Experimental study of the influencing factors and mechanisms of the pressure-reduction and augmented injection effect by nanoparticles in ultra-low permeability reservoirs

Nanoparticles(NPs)have gained significant attention as a functional material due to their ability to effectively enhance pressure reduction in injection processes in ultra-low permeability reservoirs.NPs are typically studied in controlled laboratory conditions,and their behavior in real-world,complex environments such as ultra-low permeability reservoirs,is not well understood due to the limited scope of their applications.This study investigates the efficacy and underlying mechanisms of NPs in decreasing injection pressure under various injection conditions(25—85℃,10—25 MPa).The results reveal that under optimal injection conditions,NPs effectively reduce injection pressure by a maximum of 22.77%in core experiment.The pressure reduction rate is found to be positively correlated with oil saturation and permeability,and negatively correlated with temperature and salinity.Furthermore,particle image velocimetry(PIV)experiments(25℃,atmospheric pressure)indicate that the pressure reduction is achieved by NPs through the reduction of wall shear resistance and wettability change.This work has important implications for the design of water injection strategies in ultra-low permeability reservoirs.

Augmented Effect of Composite Salvia Miltiorrhiza Injectionon Radiosensitivity of Leukemia Cells

Objective: To explore the effect of Composite Salviae miltiorrhizae Injection (CSMI) on radiosensitivity of leukemia cells. Methods:Semisolid agar culture and flow cytometry assay were performed for studying the change in radiosensitivity of HL60 cell line and fresh human leukemia cells after exposing to CSMI.Results: The D0 (the inverse of the slope of the survival curve) and SF2 (survival fraction at 2 Gy) of HL60 cell line were decreased from 1. 53, 0. 34 to 0. 93, 0. 12, respectively and apopotosis rates after radiation were raised significantly by CSMI. Furthermore, the concentration of CSMI and the time of mixed culture with CSMI before irradiation had positive relation to the effects mentioned above. Compared with control group, CSMI could increase the radiation-induced apoptosis of fresh leukemia cells (5. 89 ± 2. 91 vs 12. 05 ± 3. 06). Conclusion: CSMI could obviously enhance the radiosensitivity of leukemia cells.Original article on CJIM(Chin) 1998; 18(5): 279