Input from the forum?

[yarg]

Hello Forum Visitors,

I am finishing a project of a small water well drilling machine and would like your input on a couple of options I have in the final make.
Here are my questions of the forum:

1. If you had the choice of having the main drive head powered to 162 RPM at 600 ft lb torque or a 100 RPM head at 750 ft lb torque, which would you want and why?

2. If given a choice between a self priming mud pump able to provide flow to 196 ft of head or a need to prime mud pump able to provide flow to 320 ft of head, which would you prefer and why?

Foot note-------The cost of question one is almost neutral, the cost of the self priming pump is huge ( $1,100 ) , this may change answers?

Thanks to any and all who provide input.

Yarg

 

[Gary Fowler]

I would go for the slower RPM and more torque and the pump would be a no brainer go with the one with the greater head pressure which would allow for deeper drilling. Priming shouldn't be a large issue as long as you have a water tank handy. You could even plumb it in with a valve to a tank and a checkvalve deliver water to the pump till it primed then the checkvalve would keep it from backflowing. I quick disconnect to it would make it less bulky to handle.

 

[SPIKER]

I would say it depends on what you are drilling, Michigan area I'm asuming.

I would say if mostly light soil & gravel to a few feet then sand stone gravels and harder materials intermixed. Then the higher speed to move thru the materials faster and pump with the self priming as the sub surface materials are lighter than heavy granite found out west. Then if the stuff is more gravel and sand the higher torque and higher flow will be needed as the material will want to grab the pipe as it turns and the high flow will be needed to push into the surrounding materials and stabilize the hole as well as bring up the cuttings.

Mark

 

[2458n]

My experience is with a 24x40 vermeer directional boring machine. How deep are you going to go? I do know you want the biggest torque you can get. The rotational speed is important also as it quickly burns things up with out a bunch of water for lubrication. I would go with the pump you have to prime ,but remember frozen water doe not flow and you are going to use alot of water.

 

[yarg]

Thank you all for input.
It is clear that torque is more important than speed. Being inexperienced at the actual drilling aspect, I thought input was in order. I will also be keeping the pump that needs priming as its specs are better and I can acquire it for far less. I rigged a couple valves and a priming funnel system along with a pick pu check valve and in less than one minute, had it primed and running strong. A byproduct of the move to the higher torque motors is moving from 4800 lb hoist to a 5400 lb lift, push force.
I liked the high RPM speed but most units run in the 80 to 120 RPM range so at 100, it should do well.
Around here we have everything from sand to hard rock formations. On the first big test I found going through some large boulders and major rock filled clay, the bit would stall and there was caving due mostly to my inexperienced mud handling. With the original pump capping out at about 37 PSI, keeping good flow was also difficult. Lifting cuts out was not working well. More torque, more PSI and flow= solution?
Gray

 

[SPIKER]

FLOW is more important than PSI in this type of application, however PSI develops do to resistance to FLOW. So if you are seeing a spike in pressure that means cuttings are building up and you need to slow the down speed and let the FLOW flush out the cuttings. You may need to SWAB the hole some (move the head up and down pumping the pipe in and out of the bore to help flush out some large buildup.) You are not digging at that point but the pipe and mud flow helps to get the buildup of cuttings OUT of the hole which will reduce the torque needed. Dropping down close to the bottom but not hitting it is important the flow and increased space taken up by the drill pipe acts like a plunger pumping and moving these cuttings out.

Mark

 

[yarg]

Thanks Mark,

Makes perfect sense. As a roukie, I tend to hurry and that is no good. A few times I had to draw the pipe up the hole to get flow from the pump---just not enough PSI by my estimate. I understand that PSI is not by istself the end all but without it, flow is nothing. This new pump causes a 21 HP engine to dig in so it has both for the rig needs= flow and PSI?

As I have learned, I need about 70 to 90 GPM for a 6 inch bore hole to keep an up hole flow of about 1 to 1.5 GPM. This pump can provide that at 140 PSI.

I have to monitor my mud better and make sure I have good PH. Got lazy on that=bad outcomes I guess, I learn the hard way. Just hard to find people who have information to share on this subject.

Gray

 

[R W]

How about some photos.

 

[yarg]

How about some photos.

I will attach a few pictures of some sub assemblies I have worked on and one of the prototype control panel. Feb. 4 I start the first production run attempt with my two man green crew and I))) They will be made to order as they are not toys and I can not afford to do anything else but make to order
The last design choice I have to make is to use or not use schedule 80 2 inch black pipe for the drill pipe? Many have done so with success but Murphy tends to stay near me

Gray

 

[VAWellDriller]

Just stumbled on this....I'm a mud rotary well driller from VA......nice project. Couple of general comments...with good mud, you can overcome a lot of things....carrying cuttings out of the hole is the first job of mud.....get yourself some bentonite and make a good mixer. Flow is key as well.....don't worry about pressure so much...shoot for an uphole velocity of at least 50 feet per minute...so a 6"hole needs 75 gpm flow. You can get by with less with the right mud though. As for pumps, you can drill a 250 - 300' , 8" diameter hole with a $1000 2" trash pump (honda's are the best). Don't ever push when drilling....you should always be holding back the weight of the drill string. You don't need a lot of speed...go for the higher torque motor. What kind of bit are you using? What kind of drill pipe are you using? Are you digging a mud pit or using a pan?