Enhancing carbon sequestration efficiency and safety through albumin-optimized CO2 hydrate distribution and geological layer stability: An innovative approach

The persistently high global CO2 emissions are exacerbating the greenhouse effect issue. Scientists have explored methods such as carbon sequestration via subsea hydrate formation in response to global warming. However, this method faces a series of challenges when injecting CO2 on a large scale, including the slow formation rate of CO2 hydrates and potential leakage risks. Specially, the direct injection of promoters could lead to excessively high concentrations of additives close to the injection wells. This would consequently accelerate the local hydrate conversion, potentially causing reservoir blockage problems. The current study proposes a novel strategy involving additives that exhibit varying effects with concentrations. The high-concentration areas close to the wellbore can maintain the permeability by inhibiting hydrate formation; while the reduced concentration further away upon gas migration facilitates the rapid formation of CO2 hydrates. We successfully demonstrate the spatial and temporal differences in hydrate formation when using such additives. This can also facilitate the rapid formation of a dense hydrate cap layer over the reservoir, potentially preventing the leakage of CO2 gas. A new type of additive based on egg albumin was developed, which possesses the dual function and exhibits good biocompatibility and specific reservoir stability.