【作者】 贾朋；

【导师】 苏义脑； 房军；

【作者基本信息】 中国石油大学 ， 机械设计及理论， 2010， 博士

【摘要】 本文以提高随钻测量钻井液连续波信息传输系统的传输速率为目的,围绕连续波发生器的设计和信号传输特性展开了若干关键问题的研究。在连续波发生器转阀阀口形状设计与优化、连续波发生器负载特性分析、连续波发生器转阀冲蚀预测与缓解、连续波发生器机械结构与控制系统设计、钻井液信道中信号的反射与叠加几个方面取得了较大研究进展,并且针对信号波形、水力转矩与信号的反射叠加开展了地面水力环路与风洞模拟实验研究。主要研究进展总结如下:1转阀阀口形状设计与优化根据信号与系统的基本理论确定了与连续波发生器转阀设计有关的几个特征量,在最小、最大开度准则的基础上提出了相关系数最大的设计准则;建立了不同阀口形状的转阀通流面积的参数化计算模型,根据最小、最大开度准则和相关系数最大准则建立了转阀阀口形状的优化模型,并进行了优化,理论分析表明优化结果可以获得较理想的信号波形;根据通流面积参数化计算模型的启示,提出了一种理论上可以获得理想正弦波的曲线阀口的设计方法,并进行了风洞实验,结果表明该曲线阀口可以获得较好的正弦波信号;分析了定转子轴向间隙、信号频率对压力波信号品质的影响规律,通过对非定常伯努利方程的分析解释了实验中所发现的压力波信号幅值随频率的增加而有所下降的现象。2连续波发生器的负载特性分析提出了大开度双边节流口射流角的计算方法,为通过理论计算作用在转阀上的水力转矩提供了基础;根据射流的基本理论,在动量矩定理的基础上,推导了作用在转阀上的水力转矩的理论计算公式;并用CFD数值仿真研究了各种因素对转阀水力转矩的影响规律,即,作用在转阀上的水力转矩随信号频率的增加而增加、随定转子轴向间隙、转阀阀瓣个数的减小而增加;分析了不同信号调制方式下作用在转阀上的惯性转矩,结果表明对于相位调制方式惯性转矩与信号频率的平方成正比,与阀瓣的个数成反比;通过CFD数值仿真找出了出现反向轴向力的位置与力的大小,为信号发生器的结构设计提供指导。3转阀的冲蚀预测与缓解本文利用Fluent中的UDF解决了转阀三维冲蚀变形的预测问题,结果表明,考虑冲蚀变形的冲蚀预测在冲蚀的初始阶段与没有冲蚀变形的冲蚀预测结果相差不大,随着阀口冲蚀变形的增加,转子上冲蚀最严重的位置从阀口棱边转移到阀瓣侧壁上;利用固体颗粒在非牛顿流体中的曳力公式来计算固体颗粒在钻井液中的运动轨迹,结果表明,钻井液的非牛顿特性对其中的固体颗粒运动轨迹影响显著;建立了钻井液中粒度小于40微米固体颗粒的冲蚀预测模型,计算结果与离散相模型的结果叠加,可以获得较好的预测结果;针对连续波发生器工作过程中存在的堵塞、冲蚀问题,利用液压流体力学的基本理论,提出了节流口串联的转阀结构形式,研究结果表明,节流口串联的结构形式可以增大转阀的最小通流面积,降低流过转阀的钻井液流速,从而减少堵塞发生的概率,减弱了钻井液与固体颗粒对转阀的冲蚀作用。4连续波发生器的结构与控制系统设计在转阀阀口形状与转阀负载转矩研究的基础上进行了连续波发生器的结构设计;在正脉冲信息传输系统的通信协议基础上构思了用于连续波信息传输的通信协议,并在通信协议的基础上构思了连续波发生器的整体控制流程;进行了驱动电机控制系统的硬件与软件的设计;建立了连续波发生器的动态仿真模型,分析了不同控制方式的动态特性,结果表明包含速度特性的位置闭环控制方式可以获得较准确的相位调制信号和较小的动态转矩。5连续波信号的传输特性分析连续波信号的传输特性是连续波信息传输成败的关键环节,信号衰减是连续波信息传输中的固有问题、不可避免,而信号的反射与叠加却是一把双刃剑,运用、处理不当就会导致信息传输失败,反之则可以改善信息的传输条件,提高信息的传输速率。本文建立了钻井液信道的多层耦合传输模型,分析了多层耦合作用对压力波传播速度的影响;建立了钻头的反射模型,分析了钻头反射对转阀上游信号的影响;建立了复杂管路的传递函数模型,利用所建立的传递函数模型可以组装成不同的钻井液信息传输通道来预测地面接收到信号的频谱,为连续波信号载波频率的选择提供依据。6连续波信息传输系统的模拟实验研究在储建学院多相流实验环路的基础上进行了连续波信息传输系统地面实验环路的设计与改造;进行了风洞实验的相似设计与数据采集系统的软件设计;进行了压力波信号波形实验,实验结果表明:曲线阀口可以获得较理想的压力信号波形,CFD计算结果与实验结果基本相符;进行了作用在转阀上的水力转矩实验,分析了影响转阀水力转矩的几种因素;进行了压力波信号的反射、叠加实验,分析了连续波信号发生器启动过程对压力波信号的影响,分析了压力波信号的主要反射源——钻头处的反射特性,结果表明钻头处的反射边界近似为闭口反射边界。更多还原

【Abstract】 The dissertation is aimed at improving the data transmission rate of MWD drilling fluid continuous-wave information transmission system and some key issues are investigated centered on the design of continuous-wave generator and signal transmission characteristic. The main research achievements include the design and optimization of rotary valve orifice, the load characteristics analysis of continuous-wave generator, the erosion prediction and weakening of rotary valve, the design of continuous-wave generator, the conception and design of continuous-wave generator control system, the reflection and superposition of continuous-wave signal. Finally, the water flow loop and wind tunnel is used to do the surface simulation experiment studies of the signal waveform, hydraulic torque, reflection and superposition of signal. The main works are summarized as follows:1 Design and optimization of rotary valve orificeSeveral characteristic parameters related to the design of rotary valve are determined according to the basic theory of signal and system. The design criterion of maximum correlation coefficient is proposed based on the minimum and maximum opening criterion. The parametric calculation model of rotary valve flow area with different orifice shape is established, after that, the optimization model of the shape of rotary valve orifice is built up according to the criterion mentioned above. The design method of curve orifice which can be used to get the ideal sinusoidal pressure is inspired by the parametric calculation model. The affecting factors of the signal quality are analyzed, and the phenomenon that the pressure amplitude decreases with the signal frequency increase in experiment is interpreted by the unsteady Bernoulli equation.2 Load characteristics analysis of continuous-wave generatorThe calculation mechod for the jet angle of dual side orifice with wide opening is proposed which is the basic of the theory calculation for the hydraulic torque acted on the rotary valve. The theory calculation of the hydraulic torque is done based the angular momentum theorem and jet theory. The effect laws of several factors on the hydraulic torque is studied by the CFD simulation, the results show that the torque increases with the increase of signal frequency, the decrease of the number of valve lobe, and the gap between stator and rotor. The occurred position and value of the reverse axial force is analyzed.3 Erosion prediction and weakening of rotary valveThe prediction of 3D erosion deformation is made by the UDF in Fluent. The result shows that the prediction with deformation is similar with the prediction without deformation in the starting stage of erosion, and then, the maximum erosion occurred position is transferred with the erosion deformation of the orifice increase. The drag force of particle in the Non-Newtonian fluid is used to calculate the trajectory, and get the different results from that in the Newtonian fluid. The erosion model of the particles whose size are smaller than 40μm is established, the prediction result is added to the discrete phase result to get the finally erosion prediction. The series orifice rotary valve is proposed to solve the jam and erosion problems.4 Structure and control system design of continuous-wave generatorcontinuous-wave generator is designed based on the studies of orifice shape and hydraulic torque. The communication protocol of the continuous-wave information transmission system is conceived according to the positive pulse information transmission system, and the control flow of continuous-wave generator is conceived, too. The hardware and software of motor control system is designed, and the dynamic simulation model of continuous-wave generator is built up to analyse the dynamic performance under different control pattern, the results show that the precise phase shift key signal and lower dynamic torque can be attained by using the position closed-loop control pattern including the velocity characteristic.5 Analysis of continuous-wave signal transmission characteristicThe transmission characteristic of continuous-wave signal is the key step in the continuous-wave transmission. The attenuation of the signal is the inherent and inevitable problem, however, the reflection and superposition is a double-edged sword, if it is used properly, the data transmission rate may be increased, otherwise, no signal will be got in the surface. The multilayer coupled waveguide model of the drilling fluid tunnel is built up, and the influence of the coupling effect on the transmission speed of the pressure is analyzed. The influence of the reflection on the upstream signal of the generator is analyzed by establishing the reflection model of the drill bit. The transfer function of complex system is built up and is used to select the carrier frequency for the Continuous-wave information transmission.6 Simulation experiment of continous-wave information transmission systemThe experiment equipments for continous-wave information transmission is designed and rebuilt based on Multiphase Flow Loop. The similar design of the wind tunnel and the software design of the data acquisition system are performed. The signal waveform experiment is performed, the results show that the curve orifice can get good pressure wave and the results of CFD conform to the experiment results. The experiment of hydraulic torque on the rotary valve is performed, and the influence factors on the hydraulic torque are analyzed. The experiment of reflection at the drill bit is done, and the influence of the start stage of the rotary valve on the pressure signal is analyzed. The reflection characteristics of the main reflection source, drill bit, is analyzed, and results show that the boundary condition of the drill bit can be seen as the closed-end boundary.更多还原