北大巴山逆冲推覆带发育大量富有机质泥板岩，为研究该区极浅变质泥板岩的微观孔隙结构，通过低温氮气物理吸附、高压压汞、氩离子抛光-场发射扫描电镜(Ar-FESEM)、X-射线衍射(XRD)等试验，定量、定性表征下寒武统鲁家坪组富有机质泥板岩微观孔隙结构特征和影响因素。试验结果表明，鲁家坪组泥板岩微观孔隙结构具有强烈的非均质性，孔径范围分布广且组合形式多样。紫阳地区鲁家坪组泥板岩的微孔、介孔、大孔发育程度相当或更偏向于介孔-大孔；岚皋地区以微孔发育为主导，辅以发育介孔和大孔。鲁家坪组泥板岩孔隙大小和类型与岩石矿物组分密切相关，石英、长石、碳酸盐岩等脆性矿物相关孔隙类型以粒内溶蚀孔、边缘孔缝、粒间孔为主且多被黏土矿物、有机质充填，脆性矿物颗粒挤压黏土矿物和有机质内部微孔、介孔，致使其改造甚至是闭合，约束孔隙体积发育；黏土矿物相关孔隙类型以层间孔缝为主，孔径大小以介孔为主，是提升鲁家坪组孔隙体积的主要孔隙类型；有机质孔是鲁家坪组微孔孔隙主要类型，提供了大量比表面积，是气体吸附的主要场所。鲁家坪组泥板岩的微观孔隙结构利于天然气吸附保存，但总体孔喉细小、连通性较差，不利于游离气运移。

A large amount of very low-grade epimetamorphic organic-rich shale of Lujiaping Formation developed in northern Dabashan thrust belt. However,the study on nature gas generating conditions such as hydrocarbon generation potential and reservoir conditions of it is very poor. In this study,some experiment technical means such as low-temperature nitrogen gas adsorption,high-pressure mercury injection，argon ion figuring-field emission scanning electron microscope(Ar-FESEM) and X-ray dimaction(XRD) were carried out to analyze the pore structure of low-grade epimetamorphic organic-rich shale and development factors. The results show that the low-grade epimetamorphic shale of Lujiaping Formation is intensity heterogeneity with multiple-porosity systems. The range of pore size is wide and the combination is diverse. The development of macropore,mesopore and micropore is comparable or more inclined to macropore and mesopore in Ziyang Area. That in Langao Area,the micropore is dominant and macropore and mesopore are complementary. The pore type is closely related to the rock mineral composition. The pore types related to the brittle minerals as quartz,feldspar and carbonate are dissolution pores in grains,gaps between grains and intergranular pore. However,those pores are usually filled by clay minerals and organic matter and the pores in clay and organic matter would be reformed and even closed by the mutual squeezing of brittle minerals that restrained the pore volume development. The pores related clay minerals are interlayer pores which are mainly mesoporous that increase the pore volume of Lujiaping formation. Organic pores are main types of micropores in Lujiaping formation,which provide a large amount of specific surface area for gas adsorption. The micropore structure of low-grade epimetamorphic organic-rich shale is good for nature gas adsorption and preservation but not for migration and accumulation of free gas because of small pore throat and poor pore connectivity. 

0 引言

1 地质概况

2 样品取样与试验

3 试验结果与讨论

   3.1 微观孔隙类型

   3.2 等温曲线特征及孔径分布

   3.3 毛管压力曲线特征及孔径分布

   3.4 矿物组分对孔隙发育的影响

4 结论