20 feet below level and the water level is at 11 feet( so there is 9 feet of water). I installed a 4" pipe perforated at the bottom. The problem that I have is that there is a lot of sand that keeps coming in to the pipe. I have tried pumping the sand with a gas water pump but two things are happening: 1) No matter how much sand I take out, sand keeps filtering non-stop to no end and 2) at times I am unable to pump out any sand at all and the pump keeps getting clogged. I am at the point of giving up with this hole. Any advise is welcome.

Thank you.

Well drillers make a filter out of the casing. The perforation in the 4" pipe should be very small, like 20 to 35 thousandths of an inch. Then you gravel pack about 2" thick around the perforations with very small gravel, that almost looks like sand. This makes a filter out of the well casing and keeps sand from getting into the well.

The size of the slots should be only 0.08 to 0.10 With a screen this size there is no need to waste time and money with gravel.
20 to 30 is way too big.

If you are trying to pump the sand out with slots that big, there is no way thats going to happen. The sand is not going to stop with a screen that size.

For a well drilled in sand like yours, the sand has to be walled off with a heavy mud.
If its not held back with say drilling mud of some kind, the sand is not going to stop.

Travis

Every area is a little different. Here we use .035 slots and 00J gravel or silica sand. We don’t count on the mud wall holding back sand. We actually do everything we can to break up the mud wall so we get more water from the well. You can buy a filter pac screen. Slot thickness needs to be sized to the sand, and the gravel pac sized to the slot size.

The only wells drilled in sand that NEED to be gravel packed, are only wells set in silt type sand.
All other wells drilled in sand do not need to be packed. They just need the right size screen.

When a well is properly developed, there is no mud in it. The only mud that gets in to the sand is from the drilling process itself.

Yes all mud needs to be broken down and taken out of the well sand, other wise it call a post hole.

Our wells are in sand that looks like it belongs on the beach. Without small perf and a good gravel pac, you would be pumping this sand forever.

Thanks for all the advise. I ended up buying a new pipe and drilled smaller holes and placed a filter fabric around the pipe like a sock. I took out all the mud from inside the pipe. It seems to be working. A bit of sand still filters through but not much. I will give it a few days and see what happens.