Main Steps and Procedures of Well Drilling

Main Steps and Procedures of Well Drilling

Well drilling is a systematic project. Its core objective is to find a stable and sufficient water source underground and safely and effectively bring it to the surface for human use. The entire process can be clearly divided into several key stages, each interconnected. The standardized operation of each stage directly affects the quality and lifespan of the final well.

All work begins with meticulous construction preparation and site layout. Before the equipment arrives, the construction team will accurately determine the well location according to the design drawings and clear and level the site to ensure the drilling rig has a stable working platform and sufficient turning space. Simultaneously, they will plan the mud pit (for storing and circulating cooling mud and water carrying rock cuttings), material storage area, and safety passages. Various equipment, such as the drilling rig, mud pump, and drill rods, will be transported to the site in an orderly manner and inspected and installed, laying a solid foundation for the formal drilling commencement.

After preparation, the core drilling and hole formation stage begins. The drilling rig starts, and the drill bit begins to rotate or impact, breaking down the rock and soil. As the borehole deepens, operators need to assess the formation's hardness based on vibrations, sounds, and the rock cuttings carried up by the drill bit, adjusting parameters such as pressure and rotation speed accordingly. To maintain borehole stability, cool the drill bit, and remove drilled rock cuttings, a mud pump continuously pumps prepared mud (or water) into the borehole, creating a circulation. Drilling is considered complete only after the drill bit reaches the predetermined depth and it is confirmed that the target aquifer has been penetrated.

After drilling, the "skeleton" of a well is established, followed by the more detailed stages of casing installation, gravel filling, and well completion. Workers carefully lower the pre-connected well casing (usually a filter pipe with perforated holes) vertically into the center of the borehole. Then, the annular space between the casing and the borehole wall is filled with sifted, uniformly sized gravel (called filter media). This filter media acts like a natural filter, preventing fine sand from the aquifer from entering the well and clogging the water pipes, while ensuring the smooth flow of groundwater into the well. After this step, a powerful and thorough well-washing process is performed using a piston, air compressor, or water pump to remove mud and fine particles from the well and surrounding aquifer until the returned water is clear and transparent, and the well's water output stabilizes.

Finally, the equipment installation and acceptance phase begins. Depending on the requirements, a suitable water pump (such as a submersible pump) is installed at the wellhead, along with a well platform, well cover, and other protective facilities. The construction team, together with the owner, conducts a formal pumping test, continuously pumping water for a period of time to accurately measure the well's stable water output and water level drop, and collects water samples for quality testing. Once all indicators meet the design requirements and contractual agreements, a qualified well is officially handed over for use, and a complete construction record report is submitted to provide a basis for future maintenance. This entire process spans the entire chain from ground positioning to successful water extraction, demonstrating the close integration of engineering technology and geological knowledge.