The drilling of a well
What is an artesian well ?
An artesian well is obtained by piercing a water proof layer of the ground to reach a groundwater reserve under pressure. Drilled wells are not all artesian wells but the use wanted the name of artesian well to be used to designate all drilled wells that draw water from the depths of the earth. The artesian well is either supplied by water that is circulating through the veins (fractures) in the roc, or by the water present in the gravel or sand under a layer of clay. The artesian well is usually dependable and stable all year round when it comes to the quantity of water. On Earth, groundwater is far more abundant than soft surface water. In Quebec we can find groundwater nearly everywhere.
Besides its dependability, the artesian well is the option of choice because it is less vulnerable to bacterial contamination than a surface well or than taking water from a water source. When the drilling and the pump installation are completed according to the rules of art, infiltration of surface water in the well should be less than none, which favors the water’s purity all year long.
What kind of drill do we use ?
The equipment that we use is a rotary drill (rotary-hammer). Drilling by rotation alone is being more and more replaced by machines that hammer the bottom of the hole with a pneumatic hammer while drilling by rotation, where comes the term rotary-hammer.
This machine is powerful and its primary advantage resides evidently in the fact that it can advance at high speeds especially in roc. Its cost is inferior to a cable machine and it can reach further depths. This can be explained through the following : water mixed to dust from the roc, combined with the fast rotation of the drill can form a glaze on the edges of the well. This technique has undoubtedly the technological advantage and largely dominates the market.
How do we drill the well ?
During the drilling, a mix of air and water under pressure are sent in the well to extract the debris caused by the drilling activity. Then, we enter a steel pipe (casing) in the well that is used to prevent the crumbling of the hole in soft soils and to block water cavities of bad quality that we came across during the drilling. When we hit solid roc, the casing is not necessary but, we will have to seal the joint between the casing and the roc with a pile sink shoe.
It is very important that you are present on the construction site during the work. You can also be represented by someone that will see to the supervision of the driller’s work and will be able to give you expert advice when faced with certain problems encountered along the way. Important decisions may have to be made during the drilling of the well and they must be taken by you.
Don’t forget that a well constructed well with a sufficient water reserve and of good quality is worth a bucket of gold. Furthermore, remember that the master of well drilling is your driller.