Current Status and Prospects of Underground Drilling Equipment Technology in Coal Mines (Part 1)

May. 30, 2020

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The geological conditions of coal fields are complex, and natural disasters such as gas, water damage, and high ground stress severely restrict coal mine safety production. Underground coal mine drilling construction is the most effective and direct means for comprehensive gas control, mine water hazard prevention, detection of hidden disaster-causing factors, and prevention of rockburst pressure. It is an important geological support technology for coal mine safe and efficient mining.

Due to the narrow space of coal mine tunnels and the explosion-proof requirements under special environmental conditions, conventional non-explosion-proof ground drilling equipment and instruments cannot be used directly downhole, and the requirements for underground transportation, ventilation, water supply, and electricity are also directly related to the use and site of drilling equipment The construction has a great impact. The construction of large-diameter holes, large-angle holes, and various types of holes with high depth and accuracy requirements under complex coal and rock formations is difficult to construct, and stricter requirements are imposed on drilling equipment [1]. Based on the above practical problems, domestic and foreign Relevant scientific research units and enterprises have carried out long-term research and equipment research and development in the field of underground coal mine drilling equipment, and have made great technological progress.

Crawler Mounted Drilling Rigs

Crawler Mounted Drilling Rigs

1 Current status of underground drilling equipment at home and abroad

At present, the drilling capacity of underground drilling equipment in coal mines has grown to more than 2 000 m and has evolved from a single split structure to multiple models such as crawler and directional drilling rigs. The specifications and varieties of drilling tools supporting drilling equipment are increasing. Product performance has steadily improved. With the increasing requirements for the accuracy of drilling trajectory control in coal mine geological anomaly detection, gas extraction and water damage prevention in Chinese coal mines, the drilling technology of the traditional rotary drilling rig supporting stable combination drilling tools has drilling direction control Difficulty, limited depth, low drilling utilization rate and other shortcomings lead to a large number of drilling works, there are blind spots in the drilling coverage, and long-distance advance drilling cannot be implemented, and the contradiction between excavation and replacement cannot be effectively resolved, and efficient comprehensive mining can In this way, the conventional rotary drilling rig is still the main drilling equipment for gas mining, water drainage and outburst prevention in most coal mines. With the continuous development of drilling technology, directional drilling technology, and equipment for near-horizontal measurement while drilling in coal mines is a new technology in the field of drilling engineering. Because of its high drilling efficiency, large drilling depth, and drilling trajectory can be measured and controlled The advantages of effective extension in coal seams, one-hole multi-branch, high single-hole drainage gas concentration, and a large area of drilling gas drainage area have become new methods for efficient drilling in underground coal mines. Widely promoted and applied, the drilling depth record, which represents the level of technical equipment, has also been continuously improved. After breaking through the kilometer drilling depth in 2008, the hole depth record has been continuously refreshed. The 2 311 m created at Shendong Baode Coal Mine in December 2017 Kong Shen record, was broken again at the beginning of 2019.

According to the characteristics of structure type, drilling process method, functional use, main characteristic performance parameters, and structure type, downhole drilling rigs usually have multiple classification methods, such as Crawler Mounted Drilling Rigs, directional drilling rig, soft coal drilling rig, exploration Some drilling and drilling rigs, high-power drilling rigs, and electronically controlled drilling rigs are scientifically standardized and compliant with standards, and some of them are relatively popular to cater to market users but also meet the needs of the site. In user selection and tender purchase, they are also because of the model The naming creates some problems that need to be managed and constrained by scientific and standardized standards and industry regulatory authorities for reasonable compliance.