Towards a Long-Term Solution to Carbon Dioxide Storage

The growing threat of global warming caused by the burning of fossil fuels has led scientists to explore solutions such as underground injection of CO₂. Possible alternatives for CO₂ storage include the oceans, deep saline reservoirs and depleted oil and gas reservoirs. One of the key issues to be addressed with regard to underground reservoir storage is CO₂ loss from storage due to leakage through faults and fractures in the geological structure. Thus, while flow of CO₂ gas and water or oil through fractures is anticipated to occur, there is a high degree of uncertainty regarding prediction of flow phenomena. Complicated gas-liquid flow phenomena in geologically varied domains are also expected during CO₂ injection. This paper presents the experimental and numerical results on the two-phase flow phenomena in a simulated single fracture. The bubbly flow in the fracture was obtained and bubble properties were studied. It is found that the bubbly flow features frequent bubble coalescence. The influence of flow rate of both phases on the bubble size and velocity is also presented. A transient laminar model was established to simulate a case of an experimental bubbly flow. In order to reconstruct the two- phase interface, a geometric reconstruction scheme of volume of fluid (VOF) model was adopted. Simulated bubbly flow has the same feature observed from experimental work.