钻柱信道内隔声体结构建模与仿真分析.pdf

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1、振动与冲击第32卷第22期JOURNALOFVIBRATIONANDSIIOCKV0l_32No．2220l3钻柱信道内隔声体结构建模与仿真分析李成，井中武，刘钊2樊尚春(1．北京航空航天大学虚拟现实技术与系统国家蘑点实验室，北京100191；2．北京航空航天大学惯性技术重点实验室，北京100191)摘要：在随钻声传输技术中自钻柱底部上行的井下噪声及回波干扰严重降低声信号接收性能。基于低频纵波在声阻抗突变处及周期性管结构信道内的传输特性，设计具有周期性凹槽的隔声体结构。结合信道内噪声特征及隔声带中心频率，比较分析单

2、结构隔声体短节与组合结构隔声体频响特性及隔声量，并将隔声体引入钻柱信道，用钻柱内一维低频纵波传输有限差分算法，时、频域仿真分析隔声体在信道内的隔声性能。结果表明，组合隔声结构n实现较宽的隔声频带，使噪声水平降低20OdB，从而改善信噪比、提高传输速率，为钻柱声遥测系统优化设计提供方法基础。关键词：钻柱；声传输信号；隔声体；建模分析；噪声抑制中图分类号：0421文献标识码：AModelingandsimulationanalysisforanacousticisolationstructureinadrillstri

3、ngchannelLICheng，riNGZhong—WU，Zhao一，FANShang—chun，(1．StateKeyLaboratoryofVirtualRealityTechnologyandSystem，BeihangUniv．，ofAeronautics&Astronautics，Beijing100191，China；2．KeyLabofInertiaTechnoligy，BeihangUniv．，ofAeronautics＆Astronautics，Beijing100191，China)Abstr

4、act：Aimingatthereductionofasoundsignal’Stransmissionperformancecausedbyuplinkdownholenoisesandtheirechoesgenelatedinthebottomofadrillstringwhiledrilling，basedonthetransmissioncharacteristicsoflow一~equencyacousticwavesinmismatchedacousticimpedancesandaperiodicp

5、ipestructuretransmissionchannel，anacousticisolationstructurewithaperiodicgroovestructurewasdesignedhere．Accordingtothenoisefeaturesandthecentralfrequencyofacousticisolationstopbandinadrillstringchannel，thefrequencyresponsefeaturesandsoundreductionindexesforasi

6、ngleacousticisolatorandacombinedacousticisolatorwerecompared．Then，thetwoacousticisolationstructureswereinducedintothedrillstringchanne1．Byapplyingafinite—differencealgorithmfortheone—dimensionalpropagationoflongitudinalwavesalongthedrillstring，theacousticisola

7、tionperformancesofthetwoacousticisolatorsinthedrillstringchannelwereanalyzedwithtimedomainandfrequencydomainsimulations．Thesimulationresultsshowedthatthecombinedacousticisolatorcanachieveawideracousticisolation~equeneybandwidthwitha20～40dBreductionofnoise．andl

8、eadtotheimprovementofsigna1．to．noiseratioandtheincreaseintransmissionrate，theresultsprovideamethodologicalfoundationforoptimaldesignofacoustictelemetrysystems．Keywords：drillstring；