Experimental Research On Relative Permeability Modifiers

Water flooding is an important method to achieve high and stable oil production. However, as time goes on, great amounts of injected water flows along high permeable zones, which results in earlier water breakthrough and reducing oil production. At present, water shut off using chemicals is a conventional technique, but it could block both the water and oil channels which decrease the oil production and influence the economic benefits. Relative permeability modifier (RPM) is a kind of selective water control agent, namely it can only decrease the relative permeability of water phase with little effect on oil phase. This dissertation discussed the development and application of RPM used for water shut off in oilfields. Two kinds of RPM (C-RPM and AM-RPM) were selected and evaluated through coreflooding experiments. Moreover, static and dynamic adsorption experiments were conducted to discuss some factors of the adsorption performance of C-RPM. The gel forming course of AM-RPM cross-linking system was analyzed through viscosity measurement, and the transition pressure was monitored to investigate the effect of AM-RPM concentration, polymer/crosslinker ratio and temperature on the gel forming course. In addition, the microstructure of AM-RPM colloidal dispersion gel system was also studied. Based on the experimental results and much field application experience, the suitability of RPM and general screening criteria of oil wells were established. The optimum conditions of using C-RPM and AM-RPM were obtained through experiments. And the results showed that these two kinds of RPM have good performances, such as good ablation resistance, water shut off ability with little effect on oil production. The field application of C-RPM in Gudong 905-3 well further confirmed that C-RPM has good performances. In this dissertation, RPM weak cross-linking system was also studied. The results showed that the system has a good injectivity, its residual resistance factor is 5~6 times of that of the RPM with the same concentration, and the dosage of polymer can be reduced greatly by using the RPM weak cross-linking system with the similar effect on water control, reducing the operation cost. As the RPM, RPM weak cross-linking system has a great effect on the relative permeability of water phase with little effect on oil phase, and has good selectivity.