煤层分支孔水力钻进超短半径转向机理研究

发布时间：2018-11-14 09:59

【摘要】：煤层瓦斯的有效抽采，对安全、高效的煤矿开采具有重要意义。利用径向水平井技术，在原有煤层巷道卸压主孔内，钻出多个水平分支孔，对于提高瓦斯抽采效果具有促进作用。根据煤层卸压主孔空间狭小、工况恶劣的特点，对煤层垂直分支孔钻进总成进行了概念设计，确定钻进总成由工具壳体、导向单元、送进单元三部分组成。钻管是辅助钻头完成90°转向，钻出分支孔的关键部件。为确定钻管参数，进行了室内钻管选优实验，测定了四种不同外径、壁厚、材料的钻管通过导向轨道的转向阻力，研究了各钻管参数对转向阻力的影响规律。实验表明：无内压条件下，其他参数相同时，钻管外径越小转向阻力越小；壁厚越小转向阻力越小；塑性强度越小转向阻力越小。据此选定了不锈钢作为钻管材料，并利用理论计算结合实验的方法进行了抗内压校核。利用理论计算，分析了导向单元转向阻力的影响因素，，发现转向半径及较直偏量对转向阻力影响较大，据此初步设计了导向轨迹。为了减小转向阻力，对钻管转向过程进行了数值模拟，观测了钻管的应力分布，分析了转向阻力随送进距离的变化规律。模拟发现，转向阻力在导向轨迹曲率改变处增大，且与曲率改变量呈正相关。据此优化了导向轨迹，数值模拟表明，优化后转向阻力降低了13.7%。针对送进单元中钻管屈曲的现象，进行了非线性屈曲模拟，发现钻管在扶正筒内呈正弦屈曲，由于塑性屈服而失效。同时分析了钻管长度、扶正筒内径对最大轴向力的影响规律，发现其他参数相同时，钻管长度越大，最大轴向力越大；扶正筒内径越大，最大轴向力越小。最后，结合转向阻力设计了导向单元几何参数。
[Abstract]:The effective drainage of coal seam gas is of great significance to the safe and efficient mining of coal mines. By using radial horizontal well technology, several horizontal branch holes are drilled out in the main pressure relief hole of the original coal seam roadway, which can improve the gas drainage effect. According to the characteristics of the coal seam pressure relief main hole space is narrow and the working condition is bad, the concept design of the vertical branch hole drilling assembly of coal seam is carried out, and it is determined that the drilling assembly is composed of tool shell, guide unit and feed unit. The drill pipe is the key component to assist the drill to complete 90 掳steering and drill out the branch hole. In order to determine the parameters of drilling pipe, an indoor drilling pipe selection experiment was carried out, and the steering resistance of four kinds of drilling pipes with different external diameters, wall thickness and material through the guide track was measured, and the influence of the drilling pipe parameters on the steering resistance was studied. The experimental results show that the smaller the diameter of the drill pipe the smaller the steering resistance the smaller the wall thickness the smaller the steering resistance and the smaller the plastic strength when the other parameters are the same without internal pressure. Stainless steel was selected as drilling pipe material, and the internal pressure resistance was checked by theoretical calculation combined with experimental method. Based on the theoretical calculation, the factors affecting steering resistance of steering unit are analyzed. It is found that the steering radius and direct deviation have great influence on steering resistance. Based on this, the steering trajectory is preliminarily designed. In order to reduce steering resistance, the steering process of drill pipe was simulated, the stress distribution of drill pipe was observed, and the variation law of steering resistance with feeding distance was analyzed. It is found that the steering resistance increases at the curvature change of the steering trajectory and is positively correlated with the curvature change. Based on this, the steering trajectory is optimized and the numerical simulation shows that the steering resistance is reduced by 13.7% after optimization. The nonlinear buckling simulation of drill pipe in the feed element is carried out. It is found that the drill pipe is sinusoidal buckling in the centralizing tube and fails due to plastic yield. At the same time, the influence of the length of drilling pipe and the inner diameter of the centralizer on the maximum axial force is analyzed. It is found that the greater the length of drilling pipe, the greater the maximum axial force and the smaller the maximum axial force when other parameters are the same. Finally, the geometric parameters of the steering unit are designed according to the steering resistance.
【学位授予单位】：中国石油大学（华东）
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TD712.63

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