振荡冲击器研究与应用

发布时间：2018-08-18 21:35

【摘要】：随着水平井、大位移井等复杂结构井在油气田勘探开发中建井比例越来越大,带来了机械钻速低、井眼轨迹不易控制、钻具托压、井眼不规则等一系列问题。振荡冲击器工具能够相应地解决上述问题,具有很大的发展前景。目前,只有国外少数公司掌握了振荡冲击器工具的关键技术,国内对振荡冲击器工具的各项研究尚处于起步阶段,本文分别从工具的结构设计、工作原理、工作特性、破岩机理、降摩减阻机理、工具试制及工具的地面及现场试验分析等方面对振荡冲击器进行了研究与应用,对该工具在国内的研究与应用具有重要意义。(1)设计了振荡冲击器工具结构,主要包括振动总成、动力总成和阀轴总成。设计的新型阀轴总成结构更优异,可选配低速螺杆,提高了工具寿命和可靠性,设计的双向振动总成无论在拉伸还是压缩状态下都能工作。确定了其通过控制过流面积周期性变化,将部分水力能量转化成工具轴向振动的机械能量,激发与振荡冲击器相串联的井下工具发生轴向振动,达到降摩减阻的目的工作原理；建立了振荡冲击器水击和纵向振动的数学物理模型,运用VB6.0编制了振荡冲击器工作特性计算软件,计算表明振荡冲击器的水击作用会对井底岩石产生一个附加的冲击动载荷,该动载荷的作用形式为正(余)弦曲线,动载荷的峰值与振荡冲击器的最大与最小过流面积的差值有关,动载荷的频率与振荡冲击器动力部分的转速和钻井液的排量有关；振荡冲击器在井底的工作状态为有阻尼的单自由度强迫振动,受水击简谐激励的系统稳态响应也是简谐的,其振动频率等于水击激励的频率,水击激励与振动响应之间有一相位差Ψ；在一个周期内水击激励输入的功与摩擦阻尼消耗的功相等。(2)通过对工具工作特性的研究,确立了工具以动静载荷组合破岩为主,“负压”脉冲射流破岩为辅的复合破岩方式。运用数值模拟方式对破岩过程进行研究,研究了不同岩石,不同工作频率、不同峰值载荷条件下工具的破岩效率,工具在16Hz时的破岩效率最高,破岩效率随着工具峰值冲击动载荷的增大而增大,当峰值动载荷达到10kN以上时,破岩效率趋于稳定；同时对该工具与常规旋转钻井和旋转冲击钻井破岩方式进行了详细对比分析,为今后振荡冲击器工具结构的优化,建立相应的钻井工艺提供了理论依据。(3)研究了振荡冲击器作用下的水平井钻井管柱摩阻变化规律,建立了振动摩擦力学模型,阐述了工具降摩减阻机理,分析了摩阻影响因素,并对振荡冲击器安放位置进行了研究。提出了振动摩擦过程中,有效摩擦系数降低是振动摩擦力小于最大静摩擦力的根本原因,将静摩擦转变为振动摩擦是振荡冲击器工具降摩减阻的基本原理；摩阻影响因素包括摩擦系数、钻井参数和钻具组合等,其中摩擦系数的影响相对较大；振荡冲击器安放位置的基本准则是其提供的振击力能够克服由振荡冲击器到钻头处的最大静摩擦阻力,且多个振荡冲击器工具安装位置的确定遵循从井底往上依次确定的原则。(4)校核了工具的抗拉强度和抗扭强度,完成了φ165mmm振荡冲击器工具的试制,并对钻具组合进行了推荐。直井中振荡冲击器应尽可能采取近钻头钻具组合,水平井中振荡冲击器可以位于MWD上面,也可以位于MWD下面；在同一钻柱组合中,在满足现场水力参数设计的情况下,可以串联多套振荡冲击器工具。(5)对试验样机进行了一次地面试验,三次现场试验,验证了工具的可靠性和功效。振荡冲击器的工作频率与螺杆转速成正比,工作压降约为3-4MPa,振幅9-12mm,水击力大于100kN@27L/s;点接触式TC轴承和碳化钨的阀片组有利于延长工具寿命。振荡冲击器工具本体强度满足现场工况要求。工具在井下正常工作时,对MWD信号无干扰,不会对井下相串联的其它井下工具造成损坏,其井下兼容性是友好的。振动短节碟簧的安装方式决定工具在受拉还是受压状态下工作,双向振动短节无论在受压还是受拉状态下都能工作；使用振荡冲击器的井段比没使用振荡冲击器的井段平均机械钻速提高38.4%。
[Abstract]:With the increasing proportion of complex structural wells such as horizontal wells and extended reach wells in the exploration and development of oil and gas fields, a series of problems have been brought about, such as low penetration rate, difficult control of borehole trajectory, underpinning pressure of drilling tools and irregular boreholes. A few companies have mastered the key technology of oscillatory impactor tools. The domestic research on oscillatory impactor tools is still in its infancy. In this paper, the oscillator impactors are studied from the aspects of tool structure design, working principle, working characteristics, rock breaking mechanism, friction reduction mechanism, tool trial-manufacture and tool ground and field test analysis. The research and application of the tool are of great significance to the research and application of the tool in China. (1) The tool structure of the oscillator impactor is designed, including the vibration assembly, the power assembly and the valve shaft assembly. By controlling the periodic change of the flow area, the hydraulic energy can be transformed into the mechanical energy of the axial vibration of the tool, and the axial vibration of the downhole tool in series with the oscillating impactor can be excited to achieve the purpose of reducing friction and drag. Mathematical and physical models of water hammer and longitudinal vibration of the oscillating impactor are developed by using VB6.0. The calculation shows that the water hammer of the oscillating impactor will produce an additional dynamic impact load on the bottom hole rock. The action form of the dynamic load is positive (cosine) curve, the peak value of the dynamic load and the maximum and the maximum of the oscillating impactor. The frequency of the dynamic load is related to the rotational speed of the dynamic part of the oscillating impactor and the displacement of drilling fluid; the working state of the oscillating impactor at the bottom of the well is a single degree of freedom forced vibration with damping, and the steady-state response of the system excited by the simple harmonic water hammer is also simple harmonic, and the vibration frequency is equal to the frequency of the water hammer excitation. There is a phase difference between water hammer excitation and vibration response_. The input work of water hammer excitation is equal to that of friction damping in a period. (2) By studying the working characteristics of the tool, the composite rock breaking mode with the combination of dynamic and static loads as the main method and with the assistance of negative pressure pulse jet is established. The rock-breaking process is studied in this paper. The rock-breaking efficiency of the tool under different rock, different working frequency and different peak load conditions is studied. The rock-breaking efficiency of the tool is the highest at 16Hz. The rock-breaking efficiency increases with the increase of the peak impact dynamic load of the tool. The tool is compared with conventional rotary drilling and rotary percussion drilling in detail, which provides theoretical basis for the optimization of tool structure and the establishment of corresponding drilling technology. (3) The variation law of frictional resistance of horizontal well drilling string under the action of oscillating percussion drilling is studied, and the vibration friction mechanics model is established. It is pointed out that the reduction of effective friction coefficient is the fundamental reason why the vibration friction force is less than the maximum static friction force in the process of vibration friction, and that the change of static friction into vibration friction is the key to reduce friction and friction of the oscillating impactor. Friction factors include friction coefficient, drilling parameters and drilling tool assembly, among which friction coefficient is relatively large; the basic criterion for placement of oscillatory impactors is that the vibration force provided by them can overcome the maximum static friction resistance from the oscillatory impactor to the bit, and multiple oscillatory impactor tools are installed. (4) The tensile strength and torsional strength of the tool are checked, and the trial production of the tool is completed, and the drilling tool assembly is recommended. In vertical wells, the oscillatory impactor should be as close to the bit as possible, and in horizontal wells, the oscillatory impactor can be located on MWD. In the same drill string combination, several sets of oscillatory impactor tools can be connected in series under the condition of satisfying the design of field hydraulic parameters. (5) A ground test and three field tests have been carried out to verify the reliability and effectiveness of the tool. The operating frequency of the oscillatory impactor is proportional to the screw speed. The working pressure drop is about 3-4 MPa, the amplitude is 9-12 mm, and the water hammer force is greater than 100 kN@27L/s. The point contact TC bearing and the tungsten carbide valve plate group are beneficial to prolong the tool life. The strength of the oscillator impactor tool body meets the requirements of the field working conditions. The tool has no interference to the MWD signal and will not cause any other downhole tools connected in series. The installation mode of the vibrating short section disc spring determines that the tool works under tension or compression, and the two-way vibrating short section can work under both compression and tension. The average penetration rate of the section using the vibrating impactor is 38.4% higher than that of the section without the vibrating impactor.
【学位授予单位】：西南石油大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TE927

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