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Well drilling woes

Well drilling woes

(OP)
I have a well driller who drilled a well for me that went down 270 meters and "didn't find any water".  However, as I listened above the hole, it sounded like running water.  So, I lowered a HD camera into the hole.  As can be seen on the video http://www.youtube.com/watch?v=6K6BQ6cZwE8 there is at least some water in the well although I will agree that it is hard to tell how much.  All I need is about 30 liters (8 gallons) per minute and it looks to me like I've got that.

The big issue, however, is that the water is not rising up and spilling out of the hole (this is a problem according to the driller).  It seems to me that if your hole cuts through a crack in the rocks that has water running through it, that there will almost always remain an outlet for the water in addition to the inlet.  So, it doesn't surprise me that the water is not filling up and flowing out of the hole.  

The driller is telling me that I should drill a second hole next to the existing hole, "a couple of meters away".  As I pay for each meter drilled, I want to make sure this is necessary and advisable.  

Three definite questions:

1. Can anyone with experience tell me how much water is flowing from the video (http://www.youtube.com/watch?v=6K6BQ6cZwE8)?  Obviously, I'm not expecting a solid number, but if someone has enough experience to say it is definitely no more than x, it would help me a lot.

2. Is a hole usable if you've drilled down 270 meters but have water at 100 meters?  If so, where do you put the pump and how far down would you case the well?

3. If the water is running out at the same rate it is running in (I know this because the water level has been the same for weeks now), how does one trap the water?  It would seem to me that putting the pump anywhere below the level of the outlet "crack" would do the trick, but with 170 meters of water filled in the lower portion of the hole, how on earth do I know where that crack is?  It would have to be below the surface to have any pressure on it to force it back into the rocks.

I realize this is a huge bunch of questions, but any advice on any of the issues would be greatly appreciated.

Thanks.
 

RE: Well drilling woes

Have you conducted a pump test?

RE: Well drilling woes

(OP)
Obvious first question.  No!  The driller left the site as "dry" and didn't do a pump test because he didn't think there was water.

 

RE: Well drilling woes

Call him back to test the hole.  Maybe the drilling mud clogged the fractures.

RE: Well drilling woes

(OP)
Agreed, that is what I need to do.  Is there any saving the hole if it is 270 meters deep but the water is coming in at 100 meters?  

Thanks for your time.

RE: Well drilling woes

I would recommend joining a website forum called contractor talk and posting a similar question there.  I have seen some knowledgable well drilling discussion amongst the contractors there.  I asked the mods before I joined if they had an issue with a civil engineer joining and they did not.

RE: Well drilling woes

if you have a competent driller, no problem. they can case / screen the well at any depth. Did they log the hole? Ask them for the logs. then give the logs to a new driller. make sure you ask the new guy to pull his head out first...

RE: Well drilling woes

(OP)
Thanks Sam74.  I posted on Contractor Talk as well.

RE: Well drilling woes

Our well was similar depth, and produced less then 1GPM when first tested, and 60GPM after hydrofracture, which was part of the drilling quote.  A pump test is essential to determine the actual yield.  A true artesian well (overflowing) is not common, at least in our area, and can actually be a problem, since you'll have to deal with the overflow.

Peter Smart
HydroCAD Software
www.hydrocad.net
 

RE: Well drilling woes

(OP)
Hey Sam74, wow that hurt.  They literally "banned" me from their site.  I guess I wrote something horrible or I'm so far from a contractor they can't even say sorry.  Ouch.

RE: Well drilling woes

They can be a little harsh especially to newbies.  I think they have a strict requirement about making a first post and introducing yourself before asking questions or offering advice.

RE: Well drilling woes

Perhaps you will is not deep enough.

I am aware of some wells drilled in rock in the northeast where the well acts as a reservior. The average production is not adequate for peak use, but the water will accumulate over time.

Your well contractor should have enough experience drilling wells in the local that you are in. Perhaps you should consult another local well driller.

RE: Well drilling woes

If this is for a house, 8 gpm is a big number.  If you feel there's a need for a peak demand of 8 gpm, then you may have what you need for the duration of the demand in well storage (or get a holding tank).  After the duration of the demand, the well can recharge at 1 gpm or whatever the yield happens to be.

You truely should have a pumping test performed.  I mean if you pump at 4 gpm for a few hours and the well level keeps heading down, then you throttle back to 2 gpm to see if you can demonstrate a sustained yield.  Somewhere there is a sustained yield that may support the average well demand.

Your well driller may be correct - maybe you don't quite have the yield.  That said, moving over a few feet doesn't seem to make sense to me.  It's not like you could run both at once and hope for each to perform without influence to the other. . .

f-d

¡papá gordo ain't no madre flaca!

RE: Well drilling woes

(OP)
Thanks bimr & fattdad,

I would suspect that this well will never be adequate for peak use. The 8 gallons per minute is for constant draw and a storage reservoir for peak use.  I have to service 20 homes and 8 gallons per minute continuously will suffice.

We are going to do a pump test now, but the problem is that the well driller needs to ream out the pilot hole he dug to do a pump test and we are not sure if the flow is enough to be worth the extra work.  But, we've made the decision to go ahead so I'll report back with the pump test results.

Thanks for all the feedback.
 

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