Experimental Study on Multiphase Flow in Fracture-Vug Medium using 3D
Printing Technology and Visualization Techniques
Abstract
Strong heterogeneity and anisotropy exist in fractured-vuggy reservoirs,
resulting in complex flow and relatively low oil recovery. Therefore,
the mechanism of water flooding and gas injection displacement in
fracture-vug medium constitutes a key issue in oil production. In this
study, based on similarity criteria, physical models of fracture-vug
medium are designed and constructed through 3D printing technology.
Then, by combining the LED (light-emitting diode) backlight
visualization method (BVM) and the particle image velocimetry (PIV)
technique, experiments of multiphase flow (i.e., oil-water and gas-oil)
through the printed fracture-vug medium are carried out. During the
experiments, the morphological changes of the fluid interfaces are
captured with BVM, and the velocity field and streamlines of the fluid
in the system are determined by the PIV technique. In addition, we also
investigate various factors affecting the recovery efficiency of
fracture-vug medium, such as injection velocity, gravity, outlet
position, and shape factors. Results show that oil recovery in
fracture-vug medium varies with injection velocity (or Reynolds number),
shape of the vug, and fracture-vug structure. Specifically, the
distribution of remaining oil is affected by the shape of the vug.
Gravity also exerts a great influence on the morphology of bubbles in
the case of gas injection. The present study leads to a better
understanding of multiphase flow in fracture-vug medium and a valuable
experimental dataset.