PDC钻头复合冲击破岩机理及模型研究

发布时间：2018-05-23 21:57

本文选题：PDC钻头 + 粘滑振动　；参考：《东北石油大学》2017年硕士论文

【摘要】：随着社会经济的发展,对石油资源的需求越来越多,勘探开发也渐渐由浅井到深井,甚至超深井,在这些区域,地层岩石的特点是,硬度大,研磨性强,可钻性差,这阻碍了深部硬地层机械钻速的提高。因此针对在硬地层钻进过程中出现的钻头失效快、机械钻速低、钻井成本高等问题,需要研制开发出一种新型的破岩工具来提高机械钻速。针对上述现象,国内外的相关研究机构大力开展了钻井技术研究,虽然传统的轴向和扭转冲击钻井技术都能够提高机械钻速,但各自仍存在缺点。轴向冲击的冲击功相对较小,因为当冲击频率超过某一数值时,会对冲击器的寿命造成影响,因此提高机械钻速的幅度并不大;扭转冲击钻井在破岩效率方面比较高,但在钻遇高研磨性地层的时候,要求钻头与冲击器之间的匹配程度要高。因此可以充分结合它们的优点,形成一种新的钻井技术——复合冲击钻井技术,它可以抑制甚至消除钻头在钻井过程中出现的粘滑振动,减少跳钻现象的发生,从而提高复杂地层的机械钻速。本文基于波动理论,建立了PDC钻头钻进过程中的钻柱动力学模型,分析了跳钻现象和粘滑振动现象产生的原因;建立了PDC钻头的复合冲击模型,详细地分析了复合冲击的作用;通过现场试验,分析了复合冲击工具的破岩效果。本文取得了以下的研究结论:(1)基于波动理论,建立了PDC钻头钻进过程中钻柱的动力学模型,同时给出了模型的边界条件,对模型进行求解,得到了描述钻井行为的模型;(2)分析了跳钻现象和粘滑振动,得出了PDC钻头粘滑振动现象的非线性方程,得到了钻头干摩擦系数的计算公式,根据公式做出了钻头的摩擦扭矩随角速度的变化曲线,该曲线可以很好的模拟低角速度下的库伦摩擦特性,同时指出,钻头和岩石间的非线性摩擦扭矩产生的抗阻尼特性是粘滑自激振动产生的原因;(3)建立了PDC钻头的复合冲击模型,分析了常规钻进与复合冲击钻进时钻头角速度、钻头扭矩以及钻头轴向位移随时间的变化情况,结果表明复合冲击作用可以抑制PDC钻头的粘滑振动,减少跳钻现象的发生;(4)基于复合冲击破岩理论,研制了钻井工具并在金跃204井和齐古1井进行了现场试验,与邻井的破岩效果对比得出:复合冲击工具能够有效的保护PDC钻头,减少扭矩波动,从而抑制钻头的粘滑振动,降低钻头的磨损程度,提高单只钻头进尺,提高机械钻速。本文的研究能够抑制钻头的粘滑振动,大幅度提高机械钻速,具有推广价值,应用前景广阔。
[Abstract]:With the development of society and economy, the demand for petroleum resources is increasing, and the exploration and development are gradually from shallow wells to deep wells, even ultra-deep wells. In these areas, the formation rocks are characterized by high hardness, strong abrasiveness and poor drillability. This hinders the improvement of mechanical drilling speed in deep hard formations. So it is necessary to develop a new kind of rock breaking tool to improve the drilling speed in order to solve the problems such as fast bit failure low drilling speed and high drilling cost during hard formation drilling. In view of the above phenomenon, domestic and foreign related research institutions have vigorously carried out drilling technology research, although the traditional axial and torsional impact drilling technology can improve the mechanical drilling speed, but there are still shortcomings. The impact work of axial impact is relatively small, because when the impact frequency exceeds a certain value, it will affect the life of the percusser, so the increase of mechanical drilling speed is not large, and the torsional impact drilling is relatively high in rock breaking efficiency. However, when drilling in high abrasive formation, the matching degree between drill bit and percussion device is required to be high. Therefore, a new drilling technology, compound impact drilling technology, can be formed by fully combining their advantages. It can suppress or even eliminate the stick-slip vibration of drill bit during drilling, and reduce the occurrence of drilling jump. In order to improve the mechanical drilling speed of complex formation. Based on the wave theory, the dynamic model of drill string in the drilling process of PDC bit is established, and the causes of the phenomenon of jump and stick-slip vibration are analyzed, the compound impact model of PDC bit is established, and the function of compound impact is analyzed in detail. Through field test, the rock breaking effect of compound impact tool is analyzed. In this paper, the following conclusions are obtained: (1) based on the wave theory, the dynamic model of drill string in the drilling process of PDC bit is established, and the boundary conditions of the model are given, and the model is solved. In this paper, a model describing drilling behavior is obtained. The phenomenon of drilling jump and the vibration of stick-slip are analyzed. The nonlinear equation of stick-slip vibration of PDC bit is obtained, and the calculation formula of dry friction coefficient of bit is obtained. According to the formula, the variation curve of friction torque with angular velocity is obtained. The curve can well simulate the Coulomb friction characteristics at low angular velocity. At the same time, it is pointed out that, The anti-damping property of nonlinear friction torque between bit and rock is the reason of self-excited vibration of stick-slip. The compound impact model of PDC bit is established, and the angular velocity of bit during conventional drilling and composite percussion drilling is analyzed. The variation of bit torque and bit axial displacement with time shows that compound impact can restrain the stick-slip vibration of PDC bit and reduce the occurrence of drilling jump. The drilling tool has been developed and tested in Jinyue 204 well and Qigu 1 well. Compared with the rock breaking effect of adjacent wells, the compound impact tool can effectively protect PDC bit, reduce torque fluctuation, and thus restrain the stick-slip vibration of bit. Reduce the wear degree of bit, improve the advance of single bit, and improve the speed of mechanical drilling. The research in this paper can restrain the sticking-slip vibration of the bit and increase the drilling speed greatly. It is worth popularizing and has a broad application prospect.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE921.1

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