Abstract: Eight kinds of scale inhibitors have been screened out and the optimal dosage has been decided on the base of perpendicular experimental results. The mixed samples with the optimal and the worst mixture ratio have been measured by the laser particle device under the formation temperature (60 ℃) and the normal temperature (20 ℃) . Results show that solid concentration and particles diameters have changed. The damage of the cores caused by the two kinds of mixed samples has been evaluated contrastively under normal and formation temperature when inhibitors existing or without inhibitor. The damaged degree of cores caused by the optimal mixture ratio of the mixed sample is slighter than by the worst mixture ratio. As to the mixed samples with the same mixture ratio , the damage to cores under the
formation temperature is less serious than the normal temperature when adding inhibitor ; the damage to cores brought by the two kinds of mixed samples after adding inhibitors is less than ones without inhibitors.

Key words: mixed injection, scaling, temperature influence, scale inhibitor, reservoir damage