Activities aimed at eliminating the water intake are called cementing or grouting of the well. Such work is carried out in order to protect the aquifer from possible chemical or bacteriological pollution from the surface. Well plugging is translated from French “cork”.
This term indicates that in the process of work, a solution is injected inside, which strengthens the rocks, forming an anti-filtration and waterproofing curtain. Liquidation plugging is carried out when the well has failed, this can happen for various reasons. The main ones are the following:
- the source fulfilled its purpose;
- not claimed or abandoned;
- geological reasons;
- technical reasons;
- environmental or technological reasons.
Description of the types of grouting
If we examine the geological causes in more detail, we can say that in this case the water intake can simply cease to fulfill its role, which quite often becomes a consequence of geological processes. Technical reasons - this is the case when the water intake for a long time was not maintained in working condition.
An alternative is the violation of technical standards during drilling. The work could be carried out using inappropriate materials, for a long time the repair was not carried out, and the service was not carried out. Well plugging is also carried out when the water intake was built for temporary use.
Reasons for the elimination of water withdrawal
If the well fits one of the categories listed above, then it should be eliminated, because there is a possibility that the aquifers will be contaminated, and they can be used by other intakes. After reviewing the "Law on Subsoil", you can find out that the user must ensure the elimination of the source and the safety of the water intake.
Work Rules
When performing grouting, specialists should use the rules of liquidation grouting of wells; they suggest the need for design work. At this stage, you should find a passport that contains information about the type of protective structure, it can be a building, coffer or pavilion. In the documents you can find the parameters and characteristics of the water intake unit, as well as the absence or presence of underground tracks.
Next, you need to carry out a study called logging. As a result, it will be possible to determine the depth of the well, to assess the condition of the casing string, and more precisely, the walls. All this can be called a revision of the source. The plugging of an artesian well must necessarily be accompanied by a determination of the cause, then the elimination category is assigned.
A two-meter pit is dug around the source perimeter, the width of which should be 1 m. Casing should be cut 30 cm above the bottom of the pit. Drilling equipment will clear the source of foreign objects and trash.
Technology of work
The rules for liquidation cementing of boreholes provide for the disinfection and washing of the water intake with special solutions. The filter column should be covered with gravel or crushed stone to the full depth. Next, a cement mortar is prepared and poured . If the water intake has an impressive depth, backfilling and cementing can alternate.
Using cement, the mouth is poured, then the stub is brewed. Liquidation grouting of wells involves backfilling of crushed stone pillows. It should be 50 cm below the surface of the earth. The top layer can be formed by fertile soil or poured with concrete, everything will depend on the purpose of further use. The final stage will be the survey of water intake from the register.
When killing is required
They muffle a well when an aquifer begins to gush. For this, the bottomhole pressure must be increased so that the in-situ pressure indicators are exceeded. If a 5-meter fountain is blocked from a source, high-density technical fluid should be pumped into it. The total mass in this case should create a pressure higher than that noted in the aquifer.
Jamming will eliminate the accident and eliminate its consequences, eliminating the risk of relapse. After the repair is completed, the technical fluid is pumped out, flushing is carried out, only after the source can be used again. Sometimes jamming is carried out tightly, in this case the well will no longer be used.
Such well plugging may involve the use of a chemical or biological agent, in which case the source will not be suitable for operation. As an alternative solution, cement mortar can also be used. Sometimes seasonal stunning is also required, in which case water is drained from the system and the caisson is insulated. This kind of event is carried out in summer cottages.
Liquidation of wells for various purposes
The rules for liquidation grouting of wells for various purposes involve the use of different techniques. For example, if the well turned out to be dry, then it can be poured with a clay solution or cast with clay to the full depth. Engineering-geological, hydrogeological, mapping and geological-exploratory wells that have already fulfilled their purpose and also have not yielded positive results can be eliminated by casing extraction.
If after completion of work it is not possible to carry out such manipulations, then the wellbore should be covered with clean sand, and the overlying part should be cast with clay, and filled with clay or cement mortar. The liquidation grouting of wells for various purposes in this case involves compliance with the requirements of the sanitary and epidemiological service.
According to them, wells and workings are subject to plugging, which have existed for quite some time. They may be inactive, silted up, or clogged. In this case, the flushing can be carried out with a mud or water using a drilling tool. Then the well is filled with chlorinated water, the volume of which should be equal to the triple volume of the wellbore.
If the water intake is within the aquifer, then it should be filled with clean sand, the volume of which should be equal to the volume of the wellbore within the aquifer. The upper part is filled with clay mud, cast with clay and rammed, as an alternative solution, cement mortar can be used.
Liquidation of an artesian well
The plugging of an artesian well may involve the use of clay and tampons. To do this, apply fatty clay, in which there are no extraneous impurities. Why it is mixed with a mixer, and balls are rolled from the resulting rock, the size of each of which should be equal to the fist.
The balls are dried, for this they should be left in the sun. Then they are put into production 15 pieces at a time. Sometimes the balls are lowered inward with the help of a chipper, at the end of which there should be a valve opening outward. If this method is used, the balls are not pre-dried. Each portion is well condensed, at the same time the pipe rises. The cork height should be 1.5 m.
The second way to eliminate artesian wells
Well plugging of artesian-type wells can be carried out using concrete mortar prepared using special technology. Some believe that the first method is not so relevant. However, this statement is erroneous. After all, sometimes temporary plugging is required. But if the well will no longer be used, then its liquidation should be carried out with concrete. When the water intake needs to be divided into sections for a while, use swabs called packers. They are used in the study of rocks that differ in the presence or absence of pores and cracks. Thanks to them, you can check the quality of cementation of rock.
Conclusion
For the tamponing you will need certain equipment, this is a metal tamper, a pump and drill pipes. A pump will be required to pump cement with drill pipes, which will be lowered to the bottom.