为精确表征中阶煤储层的孔隙特征，以不同煤阶的4组煤样为研究对象，采用压汞、液氮吸附及核磁共振等试验方法，对其特征参数进行定量研究。结果表明，煤储层是以微小孔为主、中孔次之、大孔最少，微小孔为比表面积与孔容积的主要贡献者。中阶煤的孔容积为(3.19～5.21)×10-2 mL/g，比表面积为6.25～9.81 m2/g，孔隙度为5.171%～8.307%，渗透率为(0.008 ～1.253)×10-3μm2。肥煤与焦煤的孔隙是以开放性孔为主，瘦煤与贫煤的孔隙以封闭或半封闭型孔为主；肥煤微小孔隙多为平行板孔，焦煤与瘦煤为双锥管孔或锥形孔，贫煤为尖劈形孔或圆筒孔。随着煤阶的升高，微小孔、吸附孔喉占比逐渐增大，中大孔、渗流孔喉占比逐渐减小，孔隙之间连通性越来越差，渗透率逐渐降低。随着煤阶的降低，比表面积逐渐减小，有效孔隙度逐渐增大，残余孔隙度逐渐减小，孔容积、总孔隙度呈现出先减小后增大的趋势。

In order to accurately characterize the pore of middle-rank coal reservoirs,four sets of coal samples of different coal ranks were taken as the research objects,and the characteristic parameters were quantitatively studied by experimental methods such as mercury intrusion,liquid nitrogen adsorption and nuclear magnetic resonance. The results show that coal reservoirs are dominated by micropores,followed by mesopores and the least macropores. Micropores are the main contributor to specific surface area and pore volume. The pore volume of middle-rank coal is between(3.19～5.21)×10-2 mL/g,the specific surface area is 6.25～9.81 m2/g,the porosity is between 5.171%～8.307%,and the permeability is between(0.008～1.253)×10-3 μm2. The pores of fat coal and coking coal are mainly open pores,and the pores of lean coal and meagre coal are mainly closed or semi-closed pores. The tiny pores of fat coal are mostly parallel plate holes,coking coal and lean coal are double-tapered pipe holes or tapered holes,and meagre coal are split-shaped holes or cylindrical holes. With the increase of coal rank,the proportion of micropores and adsorption pores gradually increases,the proportion of medium and large pores and seepage pores gradually decreases,the connectivity between pores is getting worse,and the permeability gradually decreases. With the decrease of coal rank,the specific surface area gradually decreases,the effective porosity gradually increases,and the residual porosity gradually decreases. The pore volume and total porosity show a trend of first decreasing and then increasing.

0 引言

1 煤样的采集与制备

2 试验方法

   2.1 高压压汞试验

   2.2 液氮吸附试验

   2.3 核磁共振试验

3 试验结果与分析

   3.1 孔隙特征

   3.2 孔容积特征

   3.3 孔比表面积特征

   3.4 孔径分布特征分析

   3.5 孔隙度及渗透率特征

4 结论