作者：张嘉伟, 宋公仆, 薛志波, 王光伟

作者单位：中海油田服务股份有限公司油技事业部油田技术研究院, 北京 101149

关键词：核磁共振; 微弱信号; 前置放大; 高压隔离; 高压泄放

摘要：

核磁共振测井中实际接收到的信号十分微弱,为能够有效地提取回波信号,该文提出一种微弱信号接收链路的设计方案,并辅以隔离与泄放电路以确保接收链路在探头高压发射与低压接收中能够很好地完成对微弱信号的预处理,且在最后对该接收链路噪声水平进行分析与实际测试。目前该接收链路已经成功应用于实际井下仪器中,并取得了较好的应用效果。

Design of receiving circuits based on NMR logging

ZHANG Jia-wei, SONG Gong-pu, XUE Zhi-bo, WANG Guang-wei

The Technical Center of China Oilfield Services Limited, Beijing 101149, China

Abstract: The actual signals receiving from NMR(nuclear magnetic resonance) logging is very weak. In order to pick up the echoes effectively, a design of receiving circuits for weak signals was proposed. An auxiliary part of decoupler and discharge circuits was used to preprocess the echoes perfectly when high exciting voltage and weak receiving signals upon the antenna. Noise of the receiving circuits was analyzed and tested practically. At present, this receiving circuit is used in actual downhole equipment with satisfactory results.

Keywords: NMR; weak signals; pre-amplifier; high voltage isolation; high voltage discharge

2012, 38(3): 94-97  收稿日期: 2011-5-4;收到修改稿日期: 2011-7-25

基金项目: 中海油企业发展基金项目(H04010701W070552)

作者简介: 张嘉伟(1982-),男,工程师,主要从事核磁共振测井仪器研制工作。

参考文献

[1] Coates G,肖立志,Prammer M. 核磁共振测井原理与应用[M]. 孟繁莹,译. 北京:石油工业出版社,2007.
[2] 邵维志,庄升,丁娱娇. 一种新型核磁共振测井仪:MREx[J]. 石油仪器,2004,18(2):36-39.
[3] Pollak V L, Slater R R. Input circuit for pulsedNMR[J]. The Review of Scientif ic Instruments,1966,37(3):268-272.
[4] 肖立志. 核磁共振测井资料解释与应用导论[M]. 北京:石油工业出版社,2001.
[5] 戴逸松. 微弱信号检测方法及仪器[M]. 北京:国防工业出版社,1994.
[6] 康华光. 电子技术基础[M]. 武汉:高等教育出版社,1999.
[7] 肖立志. 核磁共振成像测井与岩石核磁共振及其应用[M]. 北京:科学出版社,1998.
[8] 肖立志,谢然红. 核磁共振测井仪器的最新进展与未来发展方向[J]. 测井技术,2003,27(4):265-269.