Drainage of old goaf water by Long-distance directional drilling and water quantity calculation method
Chen Zixin1, Zhao Baofeng2, 3, Zhao Junjie1
1. Jinfeng Coal Mine of Ningxia Coal Industry Co., Ltd., National Energy Group, Yinchuan 750011, China; 2. Xi 'an Research Institute ( Group ) Co., Ltd., Xi 'an 710054, China; 3. Shaanxi Provincial Key Laboratory of Coal Mine Water Disaster Prevention and Control Technology, Xi 'an 710177, China
Long-distance directional drilling to drain old goaf water had the advantages of controllable drilling trajectory and high drainage efficiency. In order to calculate the water volume of the old goaf water before the drainage of the old goaf water, the Bernoulli principle in hydraulics was used, and the head loss of the old goaf water from the end hole position of the borehole to the opening position was considered. The calculation formula of the water volume of the old goaf water drilling was given, and the calculation formula of the water level of the old goaf was obtained. By comparing with the amount of water in the underground goaf water drainage borehole, the amount of water obtained by the formula for calculating the amount of water in the borehole was consistent with the actual situation, which could be used as a calculation method for the amount of water in the old goaf water drainage borehole. It used the amount of drilling water to calculate the water level in the old goaf, which could save the observation holes of the ground or underground water level in the old goaf, and reduce the engineering quantity and capital investment of the prevention and control of the water disaster in the old goaf.
