DIY well drilling / trench digging for GSHP

[Vlad]

Originally Posted by DavesPlanet

I've started a geo drilling rig, I am using 1" schedule 40 steel pipe and a 5HP 220V motor with 30:1 reduction gearing. Plans and construction pics online at
davesplanet.net/davesplanet/make-your-own-DIY-geothermal-drilling-rig
(apparently newbies are not allowed real links, enjoy the copy/paste)
The goal is a 3" hole 150' deep. Nothing to hit here in Iowa except that tough Iowa clay and the occasional rock. No licensed driller needed if the homeowner does the work themselves. I'll be loaning this drill out to family, friends, and church members this summer to take advantage of government incentives. Total cost to install a 4 ton Climatemaster 27 after all rebates (from the energy company) and tax credits is about $2k if you do the work yourself.
Dave

I would use gas or propane converted engine. With electric motor 220V 5 HP you have a good chance to end up 6' down. You will need a ton of protection equipment for this motor. Especially if you have plans to land it.....

Also gas engine is easy to adjust RPM. You will need it more time slow then full speed. Variable drive for 220 5 HP motor is even bigger pile of $$$$.

The best way is hydraulic. Full RPM and torque control and reverse.

I do understand it cost more $$$. Just get a good strong reduction gear and mount vertical gas engine. You can even build reduction gear using sprockets an heavy duty chain.

I noticed many cement mixers have very strong heavy duty reduction gear.

[AC_Hacker]

I have to agree with Vlad, that using electric power is dangerous.

I did use electricity, 120V and I didn't die but I did hear the angles singing a few times. It's no laughing matter. You need to realize that if you used drilling mud, it will actually make the conductivity greater... and when you are drilling, wetness will be almost everywhere.

When I was doing my drilling, I used GFI on my power. Then at one point, the GFIs started popping everytime I started to drill, so I moved my power plug to a non-GFI source. That is when I got the nasty shocks. If you do decide to go electric, figure some way to use GFI. I know it is possible with 220V. It may not be cheap, but neither is a funeral. And if the GFI pops, pay attention to that warning and fix the problem. Please don't be as stupid as I was.

We really do want you to succeed.

Now, if you used your 5HP motor as the prime mover to drive some hydraulics, your drill rig would be electrically insulated from power. Might want to consider that.

Also, I think that homemade swivels are OK. Mine served me well. But the one you have pictured needs much bigger holes in the pipe for the mud to flow through. The force of the mud is a very important part of your tool, give it every chance to work for you. I'd suggest making the holes at least 1/2" in diameter. It won't weaken the pipe as much as you might think.

Your 1" pipe is certainly better than my 3/4" pipe, so depending on soil conditions, you may be OK.

Also, having a two sided bit is not the best. It will tend to flop around in the hole and make a triangular hole. An old driller told me about that one. I didn't believe him until I looked closely, and he was right. A three-sided or 4-sided bit is better.

Also, I see in your photo, that you have your motor and gear reducer mounted to wood. I hope that the wood is just for a mock-up, because when you start drilling, you're going to encounter some serious forces. Mother earth will not give up easily... she'll fight you, but you can win.

So, what do you know about your soil conditions so far?

Best,

-AC_Hacker

[Vlad]

DavesPlanet, I just looked at your plans........

The swivel MUST be bigger, Holes MUST be bigger. You will have no flow especially if you have plans to drill 150'. You need water flow to lift your cuttings up from 150'. It looks like you want to use generator. You will need a monster generator like 15-20 KW to start and run your 5 HP motor.

Also this motor is so called 5HP motor. My air compressor real 5 HP electric motor has 1 1/8" shaft. This looks like 5/8". This reminds me my vacuum cleaner 7.5 HP 110V and it works from regular 15 amp circuit. Marketing department has no even basic knowledge about Oms Law.... Now this idiots started writing PEAK 7.5 HP which is still a joke....

You don't need 90 degree reduction just mount motor vertically.

[DavesPlanet]

Thank you all for the great replies, that's why I came here, to learn from the mistakes of people who came before me.

Please understand my primary drive to build this is to install geothermal for friends and family, I have already trenched in my own geo the hard way. I thought I had the parts laying around to put this together for a few hundred dollars (mostly cost of pipe). If I have to put real money into this to buy hydraulic parts from scratch then the project might be dead.

The holes in the swivel - I will enlarge them to 1/2" as suggested - but the idea was to pump mud into the tub and let the mud and water separate through screens and gravity and to shovel mud out of the tub. I had hopes of pumping very dirty water, not mud. I'm using a 3/4 HP sump pump, not a mud pump. The sump can move a whole lot more water than actually fits through a 1" pipe. I know the up-flow velocity from my 3" hole will be almost 7 times slower than the down flow, which will work for dirt but not pebbles and not sure about clay.

The shaft on the 5HP motor is 0.5" and matched the reduction gearing shaft (which was salvaged from a small tiller). The 90 degree reduction is because that's the direction the salvaged gears turned.

I had done the math on the generator. The motor pulls 12 amps at full power, that's under 3KW, the generator is 5KW.

The reason for using the generator is because it puts out the 220v I need for the motor and I already had the motor and the generator. The 220V motor isn't from a vacuum cleaner, it's from a hot tub, and dealers price and sell these based on their HP, but still I am considering that a 5HP gas motor might have a larger shaft...

I started with a flat bit because the bit I saw in the hydra-jett.com video was a simple flat bit. I can expand the drill bit to a 4 sided tool, that's just a bit more cutting and welding work. I'm not yet visualizing an issue with a flat tool, but I have no problem acknowledging your superior understanding of a challenge I have just started to learn, and I can certainly see a 4 sided bit would be better.

As for the wood frame - I thought since the shaft and pipe are directly supported by the winch the only forces on the frame are going to be torque. I don't want to underestimate the torque, but I wasn't expecting it to destroy a solidly built wood. I will give this some more thought.

The soil in Iowa goes through layers of dirt, sand, and heavy solid clay, with few rocks.

Speed control? My motor is 2 speed, so I might be able to switch from 2 revolutions per second down to 1 revolution per second, but I had considered I would be more interested in the downward speed of the pipe, if I hit a hard spot I would back up and go down much more slowly. Why would I be interested in reducing the rotation of the shaft?

I do appreciate all the great help and advice, thanks for helping make this project a success!

Dave

[AC_Hacker]

Originally Posted by DavesPlanet

Thank you all for the great replies, that's why I came here, to learn from the mistakes of people who came before me.

The way the fluid (and additives) that you use in a rotary drill works needs to be explained, as it's not intuitively obvious. It serves several functions:

• Cooling the bit, so as to not draw the temper
• Lubricating the bit so that it continues to turn
• Souring out the softer, sandier soil bits
• Washing debris from the tip of the drill, so it continues to cut well
• Lifting cuttings to the surface of the drill hole
• Forming a 'skin' inside the hole so that drilling fluid is not lost

The lifting of the cuttings is probably the most complex and requires the most detail. If you drop a pebble of some size into a pool of water, it will sink at some velocity. If you were really interested, you could actually measure it. But just for the purposes of illustration, let's say it is 2 feet/second.

If you have dislodged a pebble from the bottom of your hole, the cutting fluid can wash it out of the hole. If the volume of water you are pumping down the pipe results in a fluid velocity coming back up of 1 foot per second (and the pebble sinks at 2 feet per second) the fluid will not wash the pebble out of the hole, and that pebble and all the other pebbles you dislodge will stay at the bottom of your hole and eventually bind your drill string.

So in the case of our illustration, you will need an upward fluid velocity of at least 2 feet per second or better.

So getting back to your pump, etc. you will need to send water down the hole considerably faster in order to achieve the velocity required to lift debris out of the hole.

So, one of the additions to drilling mud is Bentonite clay. This makes the drilling mud thicker, so that debris will not sink so fast, but it also makes the mud more viscous and more pumping power is required.

There's a superb Wikipedia entry on Drilling Mud HERE.

In my back yard, I originally was using tap water and no pump, it worked great until I got down to 14 feet and the sand granules were large enough that I was losing water faster than I could supply it. If you have fine sand/clay mix, you might be able to get down quite a way with just city water. Also, although I didn't recognize it immediately, the sand was caving in on my hole and grabbing the drill string. Later tries with drilling mud that included Bentonite really helped because they formed a skin on the inside of the hole which kept me from losing water, and also helped hold the sand cave-ins back partly because of the skin, partly because of the higher density of the mud.

Vlad quickly hit a layer of nice clay, so he didn't need to resort to drilling mud. It was supplied by nature. Lucky guy!

So ultimately, you'll just have to build your equipment as best you can and give it your best shot, but be prepared to encounter unexpected results and have to modify your approach to fit the circumstances.

If you really do have deep sandy clay soil, it is the best soil to drill through with a light weight drilling rig such as you are putting together.

But I have to say that Vlad really understands the need of a robust fluid pump.

But any way you look at it, a 150 foot hole is a real achievement.

And you have a guaranteed adventure ahead of you.

Remember the safety thing.

Best,

-AC

[DavesPlanet]

hmmmm... I'm really starting to think I might be quite happy with two x 75' per ton, that's certainly nothing to sneeze at. Thanks guys!

[jdrimm]

Does anyone have experience with the so-called "baptist" method of drilling? The claims I have seen indicate depths right around 200', but I'm concerned about real-world performance.

I apologize if this has been covered, but I can't seem to use the thread search function on my tablet, and don't have any other way to get online right now.

[mejunkhound]

If you have any rocks bigger than 2-3" it will not work. Fine in sand or clay though.

If you have rock, the same type setup but with percussion bit and a bailer will work, but takes a LONG time by hand.

There are 1000 ft deep wells in China done by bail and percussion BY HAND (e.g pull the rope, let it drop, repeat), but they tooks literally generations to drill, talk about persistence.

See post #30 for a DIY percussion rig and one before that for the even the time needed for a mechanized percussion diy rig.

[jdrimm]

Originally Posted by mejunkhound

If you have any rocks bigger than 2-3" it will not work. Fine in sand or clay though.

Well, my part of Kentucky is clay with random limestone inclusions, so that sends me back to rotary methods. Thanks!

[AC_Hacker]

Originally Posted by jdrimm

Does anyone have experience with the so-called "baptist" method of drilling? The claims I have seen indicate depths right around 200', but I'm concerned about real-world performance.

Funny that you should ask...

I tried many drilling methods, and the Baptist method was one of them.

(If you did an advanced search through the 'geothermal and heat pump' series of posts, and look for Baptist, you'd find my posts)

Don't know if you have looked, but there are videos on youtube showing how it's done.

Yes it works and I was able to punch through soil formations that were impossible using the other methods I was trying.

The method was developed to be a drilling technology that could be replicated in remote villages throughout third-world countries, where machine shop technology and gasoline powered tools were not available. To my way of thinking, it is an absolutely brilliant solution to a very serious problem.

In the Youtube videos, you will see that a whole village gets involved, taking turns pulling the rope that lifts the drill stem, and also adding additional speed to the drill stem as it falls. When I tried it, I came to the crushing realization that I was not a village.

But if you got a bunch of friends together, and a keg, and made a party of it, well... you'd have a village, and everybody would get muddy and a bit smashed and have a great time.

You might even be able to do a gasoline-powered version of a whole village.

The key to the Baptist method is that it combines the characteristics of the percussion drill and also the 'bailer' which is used to lift cuttings out of the hole... so drilling and bailing are both done at the same time. Pretty cool.

I can't answer your concern about limestone inclusions, but the spear-like point of the Bapsist drill focuses a lot of force onto a small point, and the blades of the point are there to further pulverize and displace obstacles.

So, bottom line, if you are permanently short on financial and technical resources, it might be a good way to go... you'd have to be patient, as progress would be gradual.

On the other hand, if you can afford it, power is your friend.

Vlad build a truly amazing machine, which I had the privilege of seeing it in operation, and also, mejunkhound built a spectacular rig too, although I never got to see it work. I wish mejunkhound would start a thread on exactly how he built his rig, because it was pretty awesome.

Best,

-AC