## 1 Introduction  
In recent years, the issue of global climate change has become increasingly severe, making the reduction in carbon dioxide (CO\({}_{2}\)) emissions a critical environmental challenge [1; 2; 3]. Strategies such as CO\({}_{2}\) geological sequestration and enhanced oil recovery have garnered significant attention for their potential to both store CO\({}_{2}\) underground and enhance oil extraction efficiency [4]. Shale oil, distinguished from conventional oil by its presence in free and adsorbed states within the microscopic pores of organic-rich rock formations, presents unique technical challenges [5; 6]. These challenges arise from the need for advanced technologies to effectively extract and process oil from such tight formations, differentiating it from conventional oil found in larger pores and fractures. CO\({}_{2}\) throughput technology has been widely used in the development of low-permeability tight sandstone oil and gas reservoirs, but its application in shale oil reservoirs is still in the stage of indoor research and field tests [7]. [PERSON] et al. carried out experiments on the supercritical CO\({}_{2}\) extraction of shale oil, and investigated the effects of the injection pressure, huff and puff rounds, and core properties on the shale oil recovery rate, which increased with the increase in injection pressure; huff time has a great influence on the final recovery rate, and the longer the huff time is, the higher the recovery rate. The shale oil recovery rate increases with the increase in injection pressure. The duration of well stewing has a great influence on the final recovery rate; the longer the duration of the well stewing, the higher the recovery rate. After 36 h, the influence of the duration of well stewing on the recovery rate is weakened; the greater the number of huff and puff rounds, the higher the recovery rate [8]. [PERSON] et al. investigated the characteristics of movable oil components in samples extracted by supercritical carbon dioxide fluids in stratigraphical temperatures and under the conditions of different fluid pressures, and the amount of oil in the samples in the different fugitive states in extraction experiments. The results show that under a certain temperature and different fluid pressures, the fluid can be used to extract the movable oil from the samples. The results show that under certain temperature and fluid pressure conditions, the carbon number of the main components of the movable oil shows a tendency to increase with the increase in the huff and puff extraction duration, and the ability of supercritical carbon dioxide huff and puff to extract movable oil increases significantly with the increase in fluid pressure [9]. [PERSON] et al. carried out single-well cyclic CO\({}_{2}\) injection experiments by using shale oil and Eagle Ford shale samples, and adjusted the injection rate, injection pressure, and number of cycles [10]. In addition, some scholars have used numerical simulations to optimize the parameters of CO\({}_{2}\) huff and puff technology [11]. At present, most studies use conventional methods to accurately measure the shale oil output, and the commonly used CT technology can only be applied in qualitative research, not quantitative research [12; 13; 14]. In recent years, low-field NMR technology has been applied to shale oil reservoir core experiments on a large scale, which can not only enable the study of the microscopic transport of nanoscale pores in shale reservoirs, but also convert the relaxation time in the T2 spectrum into pore size, so as to quantitatively study the mobilization law and characteristics of crude oil in microscopic pores [15; 16; 17; 18; 19; 20]. For example, [PERSON] et al. investigated the CO\({}_{2}\) drive-off process at a continuous increase from 0.7 MPa to \(11\) MPa.