Open well anchoring flushable releasing tool and application of open well anchoring flushable releasing tool in well completion construction

The invention particularly relates to a barefoot well completing tool and a well completion construction technology. An open well anchoring flushable releasing tool is formed by connecting an upper joint, a torque head, a ball, an internal sliding sleeve, a working barrel, an internal washing pipe, a cutting sleeve, a screen pipe, a dowel, clamping teeth, a sliding ring, a shear pin and a lower sliding ring. During construction, the screen pipe and the internal washing pipe are put into a well together. After the washing construction, the pressure ball is thrown into the well so as to to anchor and hang the releasing tool under the well. Pressure is continuously exerted. The upper joint is lifted upwards so as to pull out the upper joint, the ball and the internal washing pipe, and the screen pipe is left under the well. According to the invention, the cutting sleeve is unique in design, so that a small tool can be hung in a large pitshaft, for example, a 90 mm tool can be riveted in a 130 mm borehole. In addition, the screen pipe and the internal washing pipe are put into the well together for flushing operation, so that unsmooth construction, frequent reworking and even well rejection due to a fact that flushing, which causes well expansion, is performed before the screen pipe is put into the well, are avoided .