Silicate scale clearing agent for ternary combination flooding extraction well

The invention discloses a silicate scale clearing agent for a ternary combination flooding extraction well. The silicate scale clearing agent consists of prepad fluid and scale clearing main agent. The prepad fluid consists of 6% of additive (SYQ-II) and the balance of water. The additive (SYQ-II) consists of sodium dodecyl benzene sulfonate (ABS), nonyl phenol polyethenoxy ether (OP10) and ethylene glycol monobutyl ether with the ratio of 3:1:2. The scale clearing main agent consists of 12% of hydrochloric acid, 10% of hydrofluoric acid, 2% of glacial acetic acid, 0.2% of citric acid, 0.5% indoor-synthesized imidazoline type corrosion inhibitor (YC-II) and the balance of water. The scale clearing agent achieves a silicate scale clearing rate up to 80%, and can effectively clear silicate scale at an oil well pump cylinder, a rod pipe and other positions and prolong the pump examination period of the extraction well.