Drilling of wells to find groundwater sources

A. To study the local hydrogeological conditions.

If you do not understand the hydrogeology, do not study the hydrogeological conditions, only believe in the instrument, measurement points everywhere, can only be called "blind test". Research can be done from three aspects.

1, topography and geomorphology

Topographic and geomorphological conditions determine the groundwater recharge runoff drainage conditions, control the weathering of the rocks, affecting the changes in groundwater abundance. Build reservoirs to have a watershed area, drilling wells also need to have recharge area, the reason is the same. If the lithological conditions are the same, low-lying terrain or terrain conducive to water catchment is more likely to become a well. However, some small plains and depressions are often dominated by muddy rocks underneath, which can easily be weathered and denuded to form lowlands, and the groundwater is not good.

2, the water-rich nature of the rock.

Rocks can be divided into igneous rocks, metamorphic rocks, sedimentary rocks according to the genesis of the three categories, and then subdivided very complex. Regardless of the genesis, the feeling when hit with a hammer, some hair "burgundy" (rigid), some hair "sheep" (flexible), some hair "brittle" (brittle), brittle rocks and limestone, etc. Soluble rocks are more likely to become wells.

3, the fracture development of the rock.

Fractures are more developed near the fracture zone. Inclined rocks are easier to develop fractures than horizontal rocks.

B. Select the suitable local geological conditions of physical prospecting water search methods

At present, the main method of physical prospecting to find water is electrical exploration. Electrical prospecting methods are divided into artificial electric field method and since (natural) natural electric field method. Many specific methods, commonly used are duplex electric survey method, high-density electric survey method, vertical electric bathymetry, four-pole symmetric profile method, joint profile method, excitation polarization method, etc., each method has its own applicable conditions and interference factors, must be selected according to local conditions.

Underground Water Detector Product Recommendation

PQWT-S150.150M Underground Water Detector

PQWT-S300.300M Underground Water Detector

PQWT-S500.500M Underground Water Detector

PQWT-TC700.600M Underground Water Detector

PQWT-TC900.1200M Underground Water Detector

PQWT-GT Auto-analysis Geophysical Detector

We recommend pqwt's natural electric field ground water detector, which is the eighth generation multi-channel electric exploration instrument based on the principle of natural electric field frequency selection method newly developed by our institute, and is widely used in the exploration and census operations in the fields of ground water source, geological structure, mineral veins, mining channel, cavity, cavern, anthill, mining area, dike pipe surge, landslide and so on.

This series of instruments integrates five patented technologies of pqwt independent invention, including data acquisition system, data processing system, automatic map-forming system, auxiliary analysis system and circuit system. It truly realizes multi-channel and multi-frequency data acquisition simultaneously and synchronously, which completely solves the influence of unstable factors brought by the natural electric field source due to the time difference, and greatly improves the accuracy and work efficiency. The instrument processes the collected data in real time, automatically draws curve, profile and 3D effect map in real time, and automatically analyzes the abnormal area, so as to provide scientific basis for analyzing the geological structure quickly and effectively.

C. Adopt scientific and reasonable well formation process

In the same geological conditions to make the maximum water output, the minimum depth of drop, the best water quality and the longest service life of the well, whether the well formation process is scientific and reasonable is crucial.

1、Filtering water pipe should be facing the aquifer

Once the two are misaligned, the inlet water resistance is much larger, increasing the depth of descent. For this reason, before the tube to carry out physical detection well, accurately determine the aquifer parts.

2, the filter water pipe porosity should be sufficient

No matter what pipe open porosity can not be less than 10%. Most of the cement pipes produced by indigenous methods are only 1-2%, and the water inlet resistance is very high, which is not allowed.

3, filter water pipe and filter mesh should be padded tendons between

If there is no pad tendon, the filter net clings to the well pipe, and only the mesh facing the water inlet hole can be fed, which is very likely to cause blockage and seriously affect the water output and service life of the well.

4, the mesh and fill gravel size of the screen to adapt to the aquifer

Otherwise, either blocking water or muddy water caused by the well.

5、For mud drilling, the wall should be broken and replaced before the pipe is lowered.

The use of mud drilling, before the tube to break the wall for slurry.

At present, there are serious problems such as arbitrary configuration of filtering water pipes, low opening rate of filtering water pipes, no reinforcement, unqualified filtering network and gravel filling, and incomplete wall slurry replacement, which need to be improved. Most of the recharge wells of ground source heat pump are not well recharged which is an important reason.

D. To carry out pumping test, reasonable matching pump

Pumping test can be combined with well washing. Before the end of the well washing, we should measure the water output of the pump, static water level, dynamic water level, and calculate the unit output of the well, the maximum possible output and the appropriate amount of water for the pump. At present, the majority of wells do not have the above data, only know a few kilowatts of water pump enough to pump, can only be a blind choice of pump, well drilling how deep to choose a high head of the pump, a serious waste of energy.

According to experience, as long as the above work is done, the success rate of well drilling and pumping energy saving rate on the basis of the existing 20-30% is very easy to do.