Speaker
Description
Investigating gas-liquid flow in porous media is of great importance, particularly in the fields of enhanced oil and gas recovery and geological sequestration. CO2 near-miscible flooding is considered an effective method for enhancing oil recovery. However, there is a lack of pore-scale analyses on the flow dynamics and interfacial properties involved in this process, such as wettability, interfacial curvature, and capillary pressure. In this study, X-ray microtomography (micro-CT) was employed to investigate gas and oil phase morphologies and to assess in-situ wettability under near-miscible conditions. Results showed an increase in the contact angle from 66.99° to 72.5° as the injected gas increases. The local contact angles exhibit a distribution both below and above 90°, indicating mixed-wettability characteristics during the experiment. This behavior is attributed to the preferential adsorption of CO2 molecules over oil molecules on the solid surface during the injection process. Additionally, capillary pressure exhibited a tower-shaped curve with a peak near zero, facilitating oil displacement. By the end of the process, a reduction in capillary pressure caused the interfaces to recede into corners, reducing CO2 cluster sizes. Under near-miscible conditions, gas preferentially occupies larger pores, while oil is distributed across pores of varying sizes, contributing to optimal recovery efficiency.
| Country | China |
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