【作者】 刘新平；

【导师】 金有海；

【作者基本信息】 中国石油大学 ， 化工装备与过程控制， 2009， 博士

【摘要】 随钻测量(MWD)是近年来发展起来的新的测井技术,可提高大位移井、高难度水平井的工程控制能力和地层评价能力,提高油层的钻遇率。而数据信号传输在随钻测量系统设计中占有重要作用,是系统设计的难点与核心部分。针对MWD数据传输速率低及设计过程中试验难度大等问题,本论文对数字信号处理器(DSP)控制的连续波信号发生器工作机理及风洞模拟试验开展研究,取得了一定的进展和有益的结论。本论文研究采用理论分析、系统设计、计算机仿真以及风洞模拟试验相结合的方法。在对井底遥测信号传输机理、连续波信号发生器工作机理、风洞试验原理等分析研究的基础上,完成了对信号发生器、DSP控制系统、风洞试验模型结构及测控系统的设计,在此基础上进行风洞模拟试验及计算机仿真试验,进而完成了对转阀的优化设计,并建立起连续压力波变频率传输的预测控制模型。论文研究的主要目标是实现更高的数据传输速率、提高数据传输的可靠性以及增强系统的环境适应能力,在理论和试验方法上为我国研制具有自主知识产权的泥浆连续压力波随钻测量系统奠定基础。通过对井底遥测信号的传输机理研究分析表明,泥浆连续波方式代表着无线随钻测量数据传输技术的发展方向。通过分析数据信息的编码方式,选用多进制数字频率调制方式对井下信息进行编码调制,与多进制调相传输方式相比,发送、接收设备以及控制系统相对简单,误码率相对较低,有利于提高数据传输率。制定了地面数据下传和井下数据上传通信协议,为实现变频率的数据传输创造了条件。对井下旋转控制信号发生器工作机理研究表明,压力波动信号的类型和变化规律取决于信号发生器转阀的运动规律,压力波信号的强度取决于转阀的最大流通面积和最小流通面积以及转子和定子之间的间隙。通过对信号的产生及衰减分析计算,完成了连续波信号发生器的模型结构设计和基于DSP的控制系统设计,为发送数据试验提供了条件。DSP控制信号发生器发送数据试验表明,该系统可以满足12Hz~36Hz之间8进制调频数字传输的控制要求。对风洞试验原理的研究分析表明,在实际的风洞试验中只能满足部分相似准则,做到部分模拟。建立了以风洞气相流模拟井下多相流进行连续波信号传输试验的相似模型,并对风洞试验模型结构的流通面积加以校正。研究表明,在风洞中可以模拟非气相流流动条件下的试验研究,通过风洞模拟试验,可以提高试验效率,降低试验成本。通过仿真试验,说明转子叶片厚度、转子与定子之间的间隙、转子的锥度等因素是决定转子扭矩的主要因素,在此基础上给出了转阀优化设计的原则:保证设计的转阀是稳定打开的,同时最大限度地减小转阀的扭矩。对转阀的压差变化仿真结果表明,圆形阀口转阀的压差响应曲线比扇形阀口的压差响应曲线平滑,更近似于正弦波,有利于信号传输。通过风洞模拟试验,证明了通过仿真试验及分析计算所得出的结论是正确的。提出了一种扩展隐层的误差反传(BP)网络训练算法,并与改进的蚁群算法相结合,提高了网络的训练精度和预测精度。由风洞模拟试验,确定适合码元传输的频率范围为12Hz～36Hz,并提出了变频率的数据传输模型,以不同进制的频率调制方式发送数据,在风洞试验段中接收信号并用Matlab仿真处理,以这些数据作为样本,对神经网络进行训练。在实际应用中,用训练好的网络对不同传输方式下的数据接收误码率进行预测,并根据预测结果选择适合的数据传输方式,从而实现更高的数据传输速率,提高工作可靠性,同时增强对环境的适应能力。更多还原

【Abstract】 MWD is a new logging technology which is developed in recent years, it can improve large displacement wells, horizontal wells in difficult engineering control and formation evaluation capabilities, improve the rate of oil drilling encountered. Data signal transmission plays a pivotal role in the MWD system design, and is the core in the system design. For low MWD data transmission rates and the difficult test questions in design process, the paper researched on mechanism of continuous wave signal generator controlled by DSP and the wind tunnel simulation test, made some progress and useful conclusions.In this paper, we explore the use of theoretical analysis, system design, computer simulation and wind tunnel simulation method of combining. At the basis of research on telemetry signal transmission mechanism, continuous wave signal generator working mechanism, the principle of wind tunnel tests and other analytical studies, completed a signal generator, DSP control system, wind tunnel test model of the structure and control system design. On this basis, wind tunnel tests and computer simulation experiments were done, and built a variable frequency pressure wave transmission predictive control model and the optimization algorithm model of impeller design. The main goal of the paper is to achieve higher data rates, improve the reliability of data transmissions, as well as enhance the system environmental adaptability, and to lay a foundation at theoretical and experimental methods for our own independent intellectual property rights of continuous mud wave MWD system.Analysis of the bottom telemetry signal transmission mechanism showed that the mud continuous wave represents the development direction of MWD wireless data transmission technology. By analyzing the data encoding, M-ary frequency modulation mode was selected to modulate the down-hole information. Compared with M-ary phase modulation transfer mode, M-ary frequency modulation mode has relative simple sending and receiving equipment and control system, and relative low bit error rate is conducive to improve data transfer rate. Ground to down-hole and down-hole to ground data transmission protocols were developed,and it created conditions to achieve variable frequency data transmission.Studying on rotation working mechanism of the down-hole pressure control signal generator have shown that the type and changes of the pressure fluctuation signal depend on the movement of the signal generator valve. The strength of the pressure wave signal primarily depends on the largest flow area and the smallest flow area of the rotary valve. Through analysis of signal generation and attenuation, completed the design of the structural model of the continuous wave signal generator and the design of DSP-based control system. It provided sending data conditions for wind tunnel simulation. DSP control signal generator sending data tests show that the system can meet the frequency range of 12Hz~36Hz M-ary digital FM transmission control requirement.Research and analysis on principle of wind-tunnel test show that the actual wind tunnel tests can only meet part of similarity criterion, do part of simulations. Similar models were Set up to do continuous wave signal transmission test by simulating down-hole multiphase flow with gas flow in the wind tunnel, and the flow area of the wind tunnel test model structure was corrected. Studies have shown that the wind tunnel can simulate the test of non-gas flow conditions. Through the wind tunnel simulation, the test efficiency could be improved and the test cost could be reduced.The simulation test shows that the thickness of the rotor blades, the gap between the rotors and stators, the taper of the rotors are the main factors which decide the rotor torque. On this basis the optimal valve design principles are given: To ensure the rotor valve is stable-opened, and to minimize the rotor valve torque. The rotary valve pressure changes simulation results show that the pressure response curves of round-shaped valve are more smoothing than the fan-shaped pressure response curve, and more similar to sine wave. Such characteristics of signal are favorable to signal transmission. The wind tunnel simulation tests proved that the conclusions by simulation tests and analysis computations are correct.A training algorithm was proposed to expand the hidden layer of back-propagation network, and combined with improved ant colony algorithm. The training accuracy and precision of prediction of the network were improved. Wind tunnel simulation tests show that symbol transmission frequency range of 12Hz~36Hz is suitable. A variable-frequency data transmission model was proposed. The data was sent in different M-ary frequency modulation. The signal was received in the wind tunnel test section and simulated and processed with Matlab. These data were trained as samples of the neural network. In practical applications, data reception bit error rate (BER) of different transmission modes will be predicted with well trained network. Suitable means of data transmission are selected according to the results of prediction. In this way, the system could achieve higher data rates, improve job reliability, and enhance the adaptability to the environment.更多还原