Краткое описание

The major objective of this work is to investigate the Joule−Thomson effect (J−T effect) of CO₂ leakage through vertical porous pathways. A one-dimensional depressurization process model is established, in which the Span−Wagner equation is employed to describe the thermophysical properties of CO₂. The effects of heat exchange between CO₂ and the surroundings, pressure drop, and the permeability of leaky pathways on the J−T effect are presented for different leakage scenarios. The results indicate that a large temperature drop is present along the leaky pathway due to the drastical variation of the thermophysical properties of CO₂. Based on the hierarchical leakage scenarios, the J−T effect always leads to the CO₂ temperature profile approaching the CO₂ saturation line, whereas the heat exchange between CO₂ and the surroundings induces the CO₂ temperature profile inclining to the geothermal temperature distribution. A remarkable temperature drop is observed due to the larger pressure drop, although the increase in the permeability of the leaky pathway mitigates the influence of heat transfer on the J−T effect. For the direct leakage scenario, a sharp temperature drop of CO₂ appears in the near-surface segment. The inlet depth of the leaky pathway primarily determines the pressure drop, the temperature drop, and the flow rate of CO₂ leakage. For different scenarios of CO₂ leakage, an in-depth data analysis of the CO₂ depressurization process will provide insight into the monitoring and evaluation of CO₂ leakage.