Apparatus for de-clamping loose formation well pipe

The invention discloses a jam releasing device for well pipes in unconsolidated formation; the jam releasing device is composed of a hollow cylindrical impact bar and a cylindrical inside band fixedly connected in the middle part of the impact bar; the axle line of the inside band is parallel to that of the impact bar; the longitudinal section of the inside band is trapezoidal; an inclined wedge surface which has a 10 to 15 degree included angle with the axle line of the impact bar is formed at the lower part of the impact bar; a duck-bill hole is formed at the bottom of the impact bar; a plurality of spiracles facing the side of the inside band is arranged in the middle of the impact bar; the high-pressure current ejected from the duck-bill hole at the bottom of the impact bar can wash matters jammed at and adhered to the outer wall of the well pipe back to the ground; the axis of the spiracles facing one side of the inside band in the middle of the impact bar has different included angles with the horizonta