井下极端条件核磁共振探测系统研制

Design and implementation of NMR system in downhole extreme conditions

简要介绍2005年至今笔者课题组在井下极端条件核磁共振探测系统研制方面的成果。这里的极端条件是指:高温、高压、仪器体积受到严格限制、测量时处于运动状态、被测样品处于探头之外、低场、低信噪比等。处于井下极端条件的核磁共振探测与常规条件下的核磁共振探测很不相同,需要特殊的探头和测控系统,对降噪及资料处理和解释也提出一系列技术和工艺要求。围绕井下极端条件核磁共振探测的关键科学问题、技术问题、工程问题、工艺问题,介绍解决方法和相应进展,包括探测系统的基本组成与研发流程,探头设计与实现,测控系统设计与实现,降噪方法与效果,数据采集及处理软件的设计与实现。设计制作并测试偏心型和居中型两种探头、全套电子线路及降噪方法、采集与处理软件。所研制的探测系统已经投入到工程化应用,提升了中国石油工业高端技术的水平。

The design of nuclear magnetic resonance （NMR） system in downhole extreme conditions was briefly summarized. The extreme conditions here include environments with high temperature （up to 175 ℃ ） and high pressure （up to 68. 95 MPa） in a well bore, very restricted space for system size, measurements done in moving conditions, sample outside of the probe with low magnetic field and low signal-to-noise ratio （SNR）. NMR systems in downhole extreme conditions are very different from the conventional ones, so the probe and control systems require special consideration. Noise reduction, data processing and interpretation are equally important. The key issues of design and implementation of downhole NMR systems, including design of components of the NMR system and signal flow, design and implementation of probe, monitoring and con- trol system, noise reduction methods and design and implementation of data acquisition and processing software, were dis- cussed. The NMR system proposed and designed was delivered to engineering and application stage, and improved high end instrumentation and technology for China petroleum industry.