张集煤矿灰岩顺层定向钻进托压效应及影响因素分析

Back Pressure Effect of Limestone Consequent Landslide Directional Drilling and Analysis of Influencing Factors in Zhangji Coal Mine

针对张集煤矿坚硬灰岩顺层定向钻进中发现的钻孔孔深与孔口给进压力之间的变化规律,在400~500 m孔深时出现托压现象,运用钻柱弹性送钻理论对托压效应产生的机理进行了分析,能够很好地解释张集煤矿坚硬灰岩顺层定向钻进中发现的规律,托压效应的产生主要是受到了钻孔摩阻的影响。在此基础上,对托压效应的影响因素进行了分析,主要影响因素有:地层岩性、曲率和位移、垂深与岩屑、孔深、自重与给进压力,并从减小坚硬岩层滑动定向钻进托压效应影响的角度出发,从减小钻柱与孔壁的摩阻、研发减阻降摩工具和复合钻进方面给出了优化建议。

According to variation laws between borehole depth and orifice feed pressure found in consequent landslide directional drilling of hard limestone in Zhangji Coal Mine,back pressure phenomenon appeared at 400 m to 500 m hole depth.Theory of the drill string elastic feeding theory was used to analyze the mechanism of back pressure effect,which explained the law found in the consequent landslide directional drilling of the hard limestone in Zhangji Coal Mine.The main effect of the generating back pressure effect was due to the influence of drilling friction.On this basis,the influencing factors of the back pressure effect were analyzed.The main influencing factors were:formation lithology,curvature and displacement,vertical depth and cuttings,hole depth,self-weight and feeding pressure.And from the perspective of reducing the influence of slide directional drilling on the hard rock layer,the optimization suggestions were given in reducing the friction of the drill string and the hole wall,developing the anti-friction and drag reduction tool,compound drilling.