In many regions, when it is impossible to connect to a centralized water supply, they resort to drilling water wells from underground horizons.
Groundwater isolated from surface sources of pollution by rock strata
, as a rule, meets sanitary standards established for domestic water. With additional cleaning, passing through the filter device, they acquire high quality drinking.
What you need to know
The determining criteria for choosing a method of drilling a water well are the depth of the groundwater level and the rocks of the geological section, which are to be drilled. Properly selected technology for drilling water wells will allow you to quickly drill a well, to avoid accidents during drilling. As a result, this will make it possible to obtain the highest flow rate of the
water intake structure under the given conditions
.
What does water well drilling technology mean? This is the method and mode of destruction of various rocks, cleaning the wellbore and fixing its walls, equipment of the water intake part.
Drilling methods
For the construction of deep water wells, rotational and shock-rope drilling is usually used. The technology for drilling water wells with these methods is different. The features of each do not allow their use without restrictions in any conditions. The technology for drilling water wells with a drilling rig with the rotation of a rock cutting tool (chisel) in this article is given by the example of screw and rotary methods.
Auger drilling technology
In sandy and clayey rocks that do not contain large inclusions, drilling is used with a set of chisels and screws transporting the rock to be drilled from the bottom to the top. Of the two varieties of auger drilling, a continuous face, continuous penetrations, and screwing are most often used for installing a water well in an area with a well-studied geological structure. Where it is necessary to obtain high-quality information about the rocks and their depth, the method of annular slaughter is used.
Continuous flight (in-line drilling) - drilled rock is carried out by a screw column to the surface. As the drill hole deepens, it grows with additional augers. They are used for driving homogeneous sand without layers of silt or other weak rocks. The frequency of rotation of the screws 250-300 rpm It is unacceptable to immerse too quickly in order to avoid overflow of the blades with rock and jamming of the projectile in the well for this reason. Adequate load - dead weight and rotor weight.
In plastic and refractory clay rocks, rails are used - a bit and a screw column are drilled into the rock with subsequent extraction to clean the flanges from the drilled mass. The size of the route dive within 1 meter. Rotational speed from 100 and not more than 300 rpm. Load 500 N.
In weak rocks, a spiral chisel on a screw column is used - they are screwed to a certain depth and then removed without rotation by a winch.
The annular face is carried out by special core augers, which make it possible to extract a core (drill string) without raising the drill string to the surface. Drilling mode: 60-250 rpm, the value of the flight is from 0.4 to 2.0 m. This technology of drilling wells for water is rarely used, mainly by geological organizations involved in exploration and simultaneously drilling wells for water.
Rotary Rotary Drilling Technology
In this way, a high penetration rate and large outputs of pipe columns are achieved. The disadvantages include the mudding (claying) of the aquifer, the high cost of preparing a clay solution, large volumes of water for flushing the well to restore the water loss of the horizon, which has become obstructed during drilling.
Rotary with direct flushing is more often used: the destroyed rock from the bottom is brought to the surface by a clay solution pumped into the well by a pump through drill rods. It is necessary to withstand upstream speeds in the range of 0.5 - 0.75 m / s. The circulation of the washing solution is disturbed in highly fractured zones - it goes into the cracks together with the sludge. The driller needs to carefully monitor the drilling mode, reduce axial load if necessary, and flush without interruption in order to avoid sticking the projectile.
There is no need to pursue the high mechanical speed achieved by increasing the speed: this is fraught with accidents. The load on the bit and rotational speed are regulated depending on the type of rock passed, the diameter of the bit and drill pipe, and the amount of flushing fluid.
Turnovers should be reduced with:
- bit parameter increases;
- reducing the diameter of the drill string;
- increase rock strength;
- when alternating layers with low power (up to 1.5 m).
On rotary units such as URB and BA, they operate mainly at II-III speeds. Clay and clay-sandy rocks are drilled at 300-400 rpm (III-IV speeds). For rocks of moderate strength (sandstones, limestones, marls), the rotor rotation limits are from 200 to 300 rpm. Strong rocks are drilled with a bit with a rotation speed of 100-200 rpm.
The driller carefully monitors the drilling mode, reducing the axial load and continuously flushing to avoid sticking the projectile. The moment of opening of the aquifer determines a sudden decrease in clay mud and an increase in engine load. The circulation of the solution is disturbed in highly fractured zones - the cuttings and the solution go into cracks.
If the aquifers are represented by indigenous with small cracks, the opening of the horizon is carried out with a high-quality clay solution with its obligatory exit to the surface.
The technology of drilling water wells with a small drilling rig is similar to the technology of drilling with powerful machines.
Related work
Fastening the walls of the well with pipes is carried out after drilling. Apply metal, asbestos-cement and plastic pipes. The type of filter (hole or mesh) is selected depending on the water-bearing rocks.
Before installing the filter, the solution is replaced with a lighter one, a specific gravity of not more than 1.15 is desirable. After installing the filter, immediately wash the well with water. Then, the well’s geloning is carried out - pumping out a column of liquid from the well by the chasing. With clarification of the washing and the appearance of sand in it, pumping starts with an airlift. With the cessation of sand removal and complete clarification of the water, a submersible pump is installed.
Energy of a free-falling blow
Shock-rope method reveals low-power aquifers (less than 1 m) without any problems. It is possible to obtain the maximum flow rate - water-bearing rocks are not clayed. No long pumping time needed.
The method is used:
- in poorly studied terrain;
- in anhydrous areas where it is impossible to deliver water for the preparation of a solution;
- if necessary, separate testing of several horizons;
- for wells with a large initial diameter.
Disadvantages of shock-rope drilling:
- low penetration rate;
- high consumption of pipes for casing;
- limited drilling depth (up to 150 m).
The normal impact frequency of a free-falling projectile is calculated. It is inversely proportional to the square root of the fall height: with an increase in the height of the bit rising above the bottom, the frequency of impacts is reduced and, conversely, with a decrease in height, the number of impacts is increased.
Need strength and savvy
With a shallow groundwater table (usually groundwater) and a geological section composed of loose rocks, in the
cramped conditions of the built-up area, a well can be drilled using the muscular power of people - 2 people are enough.
Manual water well drilling technology is simple. You can apply the driving method or screw.
To hammer a steel pipe with a diameter of 1 inch, it is previously cut into pieces of 2 or 3 meters. At the ends, an external thread is made. As they deepen, the pipe sections will be connected by couplings with an internal thread. A special steel tip (shank) is made in the form of a cone, the diameter of the base of which is 1 cm larger than the diameter of the pipe. It is welded onto the pipe. About a meter of the length of the pipe above the tip (60 cm is enough) is reserved for a primitive filter - a water receiving device for penetrating water into the well from an aquifer. A 6 mm drill makes holes 5 cm apart.
A clogging device of two separate parts is put on the pipe. The first is an emphasis with a conical hole under the pipe. Its outlet is 5 mm larger than the external diameter of the driven pipe, which is enough to insert two wedges into the gap from below - a metal truncated cone cut along it. The diameter of the top of the cone is slightly larger than the diameter of the pipe, but smaller than the outlet of the stop. The second part - shock "woman", a cargo with a through hole for the pipe and two handles for lifting above the stop.
When lowering the woman at the moment of her impact on the stop, the wedges enter the hole and hold the hammered pipe in their "arms". After driving the pipe section, the cone is knocked out, the pipe is extended, screwing up with the next section. Rearrange the emphasis with wedges, put on a "woman" and continue to clog the pipe to the aquifer. Periodically, you need to rotate the pipe around the axis.
The appearance of water in the well is determined by lowering in its weight, tied to twine. If it is lifted up wet, then the well has sunk into the aquifer. It is important not to “slip through” this layer, which gives water. Leave the perforated end of the pipe in this water-saturated rock. And to begin pumping the mini-well first with a hand pump. As water clarifies, it is transferred to pumping by a surface water electric pump.
Auger manual drilling of wells for water - the technology is similar to that described using a drilling rig, which is replaced by two people. Of course, they cannot keep up with the parameters of the mechanical drilling regime. Some craftsmen replace physical strength with mechanisms.
Water well drilling
The technology is simple with minimal material, effort and time. Conditions - well depth up to 10 m, the section is composed of loose soils.
Equipment - a pump "Baby", a capacity for water (the larger the volume, the better, but you can also a barrel of 200 liters). The gate for turning the pipe is made of two pipes and a coupling clamp.
Materials: a pipe with a diameter of 120 mm, a length to the depth of the well. The teeth are cut at the lower end, the upper end is equipped with a flange with a fitting through which water will flow through the hose from the barrel under the pressure created by the "Kid" pump. For fastening the flange to the pipe edge, 4 tabs with holes for M10 bolts are welded.
Workforce: easier to work together. Time expenditures - for 6 meters of loam drilling for 1-2 hours.
Drilling process: dig a pit about a meter deep, install a pipe vertically in it and pump water into it. Water coming out through the lower end with incisors will begin to erode the soil, freeing up space under the pipe, which will settle under its own weight. It is only necessary, swinging, to turn the pipe so that the teeth crumble the rock. Drilled rock particles under pressure exit together with water into the pit. Water can be scooped out of it and, strained, reused for washing. Having reached the aquifer, the flange is removed, and a pump is pumped into the borehole under the water level, but not reaching the bottom hole.
Types of water wells
They are divided into filterless and filter. Filterless wells are arranged in aquifers composed of fine-grained sands or in stable fractured rock formations. For other aquifers, a filter is selected depending on the fractions of the water-bearing rocks.