In many regions, if 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 masses, as a rule, meets the sanitary standards established for domestic water. With additional purification, passing through the filter device, they acquire high drinking quality.
What you need to know
The determining criteria for choosing a method for drilling a water well are the depth of the groundwater level and the rocks of the geological section that are to be drilled. The right technology for drilling water wells will allow you to quickly drill a well and avoid accidents during drilling. As a result, this will make it possible to obtain the highest flow rate of the water intake in these conditions.facilities.
What does the technology of drilling wells under water imply? This is a method and mode of destruction of various rocks, cleaning the wellbore and fixing its walls, equipment for the water intake.
Drilling Methods
For the construction of deep water wells, rotary and percussion drilling are usually used. The technology of drilling wells for water in these ways is different. The features of each do not allow them to be used without restrictions in any conditions. The technology of drilling wells for water with a drilling rig with rotation of a rock cutting tool (bit) is given in this article using the example of auger and rotary methods.
Auger drilling technology
In sandy and clayey rocks that do not contain large inclusions, drilling is used with a set of bits and augers that transport the drilled rock from the bottom to the top. Of the two types of auger drilling, for the construction of a water well in an area with a well-studied geological structure, continuous slaughter is more often used with a continuous run, run breaks and screwing. Where it is necessary to obtain high-quality information about the rocks and their depths, the annular method is used.
Continuous run (stream drilling) - the drilled rock is carried out by a screw column to the day surface. As the drill string deepens, it is built up with additional augers. They are used for driving homogeneous sands without interlayers of silt or other weak rocks. Rotation frequencyscrews 250-300 rpm. Unnecessarily fast immersion is unacceptable in order to avoid overfilling the blades with rock and jamming the projectile in the well for this reason. Sufficient load - the own weight of the augers and the weight of the spinner.
In plastic and hard-plastic clayey formations, regular breaks are used - a bit and an auger string are drilled into the rock with subsequent extraction to clean the flange from the drilled mass. The value of the trip dive is within 1 meter. Rotation frequency from 100 and not more than 300 rpm. Load 500 N.
In weak rocks, a spiral bit is used on a screw string - they are screwed to a certain depth and then removed without rotation by a winch.
Annular slaughter is carried out with special coring augers that allow extracting the core (column of drilled rock) without lifting the drill string to the surface. Drilling mode: 60-250 rpm, travel distance from 0.4 to 2.0 m. This water well drilling technology is rarely used, mainly by geological exploration organizations and drilling water wells along the way.
Rotary drilling technology
This method achieves a high rate of penetration and large outputs of pipe strings. The disadvantages include clogging (claying) of the aquifer, high costs for the preparation of a clay solution, large volumes of water for flushing the well to restore the fluid loss of the horizon clayed during drilling.
More often used rotarydirect washing: the destroyed rock from the bottom is brought to the surface by a clay solution pumped into the well by a pump through the drill rods. It is necessary to maintain the speed of the upward flow in the range of 0.5 - 0.75 m / s. The circulation of the flushing 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 the axial load if necessary, and continuously supply flushing to avoid projectile sticking.
Don't pursue the high mechanical speed achieved by increasing the number of revolutions: this is fraught with accidents. Weight on bit and rotational speed are adjusted depending on the formations being passed, the diameter of the bit and drill pipes, the amount of drilling fluid.
Turnover must be reduced at:
- increase in bit parameter;
- reducing the diameter of the drill string;
- increasing the strength of rocks;
- when alternating layers with low thickness (up to 1.5 m).
On rotary units of the URB and BA type, they operate mainly at II-III speeds. The sinking of clayey and clayey-sandy rocks is carried out at 300-400 rpm (III-IV speed). For rocks of moderate strength (sandstones, limestones, marls), the limits of rotor rotation are from 200 to 300 rpm. Hard rocks are drilled with a bit at a rotation speed of 100-200 rpm.
The driller carefully monitors the drilling mode, reducing the axial load and continuously flushing to avoid sticking of the projectile. The moment of opening the aquifer determinesa sudden drop in mud and an increase in engine load. Mud circulation is disturbed in highly fractured zones - cuttings and mud go into cracks.
If water-bearing rocks are bedrock 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 that of drilling with powerful rigs.
Related works
Fixing the walls of the well with pipes is carried out after drilling. Metal, asbestos-cement and plastic pipes are used. The type of filter (perforated or mesh) is selected depending on the water-bearing rocks.
Before installing the filter, the solution is replaced with a lighter one, the specific gravity of not more than 1, 15 is desirable. After installing the filter, the well is immediately washed with water. Then gelling of the well is performed - pumping out the liquid column from the well with a bailer. When washing is clarified and sand appears in it, pumping with an airlift begins. With the cessation of sand production and complete clarification of the water, a submersible pump is installed.
Free-falling impact energy
Thick aquifers (less than 1 m) are opened without problems by the shock-rope method. It is possible to obtain the maximum flow rate - the water-bearing rocks are not clayed. No long pump down required.
The method used:
- in the little-studiedterrain;
- in waterless areas where it is not possible to supply water for the preparation of the solution;
- if necessary, separate testing of several horizons;
- for wells with large initial diameters.
Disadvantages of percussion drilling:
- low ROP;
- 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 drop height: with an increase in the height of the bit above the bottom, the frequency of impacts is reduced and, conversely, with a decrease in height, the number of impacts is increased.
It takes strength and ingenuity
With a shallow groundwater table (as a rule, it is groundwater) and a geological section composed of loose rocks, in the cramped conditions of a built-up area, a well can be drilled using the muscular strength of people - 2 people are enough.
The technology of manual water well drilling is simple. You can use the driving method or screw.
To drive a steel pipe with a diameter of 1 inch, it is pre-cut into segments of 2 or 3 meters. At the ends make an external thread. As the pipes deepen, they will be connected by couplings with internal threads. A special steel tip (shank) is made in the form of a cone, the base diameter of which is 1 cm larger than the pipe diameter. It is welded onto the pipe. About a meter long pipe abovethe tip (60 cm is enough) is reserved for a primitive filter - a water-receiving device for penetration of water from the aquifer into the well. With a 6 mm drill, make holes 5 cm apart.
The pipe is put on a driving device from two separate parts. The first is an emphasis with a conical hole for the pipe. Its outlet is 5 mm larger than the outer diameter of the driven pipe, which is sufficient for inserting two wedges into the gap from below - a metal truncated cone cut along the length. The diameter of the top of the cone is slightly larger than the diameter of the pipe, but less than the outlet of the stop. The second part is a shock "woman", a load with a through hole for the pipe and two handles for lifting over the stop.
When lowering the woman at the moment of her impact on the stop, the wedges enter the hole and hold the clogged pipe in their "embrace". After driving a pipe segment, the cone is knocked out, the pipe is extended, screwing with the next segment. They rearrange the stop with wedges, put on the "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 inside its weight tied to a string. If it is lifted up wet, then the well has gone deep into the aquifer. It is important not to "skip" this layer that gives water. It is necessary to leave the perforated end of the pipe in this water-saturated rock. And start pumping the mini-well first with a hand pump. As the water clarifies, they switch to pumping out with a surface water electric pump.
Auger Manual Well Drillingon water - the technology is similar to that described with the help of a drilling rig, which is replaced by two people here. Of course, they cannot keep up with the parameters of the mechanical drilling mode. Some craftsmen replace physical strength with mechanisms.
Drilling water wells
The technology is simple with minimal cost of materials, effort and time. Conditions - well depth up to 10 m, the section is composed of loose soils.
Equipment - pump "Kid", a water tank (the larger the volume, the better, but you can also use a barrel of 200 liters). The collar for turning the pipe is made of two tubes and a clamp.
Materials: pipe with a diameter of 120 mm, length to the depth of the well. Teeth are cut at the lower end, the upper end is equipped with a flange with a fitting through which water from the barrel will flow through the hose under pressure created by the "Kid" pump. To fasten the flange to the edge of the pipe, 4 lugs are welded with holes for M10 bolts.
Workforce: It's easier to work together. Time spent - for 6 meters of loam penetration 1-2 hours.
Drilling process: dig a pit about a meter deep, install a pipe vertically in it and pump water into it with a pump. Water, leaving through the lower end with cutters, will begin to erode the soil, freeing up space for the pipe, which will begin to settle under its own weight. It is only necessary, while shaking, to turn the pipe so that the teeth crush the rock. Drilled rock particles under pressure come out with water into the pit. You can draw water from it andfiltering, reuse for washing. Having reached the aquifer, the flange is removed, and the pump is immersed into the well under the water level, but not reaching the bottomhole.
Types of water wells
They are divided into filterless and filtered. Filterless wells are arranged in aquifers composed of fine-grained sands or in stable fractured rocks. For other aquifers, a filter is selected depending on the fractions of water-bearing rocks.
