Large-scale experimental study on marine hydrate-based CO2 sequestration

In recent years, the global climate issues caused by CO2 have become increasingly severe, triggering a series of technological reforms aimed at decarbonization. Among these, the marine hydrate-based CO2 sequestration (HBCS) technology has shown great potential. However, the current research on HBCS mainly relies on smallscale experimental studies, and the corresponding conclusions lack practical applications. Therefore, this paper independently developed a large-scale HBCS experimental system with a 1700 L high-pressure reactor, which has a total of 80 temperature measurement points and 80 pressure measurement points, as well as 9 horizontal wells and 9 vertical wells. This paper utilizes this system to conduct HBCS research on water-saturated and coarse-grained quartz sand at 11 MPa pore pressure through vertical and horizontal wells. The experimental results indicate that under conditions of low temperature (7 oC), high flow rate (20 mL/min), and horizontal well, the water to CO2 hydrate conversion (39.83 %), total amount of CO2 sequestration (14296.64 L/STP) and HBCS (12790.48 L/STP) are the highest, corresponding to the minimum reservoir space for sequestering one million tons of CO2. Furthermore, the influence area for HBCS in vertical well is approximately 9000 times the cross-sectional area of the well. This research can provide theoretical references for marine HBCS.