Construction technology and development tendency of high level borehole for gas drainage in goaf
Sun Rongjun
Li Quanxin
Fang Jun
Xu Chao
Abstract：In order to solve the high construction cost,low efficiency and other problems existed in the gas drainage from the goaf of the coal mining face with the special gateway and pipeline buried method,based on the gas drainage technical principle of the goaf and top corner with the high level borehole in the roof,a coal and gas simultaneous mining system established with the pre-drainage borehole and high level borehole was provided.The advantages and disadvantages of the high level borehole constructed with the available rotary drilling technology and the sliding direction drilling technology were analyzed.The paper introduced the new developed method and experiment application of the complex direction and large diameter rotary reaming drilling technology.The completed depth of the high level direction drilling could reach to 1 026 m and the reaming diameter could reach to 153 mm.Meanwhile,according to the small diameter of the once completed borehole,slow speed of secondary rotary reaming,gas drainage channel jammed by the open completed borehole and other problems existed in the present high level direction drilling borehole,the development tendency of the large diameter once completed borehole technology,complex reaming drilling technology and screen pipe completed technology were provided,so as to further improve the once completed diameter,drilling efficiency,drilling depth and borehole utilization time of the high level directional drilling,to reduce the construction risk and to improve the borehole economics as well as the gas drainage effect.
Keywords：gas drainage of goafhigh level boreholecomplex directional drillinglarge diameter once completed drillingcomplex reamingborehole completed technology of screen pipe
Publication Date：2017-01-01
Pages：7( 94-99,213 )