EM-MWD信号在钻柱中传输的影响因素研究  

Investigation of the Factors that Influence EM-MWD Signal Transmission in Drill Strings

作　　者：张浩 毕雪亮[1] 刘维凯[1] 徐月庆 宋明星 邵帅[3] ZHANG Hao;BI Xueliang;LIU Weikai;XU Yueqing;SONG Mingxing;SHAO Shuai(School of Petroleum Engineering,Northeast Petroleum University,Daqing,Heilongjiang,163318,China;Daqing Drilling Engineering Technology Research Institute,Daqing,Heilongjiang,163413,China;Oil Production Engineering Research Institute,Daqing Oilfield of CNPC,Daqing,Heilongjiang,163453,China)

机构地区：[1]东北石油大学石油工程学院,黑龙江大庆163318 [2]中国石油集团大庆钻探工程公司钻井工程技术研究院,黑龙江大庆163413 [3]中国石油大庆油田有限责任公司采油工程研究院,黑龙江大庆163453

出　　处：《石油钻探技术》2021年第6期125-130,共6页Petroleum Drilling Techniques

基　　金：国家自然科学基金项目“页岩气层CO_(2)干法压裂相态控制机理研究”(编号:52004064)资助。

摘　　要：在现有电磁随钻测量(EM-MWD)系统中,钻柱是重要的EM-MWD信号传输信道。为深入了解影响EMMWD信号在钻柱中传输效果的因素,基于等效传输线法对EM-MWD信号信道进行了建模,并使用Ansys软件进行了有限元计算,分析了地层分层情况下不同规格钻柱在交变电磁场中传输的能量损耗以及套管对EM-MWD信号传输的影响规律。研究发现:EM-MWD信号在钻柱中的能量损耗会随着功率和频率增大而增加,当信号频率超过100 Hz时损耗增加更加明显;不同规格的钻柱传输信号的效果不同,但当钻柱壁厚与外径的比为0.08~0.20时,EM-MWD信号传输效果较好;在钻柱上加套管会对EM-MWD信号的传输产生屏蔽作用,影响传输效果,不过当井下EM-MWD信号的发射频率在50 Hz以下时,套管的影响较小。研究结果更加明确了钻柱自身属性对EM-MWD信号传输的影响,可为EM-MWD系统的改进和设计提供参考。In electromagnetic measurement while drilling(EM-MWD)systems,drill strings are important channels for EM-MWD signal transmission.For a better understanding of the factors that influence the EM-MWD signal transmission effect in drill strings,the equivalent transmission line method was used to model the EM-MWD signal channel,and the finite element calculation was made using ANSYS software.With the analysis of strata division,research was conducted on the energy loss of signal transmission by drill strings with different specifications in an alternating electromagnetic field and the influence law of casing on EM-MWD signal transmission.Several findings were obtained in this paper.The increase in power and frequency would enhance the energy loss of EM-MWD signal in drill strings,and when the signal frequency exceeded 100 Hz,the loss grew more evidently.The transmission effect varied for different drill strings,but it was better when the ratio of drill string wall thickness to outer diameter was 0.08-0.20.Adding casing on the drill string would shield the transmission of EM-MWD signal and affect the transmission effect.However,when the frequency of downhole EM-MWD signal was below 50 Hz,the impact of casing is small.The research results further clarified the influence of the drill string's own properties on the EM-MWD signal transmission,which can provide a reference for the improvement and design of the EM-MWD system.

关 键 词：电磁随钻测量 信号传输 钻柱 影响因素 等效传输线法 有限元分析 

分 类 号：TE927[石油与天然气工程—石油机械设备]