基于核磁共振技术的低阶煤储层孔隙特征研究

发布时间：2018-04-26 03:35

本文选题：低阶煤储层 + 核磁共振　；参考：《煤炭科学技术》2017年04期

【摘要】：为了探究低阶煤储层孔径及有效孔隙度特征,有利于提高煤层气的开采效率,基于核磁共振试验,分析了煤储层的横向弛豫T2谱、微小孔孔径分布及有效孔隙度特征。结果表明:试验的低阶煤的横向弛豫T2谱存在3种峰的类型:单峰型、双峰型及三峰型,谱峰T2弛豫时间分别处在0.1~1.0 ms、10 ms左右以及70 ms处,得出了煤样主要以微小孔发育为主;计算出了试验的低阶煤的表面弛豫率为1.51×10~(-8) m/ms左右和微小孔孔径与T2弛豫时间的转换系数C为4.53×10~(-8)m/ms,进而得出微小孔孔径分布曲线;获得了有效孔隙度平均值为0.97%,认为有效孔隙度大小与固定碳含量呈正相关关系,与灰分及挥发分含量呈负相关关系,可断定该煤储层孔隙连通性较差,且有效孔隙度较低,不利于煤层气开采。
[Abstract]:In order to explore the characteristics of pore size and effective porosity of low rank coal reservoir and improve the recovery efficiency of coalbed methane, the transverse relaxation T2 spectrum, pore size distribution and effective porosity characteristics of coal reservoir are analyzed based on NMR test. The results show that there are three types of peaks in the transverse relaxation T2 spectrum of the low rank coal tested: single peak type, double peak type and three peak type, and the T 2 relaxation time of the spectrum peak is about 0.1 ~ 1.0 Ms ~ 10 Ms and 70 Ms, respectively. The surface relaxation rate of the tested low-rank coal is about 1.51 脳 10 ~ (-8) m/ms and the conversion coefficient C between the pore size and the T _ 2 relaxation time is 4.53 脳 10 ~ (-1) ~ (-8) m / m ~ (-1), and the pore size distribution curve is obtained. The average effective porosity is 0.97. It is considered that the effective porosity is positively correlated with the fixed carbon content, and negatively correlated with the ash and volatile content. It can be concluded that the porosity of the coal reservoir is poor and the effective porosity is low. It is unfavorable to the exploitation of coalbed methane.
【作者单位】：中国矿业大学(北京)地球科学与测绘工程学院;
【基金】：全国油气资源战略选区调查与评价资助项目(1211302108025-2) 国家自然科学基金资助项目(41572141,41402134)
【分类号】：TE311

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