Packer stepwise multistage fracturing string and method of use

One kind packer stepwise multistage fracturing string and method of use, fracturing string comprising a plurality of packers and fracturing sleeve, each corresponding to a packer sleeve fracturing, matching pairs use packer packer pressure transmission passage through the pressure transmission pipe connected to the pressure transmission sleeve hole of fracturing. Usage: 1) fracturing string assembly; 2) fracturing string will go down, so that the position of the sliding sleeve bleed passage with the reservoir sections each corresponding to one of the fracturing string; 3) start running key. inner cylindrical sleeve open, exposing pressure transmission hole packer packer; seal pressure test;. 4) within the rail pressure continues to open the cylinder sleeve is exposed sleeve bleed passage, fracturing embodiment; 5) press from the setting-up, fracturing the sequence, repeating steps 3), 4), the sleeve fracturing the fracturing string progressively open all levels, each one open, the corresponding orders packer packer and inspection seal, and fracturing the corresponding orders until the completion of the final fracturing level.