摘要
临县地区是当前煤系致密砂岩气勘探的潜力区域。基于铸体薄片、扫描电镜、孔渗测试和高压压汞等实验手段,对该地区40块岩心样品孔隙结构进行综合表征;在此基础上,根据分形理论,对砂岩孔隙分形特征进行了系统的研究。结果表明:(1)研究区煤系致密砂岩储层物性较差,孔隙结构复杂,喉道狭窄,孔隙间连通性差,储集空间以次生孔隙为主,粒间孔隙较少。(2)压汞曲线分两类:I类,呈平台状,排驱压力低,效喉道半径分布在0.002 5~0.63μm;II类,排驱压力较高,曲线向右上方偏移,喉道半径集中在0.002 5~0.063μm之间。(3)致密砂岩孔隙结构具有多段分形特征。分形维数与空隙结构参数之间存在良好的相关性,分形维数可以很好地表征孔隙结构的复杂程度和非均质性。
The Linxian area is a potential coal measures tight sandstone gas exploration area. Based on experimental means of casting thin section,SEM,permeability and high-pressure mercury intrusion tests have carried out pore structural features integrated analysis for 40 core samples from the area. On this basis,according to fractal theory carried out systematic study of sandstone fractal characteristics. The result has shown that( 1) the coal measures physical property of tight sandstone reservoir in study area is rather poor with complex pore structure,narrow porethroat and poor connectivity among pores,reservoiring space is mainly secondary pores,less intergranular pores;( 2) mercury intrusion curves can be divided into two types: type I,platform like with low displacement pressure,porethroat radius 0. 002 5 ~ 0. 063μm; type II,higher displacement pressure,curves shifting upper right,porethroat 0. 002 5 ~ 0. 063μm;( 3) pore structures of tight sandstone have multisegment fractal characteristics. Good correlation exists between the fractal dimension and pore structure parameters,fractal dimension can characterize pore structural complexity and anisotropy.
出处
《中国煤炭地质》
2017年第10期30-35,56,共7页
Coal Geology of China
基金
国家自然科学基金项目(41572141)
中国地质调查局地质调查资助项目(DD20160187)
关键词
孔隙结构
分形特征
煤系致密砂岩
高压压汞
临县地区
pore structure
fractal characteristics
coal measures tight sandstone
high-pressure mercury intrusion
Linxian area
