Optimization of fractured shale oil energized imbibition huff and puff process by on-line nuclear magnetic resonance monitoring method
As currently important technology for shale oil reservoir development,energized imbibition oil recovery method can improve crude oil recovery efficiency by replenishing formation energy and replacing reservoir crude oil.Reasonable design of energy-enabled imbibition process parameters can develop shale reservoirs more efficiently.In this paper,four rounds of huff and puff experiments are conducted,on-line nuclear magnetic resonance technology is used to analyze the microscopic migration characteristics of nano-scale crude oil,and thus,the reasonable soaking time,empowerment timing,huff and puff rounds and other empowerment imbibition process parameters of fractured shale oil reservoirs are optimized.The experimental results show that the first soaking time can be controlled within 12～15 days,and the soaking time should be reduced accordingly with the increase of throughput rounds.After 3 rounds of huff and puff,the effect on improving oil recovery is not obvious with evidently effective rounds.After the pressure drops to 70%of the original formation pressure,the production effect by continuous pressure reduction is poor,which requires to replenish the formation in time to maintain the efficient development of shale oil wells.Different liquid injection volume has greater effect on the amount of produced oil when energized.If the injection volume is too low,the energy supplement is not sufficient,resulting in worse recovery effect.However,due to the extremely low permeability of the reservoir,the radius of the supplementary energy is limited,and the amount of injected supplementary fluid cannot be increased indefinitely.Reaching about 0.4 PV of the induced fracture control volume is generally acceptable.This research offers technological foundation for parameters optimization of shale oil reservoir energized inbibition technology.
shale oilmicro-fractureonline nuclear magnetic resonance technologysoaking timeenergized imbibitiontiming of huff-n-puffprocess optimization
万方数据
维普
