Abstract: Basic requirements of acid fluid for acidizing treatment were analyzed in this paper based on the Badaowan formation with low-permeability in Yanqi Basin. a lot of experimental evaluations were made according to the oil and gas industry standard of China, and the type and concentration of the acid liquid
were determine. A compound-acid with good retarded property,low damage for the formation and excellent stimulation effect was given though choosing corrosion inhibitor, iron-control agent, clay stabilizer and cleanup additive in laboratory. A new acidizing technique was introduced and improved. The com-
pound acid fluid and technology was successfully practiced 9 wells, and the great economic and social benefit was got.

Key words: Yanqi bansin, Badaowan formation, sand-stone reservoir, compound-acid, acidizing treatment