Microbubbles generation by an orifice spraying method in a water-gas dispersion flooding system for enhanced oil recovery

In China, many oilfields with low permeability and heterogeneity have entered the secondary oil recovery stage, in which more oil displacement agents for expanding sweep volume has become a key technology. A water-gas dispersion flooding system is reasonably proposed to change the seepage resistance and adjust the mobility ratio. In this FOR technique, the generation of micron-sized bubbles in the low-permeability reservoir is of considerable interest. In this study, a visual device by using an orifice spraying method was designed to simulate reservoir conditions with high temperature and high pressure, and efficiently to produce more microbubbles. Based on the orifice spraying method, the morphological characteristics of microbubbles generated by different orifice plate materials were compared, which provided the choice of the microbubbles generation by the orifice spraying method for laboratory experiments. Besides, the influence of different factors on the quantity and size of microbubbles produced by a single orifice plate was presented in detail. The experimental results showed that the diameter of the microbubbles generated by the orifice spraying method under a hypothetic reservoir condition was about 10-100 mu m. These visual experimental devices were practically designed to meet the demand of the micron-level pores and throats to enhance oil recovery in low-permeability reservoirs. This investigation of microbubbles generation provided the basic research means for further preparation of a water-gas dispersion flooding system.