Pore structure and effectiveness of low-permeability reservoirs on the south slope of Dongying depression
YAN Jianping
ZHANG Fan
HU Qinhong
WANG Jun
GENG Bin
TANG Hongming
DONG Zheng
Abstract：To investigate the pore structure of low-permeability sandstone and the conditions to be met by effectiveness reservoirs,core samples from Es3 formation on south slope of Dongying sag were selected as research objects.Based on the types of pore structure,mercury intrusion experiment,nitrogen adsorption experiment and AutoScan analysis were conducted.The results show that the effectiveness of low-permeability sandstone reservoir depends on the pore size distribution and minimum pore size lower limit.Macropores with size ranging from 100 to 10 000 nm develop well in low permeability sandstone.Mesopores,appearing as slit capillary pores,have the most typical size ranging from 3 to 7 nm.Its average pore size is large,while the pore volume and specific surface area are small.The effectiveness of reservoirs is found to be closely related to the homogeneity and intensity of pores;consequently,the lower size limit of macropores in effective reservoirs of Es3 is determined as 160 nm,and more than 90％ pores are larger.The correspondent lower limit for porosity and permeability are around 8.0％ and 0.10 mD.The findings would provide evidence for fluid identification,effective reserves estimation and development in low-permeability sandstone reservoirs.
Keywords：low-permeability sandstonepore structuremercury injectionnitrogen adsorptionautoscaneffective reservoir
Publication Date：2018-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：12( 345-356 )