Abstract: The non-active nitric powder is a new material for acidizing which exhibits non-active in normal state but can decompose strong oxide HNO3after activation. In order to solve some problems that the activation underground is hard to control and the power has low efficiency in the acidizing treatment by non-
active nitric, an activator A has been selected successfully, opti-mized its applying concentration and acquired a new acidizing fluid formula system. In this system, a pre-activating technolo-gy in the ground has been adopted which can reach higher core corrosion rate and permeability, low corrosion rate to metal so that the purpose for deep acidizing can be achieved. Results ap-
plied in the field have shown that the effect of stimulation is no-table after acidizing treatment by the formula, and it is suitable for acidizing to sandstone reservoirs which permeability are low to extreme low and strong sensitive.

Key words: non-active nitric acid power, acidizing fluid, plug removal, sandstone reservoir, optimization design