Application of Air DTH Hammer Drilling Technology in Geothermal Deep Wells

As an efficient and economical drilling method, air down-the-hole hammer drilling technology has been increasingly widely used in geothermal deep wells in recent years. This technology has become a vital method for developing geothermal resources due to its rapid drilling speed, low costs, and effective aquifer protection. However, with the continuous increase in the drilling depth of geothermal wells, traditional drilling technology faces many challenges, such as low drilling efficiency and frequent complex formation problems. Especially in sedimentary rock formations, air down-the-hole hammer drilling technology should overcome the difficulties of deep formation, leakage, water gushing, and collapse. Therefore, an in-depth study of the application of air down-the-hole hammer drilling technology in geothermal deep wells is of great significance to improving the efficiency of geothermal resource development and reducing development costs.

Principle of air down-the-hole hammer technology

Air down-the-hole hammer drilling technology is a technology that uses compressed air to drive the down-the-hole hammer for drilling. During the drilling process, high-pressure air enters the inside of the down-the-hole hammer through the drill pipe, driving the impact mechanism inside the down-the-hole hammer to generate high-frequency and high-intensity impact force, which directly acts on the drill bit to achieve the crushing and drilling of the formation. At the same time, high-pressure air can also bring broken rock cuttings out of the hole, keep the hole clean, and improve drilling efficiency.

Technical advantages

• Efficient drilling: air down-the-hole hammer drilling technology breaks rock formations using high-frequency, high-intensity impact forces, significantly enhancing drilling efficiency. Compared with traditional methods, its drilling speed can be several times faster or even dozens of times quicker.

• Low drilling cost: with its fast drilling speed and short construction time, air down-the-hole hammer drilling technology can significantly lower drilling costs. Additionally, this method causes less wear on equipment and has relatively low maintenance expenses.

• Good effect in protecting aquifers: during the drilling process, high-pressure air can effectively bring rock cuttings out of the hole, avoiding pollution and damage to the aquifer. It is of great significance for protecting geothermal resources and improving water quality.

• Strong adaptability: air down-the-hole hammer drilling technology is suitable for many formation conditions, especially for those complex formations that are prone to leakage, water gushing, and collapse, and its drilling effect is particularly significant.

Application Cases

In a geothermal well project, the air down-the-hole hammer drilling technology successfully achieved a breakthrough in the depth of sedimentary geothermal wells, with the drilling depth reaching an astonishing 2,250 meters. This project verified the feasibility of air down-the-hole hammer technology in deep well drilling and provided valuable experience and data support for the deep development of geothermal energy.

The project utilized air drilling technology to construct the entire well. By carefully designing the well structure, selecting high-performance tools and equipment, and effectively managing the working air pressure and supply, the drilling operation proceeded smoothly. Throughout the process, the project team faced challenges like complex formations and high water output but ultimately completed the drilling task and conducted a pumping test, achieving excellent water output and temperature data.

Scientific Regulation of Working Air Pressure and Air Supply

The successful application of air down-the-hole hammer drilling technology is inseparable from the scientific regulation of working air pressure and air supply. Working air pressure not only influences the impact force and crushing effectiveness of the down-the-hole hammer but also directly impacts the capacity for carrying and discharging rock cuttings. The air supply volume is crucial for ensuring the effective removal of debris from the borehole, which directly affects drilling speed and the stability of the hole wall.

Conclusion

With the continuous development and utilization of geothermal energy, air down-the-hole hammer drilling technology will play an increasingly important role in the field of geothermal deep well drilling. With the continuous advancement of technology and the deepening of application, air down-the-hole hammer drilling technology is expected to be widely used in more geothermal projects with complex geological conditions and high drilling depth requirements, further promoting the development and utilization of geothermal resources and contributing to the realization of green and low-carbon development.