Recently, it is reported from Huainan Geological Exploration Engineering Branch that the company has successfully constructed a large-diameter directional drilling borehole with a diameter of 200mm in Zhangji Coal Mine by using ZDY23000LDK high-power automatic directional drilling rig of CCTEG Xi'an Research Institute (Group) Co., Ltd.
Drilling accidents such as borehole collapse, block falling, shrinkage and oversize are common in Huainan coal field due to poor stratum stability and complex geological conditions. In addition, the underground construction is troubled by a series of problems such as high working environment temperature and high labor intensity due to large mining depth. ZDY23000LDK high-power automatic directional drilling rig developed by CCTEG Xi'an Research Institute adopts a crawler layout structure and is used in complete sets with crawler mud pump trucks. It has the advantages of independent walking ability, convenient relocation, flexible site layout and strong gradeability, and is suitable for large-diameter near-horizontal deep borehole directional drilling construction.
In order to ensure the smooth progress of on-site construction, Xi'an Research Institute selected backbone personnel to form a party member vanguard team, which fully cooperated and closely collaborated with Huainan Geological Exploration Engineering Branch Downhole Special Drilling Work Area, carefully formulated the method statement, established an overall coordination mechanism, and determined the objectives and tasks and defined the time limit for responsibility in the management mode of "tasks posted on the wall, wall chart operations and quantitative promotion". During the construction process, two rounds of on-site seminars were held for drilling rig equipment, supporting machines and tools and construction technology to formulate technical schemes for drilling rig optimization and drilling technology classification based on the site needs of Huainan Mining Area.
Up to now, 1#, 2# and 3# large diameter boreholes have been completed. During the construction process, difficulties such as large rock hardness and difficult drill cutting discharge were overcome. Finally, three boreholes were completed with final depths of 568m, 639m and 560m respectively, creating one-time drilling depth record of large diameter (200mm) borehole in China.
"This breakthrough not only deepens the gas drainage technology of 'replacing roadways with holes', but also greatly saves drilling quantities, reduces drilling maintenance costs, reduces personnel cost investment, improves drilling utilization rate and gas drainage efficiency, which plays a positive role in ensuring safe, efficient and green mining of coal mines. It is really worth it!" Huainan Geological Exploration Engineering Branch downhole special drilling work area deputy mayor Qi Jun said.
It is an innovative application of gas pre-drainage and outburst elimination in large diameter directional constructed by high power automatic directional drilling rig. The success of this application is of great significance to effectively promote the transformation of production mode of coal enterprises, enhance their disaster control ability and reduce costs.
