Cjg. Darnault et al., Measurement of fluid contents by light transmission in transient three-phase oil-water-air systems in sand, WATER RES R, 37(7), 2001, pp. 1859-1868
Most three-phase flow models lack rigorous validation because very few meth
ods exist that can measure transient fluid contents of the order of seconds
of whole flow fields. The objective of this study was to develop a method
by which fluid content can be measured rapidly in three-phase systems. The
method uses the hue and intensity of light transmitted through a slab chamb
er to measure fluid contents. The water is colored blue with CuSO4. The lig
ht transmitted by high-frequency light bulbs is recorded with a color video
camera in red, green, and blue and then converted to hue, saturation, and
intensity. Calibration of hue and intensity with water, oil, and air is mad
e using cells filled with different combinations of the three fluids. The r
esults show that hue and water content are uniquely related over a large ra
nge of fluid contents. Total liquid content is a function of both hue and l
ight intensity. The air content is obtained by subtracting the liquid conte
nt from the porosity. The method was tested with static and transient exper
iments. Measurements made with the light transmission method (LTM) and sync
hrotron X rays of the static experiment agreed well. In the transient exper
iments, fingers were formed by dripping water on the surface in a two-dimen
sional slab chamber with partially oil-saturated sand. The LTM is able to c
apture the spatial resolution of the fluid contents and can provide new ins
ights in rapidly changing, three-phase flow systems.