Oil-Water Flow in Small Diameter Tubes

Experimental validation of theoretical models in two-phase high-viscosity ratio liquid–liquid flows in horizontal and slightly inclined pipes

“…Some examples are reported in the following and summarised in A.1. Andreini et al (1997) used a 1000 mm length, 3 mm or 6 mm internal diameter ðDÞ test section; the authors declared that they performed pressure measurements at the beginning of such test section, which was separated from the inlet by a 'calming section' used to eliminate entrance effects on the test section. The calming section had a length of approximately 200 times the internal diameter: the authors did not evaluate whether such values are sufficiently high to have fully developed flow, but they proposed pressure drop comparison between their experimental data and Brauner (1991) core-annular flow two-fluid model.…”

Oil-water flow regimes in 4-mm borosilicate glass and fluorinated ethylene propylene channels: Effects of wall wettability

“…However, there are competing priorities. Water wetting, or hydrophilic/oleophobic walls, are desirable for reducing pressure drops [4], but the presence of water at the pipe wall accelerates corrosion [2], and thus hydrophobic/oleophilic walls are desirable for reducing corrosion. Oil-water pressure drops and corrosion rates rely heavily on the resulting oil-water flow regime.…”

“…For glass or stainless steel mini-channels, common oil-water flow regimes observed in mini-channels include intermittent (e.g., slug/plug flow), annular (e.g., water at the wall and oil at the core), and dispersed flows (e.g., oil-in-water or water-in-oil) [3,4,6,14,15]. As pipe diameters increase, gravitational effects are more apparent in forming stratified flows (e.g., water in contact with the bottom of the tube and oil in contact with the upper tube wall) [16][17][18].…”

“…A combination of wall materials, oil composition, and flow conditions may affect whether oil or water wets the tube wall [2,4,18,[21][22][23][24]. For certain combinations, inverted annular flows occur in which oil is fully or partially in contact with the tube wall.…”

“…This inverted annular flow condition, combined with oil-selective membranes, may be used to separate oil from formation water after the wellhead. Andreini et al [4] observed dispersed, annular, and intermittent flows in 3.1-mm and 6-mm mini-channels.…”