Study of Thickening Combined Gel for In-depth Water Shut off in Offshore Oilfields
In view of the limited working space and characteristics of low gelling strength and weak plugging ability of traditional online injection plugging agent system in offshore oil reservoirs,a composite gel system composed of AMPS temperature resistant and salt resistant lotion polymer,polyethyleneimine(PEI)crosslinker and inorganic nano reinforcer was developed.Through gelling experiments,the effects of component mass fraction,temperature and salinity on the gelling performance of the composite gel system were studied,the reasonable formula was optimized,and the injection and migration performance,thermal stability and selective plugging performance were evaluated.The results indicated that as the mass fraction of polymer,crosslinking agent,and inorganic nano-reinforcing agent increased,the gelation time decreased and the gelation strength increased.Compared with single gel system,composite gel system had shorter gel forming time and stronger strength.The results based on core injection and migration performance showed that the viscosity of the compound gel system to be formed was low,and it could achieve injection and deep migration in porous media to achieve the purpose of deep plugging.At the simulated reservoir temperature of 80℃,the dehydration rate of composite gel system was still lower than 10%after 90 d aging.This system had good selective sealing performance for formations with different permeability.
Offshore reservoirsIn-depth water shutoffcombined gelBulk gelationPerformance evaluation
万方数据
维普
