Directional motion of the foam carrying oils driven by the magnetic field

Abstract

Foams are substances widely used the foam flooding technology, which aim to greatly improve the residual oil recovery. In the present study, we perform a comprehensive investigation on the oil removal process driven by the foam embedded with magnetic particles, under the action of the magnetic force. The experiment shows that the addition of magnetic particles has little effect on the stability of the foam. During the motion of the foam, its maximum displacement and maximum acceleration are fully explored. Such factors as the volume of the foam, the volume of the oil droplet, the mass concentration of magnetic particles, and the Young's contact angle of surfactant on solid are surveyed in detail. The function curves of the maximum displacement and the maximum acceleration with respect to these variables are obtained in the experiment, and the selection of some optimal parameters is advised. Moreover, the dimensional analysis has been conducted and several scaling laws are given, which are in agreement with the experimental results. These findings are beneficial to understand the oil displacement with the aid of magnetic field, which also provide some inspirations on drug delivery, robots and micro-fluidics.

Figure 1

Schematic diagram of the experimental setup.

Figure 2

The function curve of the half-life of the foam with respect to the concentration of the magnetic particles.

Figure 3

Magnetic force distribution map. (a) The cloud map of magnetic force per unit mass of magnetic particles, (b) The relationship between magnetic force and the distance D.

Figure 4

Snapshots of the magnetic foam option process. When t = 2 s, the foam starts to move; when t = 3 s, the foam comes into contact with oil droplet; and when t = 8 s, the foam starts to move with the oil droplet.

Figure 5

Dependence relationship between the maximum displacement x and various parameters, i.e. (a) the volume of the oil drop V_O, (b) the volume of the foam V_F, (c) the concentration of the magnetic particles C_P, and (d) the Young's contact angle ${\theta }_{\text{Y}}$.

Figure 6

Dependence relationship between the maximum acceleration in the first stage a₁ and various parameters, i.e. (a) the volume of the foam V_F, (b) the concentration of the magnetic particles C_P, and (c) the Young's contact angle ${\theta }_{\text{Y}}$.

Figure 7

Dependence relationship between the maximum acceleration in the second stage a₂ and various parameters, i.e. (a) the volume of the oil drop volume V_O, (b) the volume of the foam V_F, (c) the concentration of the magnetic particles C_P, and (d) the Young's contact angle ${\theta }_{\text{Y}}$.