The invention relates to an offshore oilfield water
injection well online one-step-process acidification technology, which comprises following steps of (1) preparing one-step acid liquor, wherein the one-step acid liquor consists of following components by weight percent: 20 to 40 percent of industrial
acetic acid, 15 to 40 percent of industrial
hydrochloric acid, 3 to 15 percent of deposition inhibitor, 5 to 15 percent of discharging aiding agent, 3 to 15 percent of
corrosion inhibitor, 5 to 15 percent of antiswelling agent, 5 to 15 percent of iron
ion stabilizer and 2 to 10 percent of
hydrogen fluoride; (2) storing the acid liquor into an acid
storage tank of an injection
system, wherein the injection
system consists of the acid
storage tank, an acid resistant pump, a motor, a frequency converter, a flow sensor, a
pressure sensor, a computer, a
check valve, a three-way
pipe and an acid injection
pipe; (3) utilizing the acid resistant pump to pump the acid liquor into the water injection flow; (4) monitoring the variation of the pressure and the flow of the injected acid, and calculating
skin coefficients in real time; and (5) keeping the water injection after stopping the acid injection. Due to the adoption of the offshore oilfield water
injection well online one-step-process acidification technology, high efficiency, rapidness and large scale in plug removal of an offshore oilfield water
injection well can be realized, the water
injection pressure can be reduced, and the water injection quantity can be improved.