Anti-pollution protecting method and device for sandwiched perforating gun

The present invention relates to the anti-pollution protecting method and device for sandwiched perforating gun in oil and gas well. The sandwiched perforating gun has sealing structure at its two ends, and the explosive fuse of perforating gun is isolated from that of sandwiched gun. The sealing structure between the perforating gun and the sandwiched gun consists of joint and blast propagator inside the cavity of the joint. The two ends of the blast propagator are connected to explosive fuses of perforating gun and the sandwiched gun separately. After the perforating gun is made to explode,the liquid is impossible to enter to the cavity of the sandwiched gun, and this can prevent environmental pollution caused by repeated use of the sandwiched gun. In addition, in case of breakdown of blast propagation, no liquid enters to the cavity of the sandwiched gun, and this makes it possible for the perforating gun and the sandwiched gun to be re-used.