The water injection well of sandstone reservoir may succeed more than production well if taking acid fracturing treatment because reducing of effect closed pressure on acid etching fracture.

The axisymmertyical hyperbola function mathematical formulation of pressure fall-off curves is given by analysing the pattern of the generous pressure fall-off curves of the injection wells.

This injection well perforation parameter prediction theoretical method provides a new way to improve poor formation's water absorbing capability and mitigate over fracture pressure injection.