Screening study on microsphere used in profile control under the environment of microbial oil recovery

The performance of four microspheres samples (MS-1, MS-2, MS-3, and MS-4) were evaluated and optimized by indoor experiments. Firstly, the basic physical and chemical properties of the four kinds of microspheres were evaluated by analyzing the solid contents and the solubility in the water. Results showed that the content of the precipitated solids in MS-1 was the lowest in the four kinds of microsphere samples. The contents of the other three microspheres were similar in the value of solid content. Besides, the three microspheres of the solubility in the simulated formation water were excellent. Secondly, the expansion properties of three kinds of microspheres (MS-2, MS-3, and MS-4) were investigated. Results revealed that the expansion performance of MS-3 was greatly affected by microbial metabolism. However, the other two samples had excellent expansion performance under the condition of microbial flooding. Finally, the sealing performance of MS-2 and MS-4 was evaluated by physical simulation Block test. Results showed that compared with MS-2, MS-4 was more suitable for Block B.