New Online Shunt Acidification for Water Injection Increasing Technology and Its Application in Huanjiang Oilfield

Table 1

The chelating performance of chelate acid COA-1S and other acids.

Sample	Scale inhibition rate to BaSO4 (%)				Inhibition rate (%)
	pH = 3	pH = 5	pH = 6	pH = 7	CaF2	Fe(OH)3	Fluoroaluminate
Mud acid	0.73	0.76	0.79	0.68	—	—	—
Multihydrogen acid	3.41	5.58	7.39	9.38	60.72	36.26	31.45
COA-1S	15.62	64.37	78.69	89.37	98.81	96.62	96.72