Long-acting clay stabilizer and preparation method thereof

The invention discloses a long-acting clay stabilizer and a preparation method thereof and belongs to the technical field of oil field chemicals. The long-acting clay stabilizer is prepared from components in percentage by mass as follows: 0.5%-1.5% of a dimethyl diallyl ammonium chloride-acrylamide copolymer, 1%-2% of ammonium chloride and the balance of water. The components of the long-acting clay stabilizer cooperate with one another and have a synergistic effect, the water-sensitive and water-locking damage to reservoirs is reduced greatly, the reservoirs are protected from invading damage by external working solutions, requirements for reservoir protection of low porosity and low-permeability reservoirs and strong water-sensitive reservoirs in a construction operation process are met, and the problems of clay swelling, migration and blockage in the reservoirs due to invasion of the incompatible external working solutions into the reservoirs are solved; the long-acting clay stabilizer has the advantages