摘要：Low-permeability reservoirs have the charac- teristics of low permeability and strong heterogene-ity. The water flooding development process is prone to induce plane fingering and form advantageous seepage channels, which in turn leads to a decreasein water flooding spread and low water flooding ef-ficiency. In this paper, low-permeability sandstone crushed samples were selected and prepared into five groups of high-and low-permeability cores. Then. the optimization experiments of indoor dual-tube parallel injection of nanometer microspheres were conducted. Furthermore, the expansion time and mass concentration of the nano-microsphere solution were optimized. The experimental results show that the effect of the nano-microsphere solution for flood- ing and diversion gradually increases with the exten- sion of the expansion time, but when it exceeds 100 h, the effect of flooding and diversion is basicallynegligible. The final water flooding recovery factor increases first and then decreases as the mass con- centration of the injected nanosphere solution in- creases. The highest water flooding recovery factor is 44.2%, and the corresponding injected mass con- centration is 2 000 mg.L.l. In the development pro- cess of nano-microsphere control and flooding in low-permeability reservoirs, timeliness should be considered in the process of water absorption and ex-pansion. That is, while ensuring the recovery factor, it is also necessary to minimize the time of water ab- sorption and expansion. The optimal process of the mass concentration of the nano-microsphere solution should fully consider the liquid-carrying and trans- porting capacity in the porous medium.
关键词：Low-permeability reservoirs;water flooding development;nanometer microspheres;mass concentration;expansion time
