The diameter and depth of the well depends on the drilling application and the depth of the mineral burial. Drilling oil, natural gas, and groundwater have larger diameters. The main functions are: 1 to obtain underground physical data, that is, take the core from the drilling core, core, cuttings, liquid, gas and so on. 2 As a geophysical logging channel, obtain data on various geophysical fields in the rock deposit. 3 As an artificial channel to observe the hydrogeological dynamics of the groundwater layer. 4 Used as a combination of exploration and mining to develop drilling groundwater, oil and gas, geothermal, etc.
Drilling is usually divided into geological survey or exploration drilling, hydrogeological drilling, water well or engineering geological drilling, geothermal drilling, oil drilling, coal field drilling, ore drilling, building ground drilling, etc.
From drilling to completion, a well needs to perform the following three main tasks: 1. Breaking the bottom rock; 2. Moving the broken rock (ie, cuttings) to the ground; 3. Consolidating the well wall (referred to as cementing).