Through the combination of imbibition and displacement,the impact of the combined action of imbibition and displacement on reservoir pressure and fluid flow during the soaking process after reverse hydraulic fracturing assisted oil displacement in low-permeability reservoirs was explored.A semi-analytical mathematical model for productivity prediction of reverse hydraulic fracturing assisted oil displacement is established,considering interlayer heterogeneity.An analysis was conducted on the changes in the flow field before and after soaking.Parametric studies are conducted to reveal the effects of permeability ratio, total injection volume,injection rate and soaking time on the pressure swept range,saturation swept range and cumulative oil production of each layer after soaking.The research results indicate that soaking well after hydraulic fracturing assisted oil displacement can enhance the energy enhancement effect of reverse hydraulic fracturing assisted oil displacement,further expand the affected area,and thus utilize more geological reserves.To achieve efficient development through hydraulic fracturing assisted oil displacement,it is recommended to consider layered mining when the permeability ratio is greater than 25.Meanwhile,the soaking time should be controlled within 10~15 days,with a properly reduced injection rate and increased total injection volume.

Transition metal sulfides are known for their high conductivity and theoretical lithium storage capacity,making them promising materials for phase change lithium storage.However,their cycling stability needs improvement.A simple electrostatic spinning method was used to prepare composites with in situ growth of cobalt-based zeolite imidazolite backbones(Co-ZIFs) on electrostatically spun fibers,and the stabilized structure of microzonated ZIFs was exploited to achieve spatially confined domains of metal particles in an N_? heat treatment. Cobalt sulfide/carbon fiber composites (CoS/CFs) were then synthesized through a sulfidation reaction.X-ray diffraction (XRD) and Raman spectroscopy confirmed the uniform distribution of CoS particles on the carbon nanofibers.The optimized composite showed excellent lithium storage performance,maintaining a specific capacity of 584.5 mA·h/g after 250 cycles at a current density of 1 A/g.This demonstrates outstanding cycling stability and suggests promising applications in lithium storage.