1. Introduction
In September 2018, water inrush occurred in 11202 working face of Yuyang Zhongneng Yuan Datan Mining Co., Ltd. According to the record of mine construction, the maximum water inrush volume from coal roadway reached 360 m3/h. The static water storage in coal seam is the main geological factor that restricts the rapid roadway heading in this mine.
2. Mine water hazard treatment solution
According to the request of Yuandatan Mining Co. , Ltd. , one drilling field is arranged at the heading faces of 11202(1270m) and Yunshun (1050m) , and the directional drilling track is drilled along the coal bed. The target coal seam is relatively thin (1.1-1.5 m) and coal seam undulation is obvious. This brings certain difficulty to the water drainage drilling construction. It is very important to control the directional drilling trajectory according to the change of formation lithology.
3. Construction situation
The project has 2 boreholes with total footage of 800m. Construction start from the drill site to the direction of roadway excavation. The plane control point distance between two boreholes is more than 400 m and the profile control horizon is less than 1.5m. The project actually completed one directional borehole in 11202 working face. The main borehole depth is 819m. Several sidetracks were constructed at the same time, which ensured that the borehole trajectory was 100% inside the target layer.
4. Achieved accomplishment
Through the implementation of this project, the static water storage in the coal seam of the 11202 working face was detected. Maximum water output was 20m3/h, the water output was stable at 13m3/h after continuous observation every 1 hour for 10 hours. After drainage for a certain period of time, the final water output declined to 2~3 m3/h. Combined with the geophysical exploration results in the low resistivity abnormal area of 11202 working face, most of the drilling holes are located in the area without low resistivity abnormal.
5. FAQ
Q 1: What are the design principles of water exploration and drainage boreholes in this coal seam?
A: According to the geological data and the concrete underground construction conditions, it is reasonable to select the type of equipment, the construction site and the arrangement of boreholes, and it is reasonable to arrange the trajectory of drilling holes according to the contour line of the coal floor, the lithology of the roof and the floor and the influence range of water drainage. According to the characteristics of seam coal and rock in the project area, the directional long borehole can be accurately located to ensure the borehole trajectory to be constructed according to the design and to extend the borehole depth in the coal seam as far as possible.
Q 2: Can a main borehole be constructed when directional drilling along a thin seam?
A: In directional drilling, it is very difficult to construct a main borehole because the coal seam is thin. The stratum itself has certain fluctuation and change tendency, even fold and other geological structure appear in some areas. In order to keep the borehole extending in the target bed to meet the design requirement, it is inevitable that some boreholes may touch the roof or the floor interface. When the drilling operation cannot be continued due to the great change of structure or stratum, it is necessary to retreat to a certain location and start a sidetrack. This may increase drilling footage.
Hot Tags: water drainage borehole drilling, China, manufacturers, suppliers, factory, wholesale, price list, buy, for sale,
