【作者】 黄海；

【导师】 吴泽兵；

【作者基本信息】 西安石油大学 ， 机械工程（专业学位）， 2021， 硕士

【摘要】 目前,大位移井、水平井已成为石油天然气勘探开发过程采用的主要井型。但是,水平井因其井斜方位动态变化、水平段位移较长、摩阻扭矩大以及井眼轨迹难以控制等特征严重制约了水平井的延伸钻进能力。明确钻柱在钻进过程的动态工作行为,探索降低钻柱摩阻扭矩的方法已成为避免钻柱过早失效、评价钻柱动态工作安全性和提高水平井开发程度的关键。本文采用仿真与实验结合的办法,开展了钻柱动态特性、摩阻扭矩变化规律的研究。主要内容有:(1)基于有限单元法研究并建立了水平井全井钻柱动力学方程,探讨了钻柱与井壁的接触状态,确定了动力学方程求解边界条件。(2)基于ADAMS软件建立了水平井全井井筒、钻柱系统的仿真模型,验证了模型的可靠性及正确性。(3)研究了钻柱系统的横向振动、扭转振动、井眼内的运动轨迹、运动状态及其与井壁的接触状态和沿程摩阻,结果表明:弯曲段下部、水平段前部钻柱横向振动强度较高;钻头处扭转振动最明显;钻柱整体趋势偏向下井壁,在随机运动过程伴随翻滚运动状态;弯曲段钻柱与井壁的接触状态复杂,水平段接触平稳;旋转钻进能较滑动钻进降15%左右的沿程摩阻。(4)研究对比了仿真模拟与真实试验条件下钻压、转速对钻柱接触的影响规律,分析了钻压、侧向力对钻柱失稳变形的影响规律,研究了水平井全井钻柱旋转钻进的摩阻、扭矩变化规律。结果表明:仿真模型具有一定的准确度;钻压加剧了钻柱失稳变形,侧向力改变钻柱失稳变形后的弯曲方向;井口扭矩及大钩载荷呈波动趋势。更多还原

【Abstract】 At present,large displacement wells and horizontal wells have become the main types of oil and gas exploration and development process.However,the extended drilling ability of horizontal wells is seriously restricted due to the dynamic changes of well inclination,long horizontal displacement,large friction torque and difficult control of wellbore trajectory.Clearing the dynamic working behavior of the drill string in the drilling process and exploring the method to reduce the friction torque of the drill string have become the key to avoid premature failure of the drill string,evaluating the dynamic working safety of the drill string and improving the development level of horizontal wells.In this paper,the dynamic characteristics of drill string and the change rule of friction torque are studied by combining simulation and experiment.The main contents are :(1)Based on the finite element method,the dynamic equation of drilling string in horizontal well is studied and established,the contact state between drilling string and wellbore is discussed,and the boundary conditions for solving the dynamic equation are determined.(2)Based on ADAMS software,the simulation model of the whole wellbore and drill string system of horizontal wells is established,and the reliability and correctness of the model are verified.(3)The lateral vibration,torsional vibration,trajectory,motion state,contact state with wellbore and friction along the wellbore of the drill string system are studied.The results show that the lateral vibration intensity of the drill string in the lower part of the bending section and the front part of the horizontal section is high.The torsional vibration at the bit is most obvious;The overall trend of drill string is inclined to the lower wall,showing a rolling motion state in the random motion process;The contact state between drill string and borehole wall in bending section is complex,and the horizontal section is relatively stable;Rotary drilling can reduce friction by about 15 % compared with sliding drilling.(4)The influence of drilling pressure and rotational speed on the contact of drill string under simulation and real test conditions is studied and compared.The influence of drilling pressure and lateral force on the instability and deformation of drill string is analyzed.The friction and torque variation of rotary drilling of horizontal well drill string are studied.The results show that the simulation model has certain accuracy;Drilling pressure intensifies the instability deformation of drill string,and lateral force changes the bending direction of drill string after instability deformation.The wellhead torque and hook load showed a fluctuating trend.更多还原