Interfacial tension was measured for hexane + water, heptane + water, octane + water, nonane + water,
decane + water, undecane + water, and dodecane + water, using the emergent drop experimental
technique with a numerical method based on a fourth degree spline interpolation of the drop profile. The
experimental equipment used to generate the drop consists of a cell with a stainless steel body and two
Pyrex windows. The inner cell was previously filled with water. A surgical needle (at the bottom of the
cell) was used to introduce the organic phase into the cell (forming the emergent drop). Water was used
to keep the temperature constant inside the cell (between 10 °C and 60 °C). The cell was illuminated
from the back using a fiber optic lamp and a diffuser. A video camera (with a 60 mm microlens and an
extension ring) was located at the front window. The emergent drop image was captured and sent to the
video recording system. The cell and the optical components were placed on an optical table with vibration
isolation legs. A new correlation was found to predict interfacial tension (γ) as a function of temperature
(t) and the number of carbon atoms (n) with a deviation of less than 0.05% from experimental values.
To estimate the most important flow variables in reservoir engineering, such as the relative permeability, it is required to know with high precision, other variables such as saturation, pressure drop of each phase, and porous media data such as porosity and absolute permeability. In this study, experimental tests were performed inside a glass micromodel using gas-liquid two-phase flow in steady-state conditions. The liquid-phase flow and the pressure drop of the porous media were determined. Additionally, the flow development inside the porous media was visualized using a high-speed video camera system. These pictures were recorded at 500 fps, and they were used to compute the phase saturation and the gas velocity in the glass micromodel. The visualization was performed in three regions of the glass micromodel demonstrating that saturation gradients were not present. The effect of the capillary number was studied over the gas-liquid relative permeability curves and on the flow mechanisms. It was concluded that high flow rates minimize edge effects, that the capillary number modifies the relative permeability values and the flow patterns inside the micromodel, and that the high-speed visualization is an efficient and accurate technique to determine saturation values and to study the flow patterns in transparent porous media such as glass micromodels.
The interfacial tension (IFT) between decane and aqueous solutions of Triton X-100 was determined by the pendant-drop technique, and the effects of the temperature, pressure, surfactant concentration, droplet growth rate, and size were studied. Three aqueous solutions of surfactant were used (0.48×10 −4 mol · L −1 , 0.96×10 −4 mol·L −1 , 1.43×10 −4 mol·L −1 ), and the experiments were performed at (2, 3, and 4) MPa and at (30, 40, and 50) • C. As expected, the alkane drop changed its shape, and the IFT of the system decreased as the surfactant adsorbed onto the interface, until the drop finally separates from the capillary, in a maximum time of 2120 s. According to the results, the influence of temperature on the IFT is inversely proportional to the surfactant concentration, because when the concentration increases, the temperature has little effect on it. It was also noticed that the effect of pressure on the IFT at lower surfactant concentrations is less significant than at higher concentrations. When the temperature decreases, the pressure reduces its effect on the IFT, as occurs with systems at 30 • C. The droplet growth rate does not significantly affect the IFT value, while its size does; therefore, when transient studies are carried out, it is required to control the drop size.
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