## 4 Conclusions  
CCS combined with EOR is a promising technique to reduce CO\({}_{2}\) concentration, alleviate climate change, and promote the transformation to a renewable economy. During the process of reservoir burial, CO\({}_{2}\) will dissolve in the rock pores when it comes into contact with crude oil. After CO\({}_{2}\) dissolves into crude oil, the density of the crude oil will change, which will affect the natural transport of CO\({}_{2}\) in the reservoir, thereby affecting the safety and effectiveness of burial. It is vital to study the thermodynamic properties of mixtures formed by CO\({}_{2}\) dissolution in crude oil. In this work, the experiment was carried out with a VTD at 283-363 K and 10-100 MPa. Experimental density data for CO\({}_{2}\)(1) + \(n\)-decane(2) mixtures with mole fraction x\({}_{1}\) = 0, 0.2030, 0.4434, 0.7589, and 0.8947 were complemented by this work. The experimental data for CO\({}_{2}\) + \(n\)-decane mixtures were compared with values from the literature and showed a good agreement. The experimental densities were fitted with the modified Tait equation with an AAD lower than 0.1%. Based on the experimental data, the isobaric thermal expansivity, isothermal compressibility, and excess molar volume were determined. Overall, this study aims to provide a basis of data and theoretical support for the CO\({}_{2}\) sequestration and resource utilization. Based on the work completed in this study, further work should be carried out on the following aspects:  
1. The composition of crude oil is complex, and single-component hydrocarbons or simple mixtures are not sufficient to represent crude oil. Therefore, it is necessary to study the densities of CO\({}_{2}\) + multicomponent alkane mixtures and CO\({}_{2}\) + crude oil using a high-pressure VTD. 2. In the future, the density equations for CO\({}_{2}\) + alkane mixtures can be further developed by combining the Helmholtz equation of state and mixing rules. Specialized mixing rules and applicable equations can thus be developed. 3. The temperature range, pressure range, and system used in the experimental apparatus can be further expanded. The experimental system used in this work had a temperature range from 283 K to 363 K, and a pressure of up to 100 MPa. In the future, the temperature system can be improved to expand the experiment to a higher temperature range and a higher pressure range. The densities of other mixtures can be obtained by using this experimental apparatus. **Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app14209232/s1](https://www.mdpi.com/article/10.3390/app14209232/s1)]([https://www.mdpi.com/article/10.3390/app14209232/s1](https://www.mdpi.com/article/10.3390/app14209232/s1)), Table S1. Experimental density data of CO\({}_{2}\)(1) + _n_-decane(2) mixtures. Table S2. Isothermal compressibility, isobaric thermal expansivity, and excess molar volume of CO\({}_{2}\)(1) + _n_-decane(2) at various temperatures, pressures, and mole fractions. **Author Contributions:** Conceptualization, [PERSON]; validation, [PERSON] and [PERSON]. ([PERSON]); formal analysis, [PERSON] ([PERSON]) and [PERSON] ([PERSON]); investigation, [PERSON] ([PERSON]); data curation, [PERSON]; writing--original draft preparation, [PERSON]; writing--review and editing, [PERSON], [PERSON] ([PERSON]) and [PERSON] ([PERSON]), supervision, [PERSON] All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by the Open Project Program of Engineering Research Center of Building Energy Efficiency Control and Evaluation, Ministry of Education (Grant No. AHJZNX-2024-). Natural Science Foundation of Jiangsu Province, China (Grant No. BK20230596), Natural Science Research of the Jiangsu Higher Education Institutions of China (Grant No. 22 KJ8470027), CAS Key Laboratory of Cryogenics, TIPC (Grant No.