Generally, the place with sufficient water is 10 to 30 meters, as well as water and shallow wells. The water there is not enough to hit hundreds or even hundreds of meters, which is a breakthrough layer. This is a deep well. Deep well water quality is good, but drilling cost is high. Generally, domestic water with sufficient local water quality can fetch several meters.
People in China have long been used to using circular barrel wells, with a diameter of1~ 2m and a depth of several meters to 20 ~ 30m. During construction, people can directly enter the bucket to dig earth and stone, and this kind of well is only suitable for mining shallow groundwater.
The correlation is as follows:
In order to exploit deep groundwater, tube wells with small diameter and considerable depth have been developed, which requires special drilling machinery and complex technology.
As early as 250 BC, in China's present Sichuan Province, a large number of wells tens of meters or even 100 meters deep were dug in hard rocks to exploit underground brine to cook salt.
After drilling a well to expose the confined aquifer containing brine, the groundwater often flows out of the well by itself, which is the artesian well, hence the name China Sichuan artesian well.