本文關(guān)鍵詞： 聲波遙測(cè) 測(cè)井儀器 有限元 壓電換能器　出處：《吉林大學(xué)》2017年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：聲波遙測(cè)技術(shù)是將換能器安裝在油井下,井下?lián)Q能器激發(fā)油管串產(chǎn)生縱向振動(dòng),將聲信號(hào)作為信息的載體,油管串作為聲波傳輸?shù)耐ǖ?將井下傳感器測(cè)得的信息傳輸至地面的無(wú)線傳輸技術(shù)。此技術(shù)相對(duì)傳統(tǒng)獲取井下信息的技術(shù),以成本低、操作方便、可實(shí)時(shí)傳輸?shù)葍?yōu)點(diǎn)得到國(guó)內(nèi)外測(cè)井研究者的廣泛關(guān)注。本文根據(jù)壓電換能器的基本原理,利用COMSOL Multiphysics有限元軟件,設(shè)計(jì)聲波遙測(cè)壓電換能器。首先,通過(guò)對(duì)堆疊式換能器的本征頻率的理論分析和仿真分析結(jié)果進(jìn)行對(duì)比,驗(yàn)證了用有限元軟件仿真分析換能器聲學(xué)性能方法的可靠性。建立聲波遙測(cè)壓電換能器的理論模型,通過(guò)仿真分析,得到壓電換能器結(jié)構(gòu)、材料的改變對(duì)其本征頻率的影響規(guī)律。通過(guò)分析換能器理論模型前幾階次的共振模態(tài),得出換能器一階共振模態(tài)為最佳振動(dòng)模態(tài)的結(jié)論。進(jìn)一步建立聲波遙測(cè)換能器與油管耦合的有限元模型,研究聲波遙測(cè)換能器的頻響特性,發(fā)現(xiàn)換能器的工作頻率為其自身諧振頻率時(shí)聲學(xué)性較為顯著�？疾鞊Q能器壓電元件的結(jié)構(gòu)及壓電材料的選擇對(duì)換能器的聲學(xué)性能的影響,確定換能器壓電元件由10組堆疊的軸向極化方向相反的壓電陶瓷片組成,壓電元件的壓電材料為PZT-4。保證換能器的工作頻率不變的前提下,針對(duì)換能器的發(fā)射功率問(wèn)題進(jìn)行結(jié)構(gòu)優(yōu)化。仿真結(jié)果表明增大換能器轉(zhuǎn)換頭與油管串的接觸面積和空心錐形變徑轉(zhuǎn)換頭結(jié)構(gòu)都可以提高換能器的聲阻抗匹配度,增大換能器的發(fā)射功率。本文設(shè)計(jì)了優(yōu)化的換能器的整體結(jié)構(gòu),實(shí)現(xiàn)可發(fā)射低頻大功率聲信號(hào)的聲波遙測(cè)換能器,對(duì)聲波遙測(cè)系統(tǒng)的設(shè)計(jì)提供了參考性價(jià)值。
[Abstract]:The acoustic telemetry technology is to install the transducer under the well, the downhole transducer excites the tubing string to produce longitudinal vibration, takes the acoustic signal as the carrier of information, and the tubing string as the channel of acoustic wave transmission. Wireless transmission technology that transmits the information measured by underground sensors to the ground. Compared with the traditional technology of obtaining underground information, this technology has the advantages of low cost and convenient operation. The advantages of real-time transmission have attracted wide attention of logging researchers at home and abroad. According to the basic principle of piezoelectric transducer and COMSOL Multiphysics finite element software, the acoustic telemetering piezoelectric transducer is designed in this paper. By comparing the theoretical analysis and simulation results of intrinsic frequency of stacked transducer, the reliability of acoustic performance analysis method using finite element software is verified. The theoretical model of acoustic telemetering piezoelectric transducer is established. Through simulation analysis, the influence of piezoelectric transducer structure and material change on its intrinsic frequency is obtained. The resonant modes of the first several orders of the theoretical model of the transducer are analyzed. It is concluded that the first order resonance mode of transducer is the best vibration mode. The finite element model of acoustic telemetry transducer coupled with tubing is established, and the frequency response characteristics of acoustic telemetry transducer are studied. It is found that the acoustics of the transducer is obvious when the frequency of the transducer is its own resonant frequency. The influence of the structure of the piezoelectric element and the choice of piezoelectric material on the acoustic performance of the transducer is investigated. It is determined that the transducer is composed of 10 groups of stacked piezoelectric ceramic plates with opposite axial polarization. The piezoelectric material of the transducer is PZT-4.The working frequency of the transducer is not changed. The simulation results show that increasing the contact area between the transducer and the tubing string and the structure of the hollow conical variable diameter converter can improve the acoustic impedance matching degree of the transducer. The whole structure of the optimized transducer is designed to realize the acoustic telemetry transducer which can transmit low frequency and high power acoustic signals, which provides a reference value for the design of acoustic telemetry system.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TE927;TE937;P631.83

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