The invention discloses a shaft bottom leakage-proof plugging
system and a method for cementing a well with the
system, and belongs to
petroleum drilling and well cementation construction operations. The
system is composed of an upper connector, a lower connector, a casing
pipe and a casing shoe, the upper connector is connected with the lower connector, and the casing
pipe and the
casting shoe are arranged on the upper connector and the lower connector respectively. In the well
cementation process, when the system is arranged down to the well, after the casing
pipe is down to a preset depth, a ball is put in, the ball reaches the second step face of a
valve seat barrel, pressurization is carried out in the
valve seat barrel, a rubber sleeve expands due to pressure and extrudes a well wall, fixed sealing and isolation is achieved, then pressurization is carried out further, a
shear pin is shorn, the pressure pushes the
valve seat barrel to move to the first step face, a bypass hole of the upper connector is exposed out,
cement paste is poured in through the upper end of the casing pipe, flows out of the bypass hole, and is filled into the space between the well wall and the casing pipe, the normal well cementation operation is carried out, the poured-incement paste in the well
cementation process can be prevented from being leaked through a well bottom leakage layer, the smooth well cementation operation is guaranteed, well cementation quality is guaranteed, and the system is simple in structure and convenient to
mount.