Key points of water finding technology using ground water detector drilling

The well is the smallest water project since ancient times, yet it is a special water project involving multiple disciplines. One of its characteristics is the universality of its use. Whether it is a large amount of farmland irrigation, or a large number of small and medium-sized enterprises, most of them rely on wells to provide water, almost no well is not unrelated to the units and individuals; second is the hidden nature of the project. How the quality of the well is difficult to detect, once the quality of the problem can not be remedied; third is the high risk of investment. Drilling a dry eye is a large number of things, if not scientific, blindly drilling wells, most places fail more than success. Once there is no water, thousands of dollars to tens of thousands of dollars of investment will have been wasted. In this sense, the well is one of the highest risk, the most failed water conservancy projects; fourth is the complexity of technology. Generally believe that drilling a well is "drill a hole, down a tube", seemingly simple, the actual technical content is very high, involving hydrogeology, physical prospecting to find water, well technology, pump selection and other aspects of knowledge, is often not paid attention to, it is easy to fail more, poor quality, high risk problems. Although the learning of drilling wells to find water is very deep, but if the person has some scientific knowledge to reduce blindness, or a great benefit.

A. To study in detail the local hydrogeological conditions. If you do not understand the hydrogeology, do not study the hydrogeological conditions, but only believe in ground water detector, measured points everywhere, can only be called "blind test". The following three aspects can be investigated and studied.

1. Study the topography and geomorphology. Topographic and geomorphological conditions determine the groundwater recharge runoff drainage conditions, control the weathering of the rock, affecting the groundwater abundance changes. To build reservoirs to have a watershed area, drilling wells also need to have recharge area, the same reason. 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 where groundwater is not good.

2. Study the water-richness of rocks. 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, when hit with a hammer, the feeling of some hair "burgundy" (rigid), some hair "sheep" (flexible), some hair "brittle" (brittle), brittle rocks and limestone, etc. Soluble rocks are more likely to form wells.

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

B. To choose the suitable local geological conditions of the physical prospecting water search method

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. There are many specific methods, commonly used are duplex electric survey method, high-density electric survey method, vertical electric sounding, 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. After years of water search research by our institute, the more interfering factors in the poor water area, the use of our company's self-developed ground water detector to find water on the aquifer is the strongest, much better than any other methods.

C. To use a 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, the longest service life, the well formation process is scientific and reasonable is essential.

1. The filter pipe should be right on the aquifer. Once the two are misaligned, the water inlet resistance is much greater, increasing the depth of descent. For this reason, we have to conduct physical exploration of the well before placing the pipe to accurately determine the aquifer site.

2. The opening rate of the filter water pipe should be sufficient. No matter what pipe opening rate can not be less than 10%. Most of the cement pipes produced by indigenous methods are only 1-2%, which is not allowed because of the great resistance to water intake.

3. There should be bedding bars between the filter pipe and the filter screen. If there is no pad tendon, the filter net clings to the well pipe, and only the mesh of the water inlet hole can be fed, which will easily cause blockage and seriously affect the water output and service life of the well.

4. Screen mesh and fill gravel size to adapt to the aquifer. Otherwise, it will either block water or cause muddy water in the well.

5. Using mud drilling, before the pipe to break the wall for slurry.

The current society drilling wells commonly exist arbitrary configuration of filter water pipe, filter water pipe opening rate is too low, not add the mat tendons, filter network and fill gravel is not qualified, break the wall for slurry is not complete and other serious problems, need to be improved. This is an important reason why most of the recharge wells of ground source heat pump are not well recharged. Our company has developed a set of drilling construction procedures for the above-mentioned problems of professional drilling teams, and the drilling effect is very good whether it is positive circulation or reverse circulation.

D. Pumping test should be conducted and pumps should be reasonably matched

The pumping test can be combined with well washing. Before the end of the well washing, we should measure the water output of the pump, the static water level, the dynamic water level, and calculate the unit water output of the well, the maximum possible water 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 our experience, as long as the above work is done, the success rate of well drilling and pumping energy saving rate on the existing basis to increase 20-30% is very easy to do, if it can be popularized in the country, the potential is huge.