Early Assessment of Carbon Dioxide Storage on Seafloor Using Jet-Cooling Technology

It is generally recognized that using depleted oil and gas reservoirs as carbon dioxide (CO2) storage is subject to the risk of CO2 leak through wellbores due to the high corrosivity and mobility of CO2 in gaseous and supercritical states. This work proposes an innovative process called jet-cooling to efficiently deposit and safely store CO2 on the sea floor. It was found that, in typical seawater environments, if the water depth is greater than 4000 m, CO2 can be deposited directly on the sea floor in liquid form. The liquid CO2 will then form hydrates and stay on the sea floor. In the sea water depth ranging from 700 m to 4000 m, CO2 can be injected through jetting-nozzles to reduce its temperature and generate hydrates. The generated hydrates will then settle down on the sea floor due to gravity. The jetting nozzles should be sized based on the required pressure differential and CO2 flow rate. Sonic (critical) flow condition is preferred to maximize the cooling efficiency.