不同饱和度砂岩渗透率、孔隙度随应力变化规律研究

发布时间：2018-06-03 02:09

本文选题：岩石力学 + 低渗透砂岩　；参考：《岩石力学与工程学报》2017年03期

【摘要】：制备含水饱和度为0%~70%的砂岩岩样,利用低渗透岩石气体渗透测试装置,对不同含水饱和度的砂岩岩样进行气渗试验,测量其在不同围压和渗压下的渗透率以及对应围压下的孔隙度,分析和讨论不同含水饱和度低渗透砂岩渗透率、孔隙度与应力三者之间的关系。得到以下结论:含水饱和度低于50%的低渗透砂岩,其气测渗透率随孔隙压力的增大而减小,含水饱和度高于50%的低渗透砂岩,其气测渗透率的变化规律相反;气测渗透率与孔隙压力符合指数函数关系;随着含水饱和度的增大,气测渗透率对孔隙压力变化的敏感性减少,且气测渗透率对孔隙压力变化的敏感性随着孔隙压力的增大而增大;绝对渗透率、孔隙度与围压均呈指数函数关系;随着含水饱和度的增大,绝对渗透率对围压变化的敏感性增大,对孔隙度变化的敏感性减小,且绝对渗透率和孔隙度对围压变化的敏感性均是随着围压增大而减小;低渗透砂岩的孔隙度与其绝对渗透率的变化成正相关,孔隙度的少量降低即能引起其绝对渗透率的大幅度下降;绝对渗透率与孔隙度成指数函数关系;随着含水饱和度增大,绝对渗透率对孔隙度变化的敏感性增强,且随着孔隙度的增大,绝对渗透率对孔隙度变化的敏感性也逐渐增强。
[Abstract]:To prepare sandstone samples with water saturation of 0%~70%, the gas permeability test of sandstone samples with different water saturation is carried out by gas permeability test device of low permeability rock. The permeability and porosity under confining pressure are measured with different confining pressure and seepage pressure. The permeability and porosity of different water saturation and low permeability sandstone are analyzed and discussed. The following conclusion is drawn: the gas measurement permeability is lower than 50% in low permeability sandstone, and its gas permeability is decreased with the increase of pore pressure, and the water saturation is higher than 50% in low permeability sandstone. The variation of gas permeability is in the opposite direction; the gas permeability and pore pressure are in accordance with the exponential function of the pore pressure; with water cut, the gas permeability is in accordance with the pore pressure. The sensitivity of gas permeability to pore pressure decreases with the increase of saturation, and the sensitivity of gas permeability to pore pressure increases with the increase of pore pressure; absolute permeability, porosity and confining pressure are exponentially functional, and the sensitivity of absolute permeability to confining pressure increases with the increase of water saturation. The sensitivity of the porosity to the change of porosity decreases, and the sensitivity of the absolute permeability and porosity to the confining pressure decreases with the increase of confining pressure; the porosity of the low permeability sandstone is positively correlated with the change of absolute permeability, and a small decrease in porosity can cause a substantial decrease in absolute permeability; absolute permeability and porosity. With the increase of water saturation, the sensitivity of absolute permeability to porosity is enhanced, and with the increase of porosity, the sensitivity of absolute permeability to porosity is also increased.
【作者单位】：河海大学港口海岸与近海工程学院;河海大学岩土工程科学研究所;
【基金】：国家自然科学基金项目(11272113,11572110) 中央高校基本科研业务费项目(2016B05314)~~
【分类号】：TU45

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