石油与天然气地质 ›› 2016, Vol. 37 ›› Issue (1): 141-148.doi: 10.11743/ogg20160120

• 技术方法 • 上一篇    

基于核磁冻融技术的煤的孔隙测试研究

郭威1,2, 姚艳斌1,2, 刘大锰1,2, 孙晓晓1,2, 高杨文3   

  1. 1. 中国地质大学(北京)非常规天然气地质评价及开发工程北京市重点实验室, 北京 100083;
    2. 中国地质大学(北京)能源学院, 北京 100083;
    3. 上海纽迈电子科技有限公司, 上海 200062
  • 收稿日期:2015-09-15 修回日期:2015-11-07 出版日期:2016-02-08 发布日期:2016-03-02
  • 通讯作者: 姚艳斌(1978-),男,教授、博士生导师,非常规油气地质。E-mail:yyb@cugb.edu.cn。 E-mail:yyb@cugb.edu.cn
  • 作者简介:郭威(1989-),男,硕士研究生,矿产普查与勘探。E-mail:realgw95@163.com。
  • 基金资助:
    国家自然科学基金项目(41472137);全国优秀博士学位论文作者专项资金项目(201253);山西省煤基重点科技攻关项目(MQ2014-01)。

Research on measurement of pores in coals with NMRC technique

Guo Wei1,2, Yao Yanbin1,2, Liu Dameng1,2, Sun Xiaoxiao1,2, Gao Yangwen3   

  1. 1. Beijing Key Laboratory of Unconventional Natural Gas Geology Evaluation and Development Engineering, Beijing 100083, China;
    2. School of Energy Resources, China University of Geosciences, Beijing 100083, China;
    3. Shanghai Niumag Electronic Technology Co. Ltd, Shanghai 200062, China
  • Received:2015-09-15 Revised:2015-11-07 Online:2016-02-08 Published:2016-03-02

摘要: 采用核磁冻融测孔法(NMRC)和低温氮吸附BJH法对6组不同变质程度煤样进行了孔隙结构和孔体积测试对比实验,首次探讨了将核磁冻融测孔技术应用于煤储层孔隙结构研究的可能性与可行性。研究表明,针对同一煤样,NMRC法测得的总孔体积明显大于BJH法。造成这种现象的原因主要有两个方面:一是,与BJH法相比,NMRC法能够测得更多的封闭孔的孔隙信息;二是,BJH法的计算模型本身存在一定局限性,在测量10 nm以下的微孔和部分中、大孔方面能力有限。不同煤阶煤样的测试结果表明,NMRC法测得的总孔体积随煤岩镜质组反射率增高呈现“先降低后升高”的变化趋势,这与孔隙度随煤阶的变化规律一致;而BJH法的测量结果存在异常值,与上述规律不符。整体上,NMRC法在定量识别煤储层“全孔隙”方面较其他常规方法具有明显的优势;同时,该方法受制样等人为因素的影响较小,是一种可拓展应用于非常规储层孔隙结构的新方法。

关键词: 核磁共振冻融测孔法, 低温氮吸附法, 孔隙结构, 封闭孔,

Abstract: This study compared measurement results of total pore volume and pore size distribution of 6 coal samples with different coal ranks by using the Nuclear Magnetic Resonance Cryoporometry (NMRC) and low-temperature nitrogen adsorption BJH method.Meanwhile,the possibility and feasibility of applying NMRC to analysis of coal pore size distribution were evaluated for the first time. Results show that the total pore volume measured by NMRC is significantly larger than that of BJH method for the same coal sample.This is mainly caused by two factors. Firstly,in comparison with the BJH method,the NMRC can measure more closed pores.Secondly,the BJH model itself has some limitations in calculating the pore volumes of most micropores (<10 nm) and some meso-and macro-pores.Measurement results of coal samples with different coal ranks indicate that the total pore volume measured by NMRC shows a trend of decrease followed by an increase with increasing coal rank.This trend is consistent with the trend of the change of coal porosity with increasing coal rank.In contrast,the total pore volume measured by BJH does not match the trend of the change of coal porosity with increasing coal rank,due to the existence of outlier values in the measurement results of BJH method.Compared with the conventional methods,the NMRC has advantages in quantifying coal total porosity.Moreover,the results of NMRC are less influenced by some artificial factors.Thus,NMRC is a new method that can be applied to the measurement of pore structure of unconventional reservoirs.

Key words: Nuclear Magnetic Resonance Cryoporometry(NMRC), low-temperature nitrogen gas adsorption, pore structure, closed pore, coal

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