Study Of Volume Expansion Of CO₂ And Petroleum Fraction（Hydrocarbon）by Raman Spectroscopy Under Geological Sequestration Conditions

With the rapid development of industrialization and the social economy, the air pollution and the greenhouse effect caused by the burning of fossil fuels are threatening the living environment of human being. CO2 is the main gas which leads to greenhouse effect. CO2 emissions of China ranks first in the world. China should reduce16%~17% of CO2 emission by 2015. Geological storage technology is one of the most effective and practical method to reduce the emissions.Especially, storage of carbon dioxide in the exploitation of oil, which can achieve both sequestration of carbon dioxide and enhancing oil recovery.To get accurate solubility and expansion data of carbon dioxide in oil or alkyl is an important basic work for carbon dioxide flooding oil and geological storage.In this experiment, micro visual fused silica capillary reactor was used to instead of the traditional balance kettle, which had the characteristics of corrosion, high temperature and high pressure resistance. It’s used to research the dissolution equilibrium and volume change of CO2 in petroleum system according to realize the carbon dioxide gas injection and the system compression by self-madepressurized gas inlet device. The precise control of temperature and pressure was realized by hot stage and hand pump. And the Raman peak height ratio was determined by in situ Raman spectroscop.At the same time, The OLYSIM software was used to calculate parameters of volume of CO2-petroleum hydrocarbon component system at different temperature and pressure in order to calculate the volume expansion coefficient. Fine linear relationship was obtained between Raman peak height ratio(HCO2/HCnH2n+2) and volume expansion coefficient. It showed that using the Raman peak height ratio(HCO2/HCnH2n+2) of CO2-petroleum hydrocarbon component system to characterize the volume expansion coefficient was feasible in the geological storage conditions. With the increase of the number of carbon atoms, the Raman peak height ratio and the volume expansion coefficient decreases at a certain temperature and pressure.