Carbon dioxide hydrates have attracted considerable attention because of their high gas storage capacity and low-cost carbon capture, but their low formation rate limits their application. Currently, the formation rate of hydrates is mainly improved via physical and chemical methods. Chemical methods promote hydrate formation through the addition of accelerators, which entail low cost and energy. To improve the formation rate of CO2 hydrates, 0.244 g/L sodium dodecyl sulfate (SDS), 0.288 g/L tetra-n-butylammonium bromide (TBAB), and 0.33 g/L nanographite were used, and the effects of different accelerator systems on CO2 hydrate formation were observed. The results show that the single and combined use of promoters SDS, TBAB, and nanographite can shorten the induced CO2 hydrate nucleation time. The combinations of nanographite–TBAB and SDS–TBAB shortened the induced nucleation time better than the single SDS, TBAB, and nanographite systems, while the single SDS and nanographite systems showed better promoting effect compared to the SDS–nanographite system. Thus, the combined accelerators do not necessarily promote the formation of hydrates. Among all accelerator systems, SDS–TBAB showed the shortest induced nucleation time, followed by the other three combinations. Among the single acceleration systems, TBAB showed the largest formation amount, formation rate, and conversion rate in the first 35 min from inflation stoppage. Meanwhile, among the compound systems, SDS–TBAB exhibited the best promoting effect. A comparison of all experiments shows that the accelerator significantly affects the formation amount, conversion, and formation rate of hydrates 35 min before the start of inflation; furthermore, a different effect is observed in the subsequent period. The total production, conversion, and saturation of CO2 hydrates in different accelerator systems show a minimal difference. By providing reference for the rapid formation of CO2 hydrates in a short time, this study promotes the industrial application of hydrate technology.

To investigate the impact of geothermal gradient on the distribution and reserves of hydrate in permafrost regions, it is crucial to utilize the Archie formula to compute hydrate saturation and adjust parameters to enhance the model’s precision under varying temperature gradient conditions. This study formed methane hydrate under four temperature gradients of 0.02 °C/cm, 0.07 °C/cm, 0.11 °C/cm and 0.18 °C/cm, and two sand particle ratios. The values of porosity index (m) and saturation index (n) were fitted according to different conditions. The water saturation and hydrate saturation were then calculated and contrasted with experimental results. Findings indicate that the influence of temperature gradient on the values of m and n is intricate, with n decreasing gradually and m fluctuating with an increase in temperature gradient. The discrepancies between the optimized Archie model and the actual calculated hydrate saturation values ranged from 0.8% to 2.5%, with average errors of less than 3%, proving its applicability. Finally, the optimized Archie model was used to investigate the hydrate saturation and its distribution in different layers, which confirmed the significant effect of temperature gradient on the assessment of hydrate storage and distribution by Archie’s equation.