A New Multichelating Acid System for High-Temperature Sandstone Reservoirs

Table 1

Comparison of corrosion rate of multichelating acid and conventional mud acid.

	9% HCl + 1.5% HF	5% H3PO4 + 4% SAV-1 + 1% SAV-2 + 1.5% NH4F
Before corrosion
After corrosion
Corrosion rate (g/m^2·h)	586.75	53.92
Conditions	Temperature: 120°C; time: 4 h