扭转冲击PDC钻头的破岩机理及实验研究

发布时间：2018-01-13 08:05

本文关键词：扭转冲击PDC钻头的破岩机理及实验研究　出处：《东北石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着所钻的深井和超深井数量的不断增加,钻进中所遇到的情况更复杂,破岩难度大,这使得钻井过程中普遍存在周期长、钻速慢、成本高等问题,破岩技术是油气钻井技术的核心内容,破岩效率的高低对油田勘探开发速度和成本起着决定性作用,如何通过科学手段来完善高效破岩技术,变得势在必行。PDC钻头具有破岩效率高、钻速快、寿命长、性能稳定等优点,在世界范围内被广泛应用于现场钻井中,但到目前为止,有些理论研究仍未与现场实践进行很好的结合。为了进一步扩大PDC钻头应用范围,实现钻头的更加科学设计,论文开展了扭转冲击作用下PDC钻头破岩机理的研究工作。本论文采用理论分析以及室内实验的方法,进行了扭转冲击PDC钻头破岩机理的研究工作。具体内容如下:1.建立了简化钻井系统模型,对PDC切削齿侵入岩石过程进行分析,得到了钻头钻进过程中的边界条件与控制条件,对扭转冲击PDC钻头的运动状态进行了解释。2.建立了围压作用下切削片状模型,对切削齿尖端进行受力分析,考虑多种参数的作用,得到了围压作用下切向力及轴向力公式,同时将金属切割学的知识考虑进模型中,提出了一个新的理论—碎屑球带形态理论,将碎屑球带形态与井底间的摩擦作用及带状切屑与碎屑球之间相对运动时的摩擦力考虑进模型中,得到新的切向力及轴向力公式。3.从单齿切削二维简图入手,同时将剪切面在岩石上的投影假设为椭圆形,建立了单齿的岩石切削体积模型,得到了PDC齿切削体积的公式,同时对PDC单齿切削效率进行了重新定义。4.利用扭转冲击破岩系统,针对不同岩性岩石,模拟扭转冲击条件下PDC钻头钻进实验,对实验数据进行分析,探寻了单因素对于钻头钻速的影响,同时对模型中涉及到的切削齿尺寸、后倾角对破岩效率的影响规律进行了验证,最后,给出了钻头选用的一些基本原则。
[Abstract]:With the continuous increase of the number of deep wells and ultra-deep wells, the situation encountered in drilling is more complex and difficult to break rock, which makes the drilling process generally exist problems such as long cycle, slow drilling speed, high cost and so on. Rock breaking technology is the core content of oil and gas drilling technology. Rock breaking efficiency plays a decisive role in exploration and development speed and cost of oil field. PDC bit has the advantages of high rock breaking efficiency, fast drilling speed, long life, stable performance and so on. It has been widely used in field drilling in the world, but up to now. Some theoretical studies have not been well combined with field practice. In order to further expand the scope of application of PDC bit and realize more scientific design of bit. In this paper, the rock breaking mechanism of PDC bit under torsional impact is studied. The method of theoretical analysis and laboratory experiment is used in this paper. The rock breaking mechanism of torsional impact PDC bit is studied. The concrete contents are as follows: 1. A simplified drilling system model is established and the process of PDC cutting teeth invading into rock is analyzed. The boundary conditions and control conditions during bit drilling are obtained, and the motion state of torsional impact PDC bit is explained. 2. The cutting flake model under confining pressure is established. The forces on the tip of the cutting teeth are analyzed and the formulas of tangential force and axial force under confining pressure are obtained considering the effects of various parameters. At the same time, the knowledge of metal cutting is taken into account in the model. In this paper, a new theory, the theory of clastic ball-shape, is proposed, in which the friction between the ball-shape and the bottom hole and the friction force between the band-shaped chip and the clastic sphere is taken into account in the model. A new formula of tangential force and axial force is obtained. Starting with the two-dimensional schematic diagram of single tooth cutting, and assuming that the projection of shear plane on rock is elliptical, a single tooth rock cutting volume model is established. The formula of cutting volume of PDC teeth is obtained, and the cutting efficiency of PDC single tooth is redefined .4.Using torsional impact rock breaking system, aiming at different lithologic rocks. The experiment of PDC bit drilling under torsional impact condition is simulated. The experimental data are analyzed and the influence of single factor on bit drilling speed is explored. At the same time, the cutting tooth size involved in the model is also discussed. The effect of the inclination angle on the rock breaking efficiency is verified. Finally, some basic principles of bit selection are given.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE921.1

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