| Aiming at the chromium chloride and acetic acid which were inexpensive, this issue synthesized a novel sol type organic chromium crosslinking agent in a simple synthesis process which changed the dispersion medium. The effect of temperature, PH and salinity valued for chromium sol stability crosslinkers were measured in the laboratory, the result showed that the chromium sol crosslinking agent was stable in alkaline environment of PH=8-10(PH=8-10was the PH of Daqing oilfield sewage). Furthermore, the stability of chromium sol crosslinking agent wes much better as the temperature rised. Salinity had no effect on the stability of the chromium sol crosslinking agent. Besides, this issue carried on the static evaluation of gel performance which was formed by chromium sol and HPAM. The results showed that the gel with higher strength and better stability could be obtained when n(Cr3+):n(Ac-) was1:2.5～3, concentration of Cr3+crosslinking agent was197-328mg/L and PH was7～9. The delayed effects could reach over4days. The prepared chromium sol in-situ crosslinking agent with the polymer still had a better performance in high salinity oilfield wastewater, which could adapt to high salinity formation water environment in Daqing. The chromium sol crosslinking agent was suitable for situ crosslinking deep reservoir, which could achieve the purposes of improving oil recovery. Finally, this assue studied the plugging efficiency of chromium sol/HPAM for cores with the indoor core analog devices flooding, and explored the best injection process. Used chromium sol and polymer injection separately, chromium sol and polymer injection broken plug injection, chromium sol and polymer injection after mixing to measure its blocking effect, respectively. The results showed that blocking effect of the three kinds of injection method in order enhanced, breakthrough pressure gradient was6.5MPa、9.8MPa、11.5MPa respectively. Anti-erosion ability could be better after the waterflood breakthrough. |
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