The invention provides a deep blockage removal and injection increase method for a water
injection well of a medium-and-high-permeability sandstone reservoir. The method mainly solves the problems of
oil pollution, deep blockage removal of a
ground layer and the like of a
sewage injection well, which can not be solved in the existing conventional acidification method. In the method, the
slug type injection technology of "washing-clearing-blockage removing-stabilizing" is adopted; and the injection increase effect can be improved and the injection increase
effective date can be prolonged. The method comprises the following steps: during construction, firstly, the well is backwashed at high displacement, and impurities near a well bore and a bore hole are washed; secondly, organic blockages near an oil layer are washed; then, organic and inorganic blockages in the areas near the well and the deep part of the oil layer are removed in the mode of multistage injection and multiple acid liquid systems, so that the seepage capability is improved; and finally, stabilizing treatment is adopted for prolonging the injection increase
effective date. Through the adoption of the
slug type injection technology, blockage damage is removed in batches, and substrate treatment, scale prevention treatment and scale inhibition treatment are performed so that the injection increase effect is improved, the injection increase
effective date is prolonged and a better blockage removal effect is achieved.