Well static water level

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by jdpete, May 12, 2018.

  1. jdpete

    jdpete New Member

    Joined:
    May 12, 2018
    Location:
    North Dakota
    Recently had a 143' well drilled. It's not producing much at all but has a higher than normal static level for our area (20'). Screened from 60'-140'. There was a very small layer between 45'-55' possibly producing some water but wasn't screened. Could that layer somehow be causing the high static level if it has water and how? Most likely will be drilling a new hole soon. The driller is considering trying to pull some casing and screening that small layer.
     
  2. Boycedrilling

    Boycedrilling In the Trades

    Joined:
    Sep 30, 2013
    Location:
    Royal City, WA
    One of the things that a driller has to watch for is multiple water bearing zones that have different static water levels. This can lead to upflow or downflow between different water bearing zones. I have seen both upflow and downflow in the same well, in excess of 200 gpm. I have also seen downflow from one aquifer to another in excess of 1,000 gpm.

    In your case, if that 45-55 ft zone was producing water with a high swl that the lower zone, you would have down flow without a higher swl.

    I’m currently drilling a test well for a customer. He’s hoping for 3,000 gpm. I’m expecting 1,000 to 2,000 gpm. First water zone I hit was at 117 ft, about 50 gpm. That’s useless for me. I didn’t even stop to get a swl on it. Next water bearing zone was in the 450 ft area. Watered my 10” hammer out at 495 ft. Probably 300-500 gpm. Tripped out to change to a roller bit. Videoed the hole. The 117 ft water was cascading in the well to a swl of 165 ft. The well was caved it with palaganite at 167 ft, with the 50 gpm flowing thru the chunks. Tripped in a 9 7/8” Tricone bit. Advanced the hole to 596 ft. Clay and palaganite was getting to unstable to continue. Tripped out. Videoed the hole. 117 ft zone still cascading. Swl is now 267 ft. Downflow to caved material at 550 ft, downflow goes thru the cave in. Ran a string of 8” casing to bottom. Cased off all water. Tripped in a 8” hammer. Hit a little water again at 635 ft. More water at 746 ft. Hammer was watered out at 749 ft. Tripped out. Videoed hole. Swl is still 267 ft. No leakage at bottom of casing no up or down flow from bottom of casing to td at 749. Tripped in 7 7/8” tricone now at 765. No change in water flow or air pressure. Will probably drill a couple hundred more feet. Might run a test pump in and get an idea of drawdown at 400-600 gpm. Why that gpm? That’s as big a pump as I can get in 8” casing. Then we will pull at the temporary casing out, and ream the hole to production size. 16” or 20” diameter. We know we have to case off the cascading water at 117 ft. We have unstable formations from 165 to 350 ft. That has to be cased off. The big question is will we have to case off the 450 ft water bearing zone? If we can get 1500 gpm with less than 200 ft of drawdown, we can use the 450 ft zone. If we’re going to have more drawdown than that, the 450 ft zone will start as axing and it will have to be cased out also. I could have to end up running 16” casing to as deep as 600 ft. Then I can start on well #2, cause it’s going to take 600 hp to pump 1500 gpm from 600 ft. 700 hp is about as big as you can go on a deep set turbine. Some short set river pump turbines will run 6 pole motors (1200 rpm). They will be as much as 1,200 hp.
     
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  4. LLigetfa

    LLigetfa DIYer, not in the trades

    Joined:
    Feb 6, 2011
    Occupation:
    Retired
    Location:
    NW Ontario, Canada
    How much is not much? How much do you need?
    The driller should know the probability of the 45-55 foot region being viable. I don't know how well the annular space between the casing and the bore hole is sealed, as it is just 5 feet away from the screen. If it is well sealed then it should not affect the SWL. If there is very slow leakage from that region, then the lower region would soak it up as Boycedrilling mentioned.
     
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