涡轮取心钻进钻具径向振动特征研究

Turbodrill is a kind of high efficiency bottom-hole drilling motor, which has a good application prospect. However, the radial vibration of core drilling process with turbodrill causes the drilling tool to be damaged easily and the core quality is poor. At present, the research on the vibration problem of core drilling with turbodrill is still blank. This project will study the vibration characteristics of the bottom-hole assembly(BHA) based on the actual working conditions of core drilling with turbodrill for the first time. Through theoretical analysis, the drill string will be divided into two parts: the upper low speed rotary drill pipe and the lower high speed rotary drilling tool, and the calculation model of the vibration of bottom-hole assembly will be established. The vibration characteristics of the BHA will be simulated with numerical simulation method, which will reveal the influence mechanism of the turbodrill on the vibration of the BHA. The vibration characteristics of the BHA will be tested and analyzed by drilling experiment, which will be used to modifiy and validate the results of theoretical analysis and numerical simulation results. The results of project will reveal the vibration mechanism and regularity of core drilling process with turbodrill, provide scientific and effective guidance for the design of the turbodrill, drilling parameters and BHA optimization, which will effectively improve the life of drilling tools and drilling efficiency, ensure core quality. It is not only important scientific significance but also has good engineering application prospect for deep resource exploration and development.

涡轮钻具是一种高效的孔底动力钻具，具有良好的应用前景，但是涡轮取心钻进过程中底部钻具径向振动导致钻具损毁严重、岩心质量差。目前针对涡轮取心钻进钻具振动问题的研究尚属空白。本项目首次针对高速涡轮钻具复合取心钻进实际工况开展底部钻具振动特性研究。通过理论分析，将钻柱分为上部低速旋转钻杆和下部高速旋转钻具两级，建立底部钻具振动计算模型；采用数值模拟的方法对底部钻具振动特性进行模拟研究，揭示涡轮钻具对底部钻具振动的影响机理；通过实钻实验对底部钻具振动特性进行测试分析，对理论分析和数值模拟结果进行修正和验证。该研究揭示了涡轮复合取心钻进底部钻具振动机理及规律，为涡轮钻具设计、钻进参数优化、钻具组合优选提供科学有效的指导，有效提高钻具寿命和钻进效率、保证岩心质量，对深部资源勘探开发不仅具有重要科学意义也具有很好的工程应用前景。

涡轮钻具具有高转速、低扭矩的特点，在取心钻进过程中取得了较好的应用效果。但受其高转速的影响，在取心钻进过程中横向振动十分明显，导致获取的岩心质量不佳，且对钻具寿命和井下安全有十分不利的影响。本课题针对涡轮钻具横线振动开展了研究与分析，基于涡轮取心钻进工况建立了涡轮复合取心钻进上部低速旋转和下部高速旋转两级钻具振动模型，并对钻具离井底和钻压作用下钻具振动机理进行了分析；通过数值模拟方法对不同取心钻具长度条件下钻具振动特征以及不同钻压、转速条件下钻具径向振动特征进行了模拟分析，并对其影响规律进行了分析；应用振动测量短节对钻具振动情况开展了室内测试，对理论分析和数值模拟结果进行了验证。研究表明钻具的横向振动随涡轮钻具工作转速的升高而升高，当钻压低于临界钻压时随钻压增大而降低，因此在钻进过程中应合理控制给定钻压，通过加压的方式可降低钻具工作转速，降低钻具的横向振动。在取心作业前，应根据取心任务要求尽可能选择长度较短的取心工具，可有效降低钻具横向振动。在项目研究的基础上，从涡轮叶片、推力轴承、稳定器等方面对涡轮钻具的结构进行了优化和改进。结合工程实践对项目研究成果进行了应用验证，取心钻进获取岩心的质量有明显的改善和提高。