Influence of glycol ether additive with low molecular weight on the interactions between CO2 and oil: Applications for enhanced shale oil recovery.

The high-efficient development of shale oil is one of the urgent problems in the petroleum industry. The technology of CO₂ enhanced oil recovery (EOR) has shown significant effects in developing shale oil. The effects of several glycol ether additives with low molecular weight on the interactions between CO₂ and oil were investigated here. The solubility of glycol ether additive in CO₂ was firstly characterized. Then, the effects of glycol ether additives on the interfacial tension (IFT) between CO₂ and hexadecane and the volume expansion and extraction performance between CO₂ and hexadecane under different pressures was investigated. The experimental results show that diethylene glycol dimethyl ether (DEG), triethylene glycol dimethyl ether (TEG), and tetraethylene glycol dimethyl ether (TTEG) all have low cloud point pressure and high affinity with CO₂. Under the same mass fraction, DGE has the best effect to reduce the IFT between hexadecane and CO₂ by more than 30.0%, while an overall reduction of 20.0%e30.0% for TEG and 10.0%e20.0% for TTEG. A new method to measure the extraction and expansion rates has been established and can calculate the swelling factor accurately. After adding 1.0% DEG, the expansion and extraction amounts of CO₂ for hexadecane are respectively increased to 1.75 times and 2.25 times. The results show that glycol ether additives assisted CO₂ have potential application for EOR. This study can provide theoretical guidance for the optimization of CO₂ composite systems for oil displacement. [ABSTRACT FROM AUTHOR]