RESUMO
CO2-based enhanced oil recovery is widely practiced. The current understanding of its mechanisms largely focuses on bulk phenomena such as achieving miscibility or reducing oil density and viscosity. Using molecular dynamics simulations, we show that CO2 adsorption on calcite surfaces impedes decane transport at moderate adsorption density but enhances decane transport when CO2 adsorption approaches surface saturation. These effects change the decane permeability through 8 nm-wide pores by up to 30% and become negligible only in pores wider than several tens of nanometers. The strongly nonlinear, non-monotonic dependence of decane permeability on CO2 adsorption is traced to CO2's modulation of interfacial structure of long-chain hydrocarbons, and thus the slippage between interfacial hydrocarbon layers and between interfacial CO2 and hydrocarbon layers. These results highlight a new and critical role of CO2-induced interfacial effects in influencing oil recovery from unconventional reservoirs, whose porosity is dominated by nanopores.
RESUMO
For an electrohydrodynamic (EHD) jet, variables such as the direction of the meniscus and the ejection stability need to be analyzed. Thus, the EHD jet should be observed three-dimensionally (3D) because the variables can only be obtained in the 3D field, especially in unstable modes. However, if the 3D field is reconstructed from multi-directional binary images, eliminating reconstruction errors caused by invisible areas is almost impossible, even when using a tomographic technique. To solve this problem, a new 3D reconstruction method including an ellipse estimation was developed in this study. The method was verified by numerical simulation and applied to estimate the jetting flow rate and the direction of an ethanol droplet ejected from a nozzle according to a voltage.