压汞法与气体吸附法联用分析沈352井致密储层岩石孔隙结构

Abstract

油气储层孔隙直径分布研究的主要技术手段有压汞法、气体吸附法等。压汞法常用于测试连通的中孔和大孔的孔隙结构。氮气吸附法侧重于表征微孔和中孔的孔隙结构。仅靠一种方法不能给出孔结构的所有信息。因此，压汞法和气体吸附法相结合分析全孔隙结构特征尤为重要。本文将两种测试方法联用，分析沈352井致密储层岩石(油页岩、泥质泥晶云岩、云质泥岩)全孔隙结构的孔径分布特征，认为：油页岩中孔隙直径小于100 nm的占70%左右；孔隙直径呈现“三个峰”，第一个主峰为5~30 nm，次峰30~200 nm，第三个峰1000~3000 nm。泥质泥晶云岩中孔隙直径小于100 nm的占75%左右；孔隙直径略现“二个峰”，第一个主峰为2~30 nm，次峰50~100 nm。含云泥岩或云质泥岩中孔隙直径小于100 nm的占90%以上；孔隙直径以小于15 nm为主。 Mercury injection and gas absorption analytical methods are the main technical means of pore diameter distribution diagram of Petroleum Reservoir. Mercury injection method constantly is used for determination of connected middle pore and macropore, and gas absorption method is used for determination of Microporous and middle pore. Based on combination of mercury injection and gas absorption analytical methods, the complete pore diameter distribution diagram of tight reservoir rock can be obtained. By the use of the combination of two methods in tight reservoir rock of the well of shen352, the author makes a conclusion: Pore diameter which is less than 100 nm of oil shale is about 70%; it has “three peaks” at 5 - 30 nm, 30 - 200 nm and 1000 - 3000 nm. Pore diameter which is less than 100 nm of pelitic micrite dolomite is about 75%; it slightly presents “two peaks” at 2 - 30 nm, 50 - 100 nm. Pore diameter which is less than 100 nm of dolomitic mudstone is more than 90%; the main range of pore diameter of this rock is less than 15 nm.