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J4 ›› 2016, Vol. 22 ›› Issue (3): 543-.

• 构造与能源地质学 • 上一篇    下一篇

基于核磁共振不同煤岩类型储渗空间精细描述

刘玉龙,汤达祯,许浩,赵俊龙,李冰洋   

  • 出版日期:2016-09-20 发布日期:2016-10-09

Description of the Storage-Permeability Under the Control of Macrolithotypes Based on the Nuclear Magnetic Resonance

LIU Yulong,TANG Dazhen,XU Hao, ZHAO Junlong,LI Bingyang   

  • Online:2016-09-20 Published:2016-10-09

摘要:

为了深入探究不同煤岩类型储渗空间的特征及其差异性,选取了韩城矿区4种不同煤岩类型的中煤阶样品,采用低
场核磁共振技术,实现了对韩城矿区不同煤岩类型孔裂隙的识别和有效孔隙度差异性的精细描述和定量表征,并在此基础
上基于离心前后累计振幅曲线求取了孔裂隙系统划分的阀值T2C1和T2C2,实现了对不同煤岩类型孔径结构分布的重构。实验
结果表明:不同煤岩类型煤样的T2谱形态差异较大,从光亮煤到暗淡煤,T 2谱由双峰大孔隙型逐渐过渡到双峰小孔隙型,
且T2C截止值和有效孔隙度均呈现出逐渐降低的趋势;并由求取的阀值T2C1和T2C2计算得到的三大孔裂隙系统孔径分布可知,
从光亮煤到暗淡煤,储层的孔裂隙结构由渗流孔型逐渐向综合型和扩散孔型过渡。

关键词: 煤岩类型;储渗空间;低场核磁共振;有效孔隙度;划分阀值

Abstract:

In order to explore the characteristics of storage-permeability and the heterogeneity within the coal macrolithotypes, the
medium-high rank samples of different macrolithotypes in Hancheng mining area, were studied using the low field nuclear magnetic
resonance technique, fine description and quantitative characterization of pore-fracture system and the difference in the effective
porosity within different macrolithotypes in Hancheng mining area have been obtained. Based on the cumulative amplitude curves
before and after centrifugation, the threshold T2C1 and T2C2, which can divide the pore-fracture system, was obtained, and the
reconstruction of proe size distribution of different macrolithotypes was established. The experimental results show that different
macrolithotypes of coal samples have significantly different T2 spectrum, which shows from the bright coal to the dull coal. The T2
spectrum from the double macropore type is gradually transformed to the double micropore type, and both of T2C cutoff value and
effective porosity show a gradually decreasing trend. The distribution of the pore-fracture system, which was obtained by the threshold
of T2C1 and T2C2, show that, from the bright coal to the dull coal, the pore-fracture structure of the reservoir transformed from the seepage
pore type to the comprehension type and the diffusion type.

Key words: macrolithotypes, storage-permeabiliy, NMR, effective porosity, threshold