Study On Directional Drilling Technology Of AD-4 Exploratory Drainage Hole In Longwanggou Coal Mine

Coal mine water disaster has always been one of the major mine disasters restricting coal mine safety production.AD-4 exploration and drainage hole is a directional drilling hole affecting the control of water disasters in Longwanggou Coal Mine.Based on the demonstration project of Xi ’an Research Institute Co.,Ltd.of China Coal Industry Group in Longwanggou Coal Mine of Ordos City,Inner Mongolia Autonomous Region,starting from the demand of water disaster prevention and control in Longwanggou Coal Mine,this paper uses analytic hierarchy process,MATLAB simulation calculation method,Flac 3D numerical simulation and grey correlation method to study,and draws the following conclusions:This paper relies on the demonstration project of Xi ’ an Research Institute Co.,Ltd.(hereinafter referred to as ’ Xi’ an Research Institute ’)in Longwanggou Coal Mine,Ordos City,Inner Mongolia Autonomous Region.Starting from the demand of water disaster prevention and control in Longwanggou Coal Mine,based on analytic hierarchy process,the weight of influencing factors of directional long borehole trajectory deviation in the study area is sorted,and the main control factors are analyzed.The drilling trajectory is optimized by MATLAB simulation and other methods.The Flac 3 D numerical simulation is used to study the stress distribution,displacement vector and displacement cloud map of the formation during drilling.Based on the analysis of the mechanism of drilling trajectory deviation,the scheme of piecewise trajectory control is formulated,which provides the basis for accurate control of drilling trajectory.The grey correlation method is used to systematically analyze various factors affecting the drilling efficiency,and the reasonable rock breaking tools and supporting drilling equipment are optimized.The following conclusions are drawn from the above research:(1)Using the analytic hierarchy process(AHP)and the yaahp software,it is calculated that the weights of the soft and hard interbeds,the weight of the drilling tool and the anisotropy of the rock occupy the first three,which are 0.31,0.22 and 0.20,respectively.Based on the analysis results,these three factors are emphatically analyzed,which provides the basis for the accurate control and design of the next drilling trajectory.(2)The optimization toolbox in MATLAB software is used to optimize the drilling trajectory of AD-4.It is obtained that the vertical depth of the oblique point V1 is 53 m,the increase angle is 26.65°,the increase slope is 7.84°/30 m,and the shortest hole depth is m.The plane trajectory construction map and the profile trajectory construction map are drawn to further optimize the drilling traj ectory design.(3)The results of Flac 3D numerical simulation show that in the drilling process,due to the existence of sandstone mudstone interlayer increases the difficulty of drilling trajectory control,and the drilling trajectory often deviates.In the actual drilling process,by reasonably adjusting the drilling scheme,the actual drilling trajectory is basically consistent with the design trajectory,and the expected effect is achieved,which fully verifies the reliability of the numerical simulation.The research results also have reference significance for other similar mining areas.(4)The grey correlation method is used to systematically analyze the various factors affecting the drilling efficiency,and it is concluded that the maximum correlation values of pump volume,drilling pressure and rotational speed are 0.81,0.81 and 0.71,respectively,which are the main factors affecting the drilling speed.The new ZDY12000LD drilling rig+BLY390 pump truck+matching downhole power drilling tool combination and four-wing flat-bottom PDC bit developed by Xi’an have achieved the comprehensive drilling efficiency of 5.31 m/h after field application.The purpose of efficient drilling is achieved in terms of drilling efficiency,drilling stability and drilling trajectory control.