关键词: 低电阻率油层, 影响因素, 孔隙度, 渗透率, 毛细管压力, 扫描电镜, 计算机层析扫描

Abstract: The results of the conventional and special experiment on the parameters such as porosity,permeability,capillary pressure,wettability,grain size of cores got from low-resistivity formations of A Oilfield were analyzed.The low-resistivity beds in this oilfield were mainly controlled by some factors including high cation exchange capacity of smectite or mixed illite-smectite,high irreducible water saturation in micro-porosity system,existence of trace pyrite.The porosities of conductive beds ranged from 15.0 percent to 28.2 percent,and the permeability values were less than 0.03μm².Although porosity exponent was only 0.530,the lithologic constanta was 6.363.The relationship between resistivity index and water saturation showed a non-liner pattern in dual-logarithm coordinate.The saturation exponent ranged from 1.01 to 1.10.The saturation exponents corrected by cation exchange capcity ranged from 1.56 to 1.65.The CT scanning technique and SEM are useful to determinate the microstructure of rocks and the distribution of pores and minerals.

Key words: low-resistivity formation, influencing factors, porosity, permeability, capillary pressure, scanning electron microscope, CT scanning