Efficient retarded acidification working fluid and preparation method thereof

The invention discloses an efficient retarded acidification working fluid and a preparation method thereof. Every 100 parts of the efficient retarded acidification working fluid comprises the following components in parts by mass: 10-20 parts of ammonium salt, 5-20 parts of organic phosphonic acid, 5-20 parts of hydrochloric acid, 1-6 parts of a corrosion inhibitor, 0.5-2 parts of a clay stabilizer and 0.5-2 parts of an iron ion stabilizer, with the balance being water. The preparation method of the efficient retarded acidification working fluid comprises the following steps: adding the water into the ammonium salt at normal temperature and normal pressure, and carrying out stirring and dissolving to obtain an ammonium salt solution; adding the hydrochloric acid and the organic phosphonic acid into the ammonium salt solution, and carrying out uniform stirring and mixing to obtain a retarded acid solution; and sequentially adding the corrosion inhibitor, the clay stabilizer and the iron ion stabilizer into the retarded acid solution, and carrying out uniform stirring and mixing to obtain a finished product. The efficient retarded acidification working fluid has a good corrosion effect on stratum rocks and can improve the permeability of rock cores; and the efficient retarded acidification working fluid has good slow-release property, can act on stratum rocks for a longer time, realizes deep plug removal, and is beneficial to yield increase of petroleum and natural gas reservoirs.