Backflow prevention device

Abstract

The invention provides an anti-backflow device, which belongs to the technical field of well cementation and comprises an outer shell and a backflow one-way valve assembly. The backflow one-way valve assembly comprises a valve body, a valve element, an elastic piece and a positioning piece, the valve body is located in the outer shell, a backflow cavity is formed in the valve body, a first opening is formed in one end of the valve body, a first end plate is arranged at the other end of the valve body, a backflow hole and an insertion hole are formed in the first end plate, and the backflow hole is communicated with the backflow cavity; the first end of the valve element is used for communicating or blocking the backflow cavity and the first opening, a first clamping groove is formed in the position, close to the second end of the valve element, of the outer side wall of the valve element, the first end plate is provided with a second clamping groove, the second clamping groove and the first clamping groove are oppositely arranged in the moving direction of the valve element, and the elastic piece is compressed between the valve element and the first end plate. The compression direction of the elastic piece is the same as the moving direction of the valve element, and the elastic piece is used for clamping the positioning piece between the first clamping groove and the second clamping groove. The construction steps can be simplified, and the construction time is saved.

Description

technical field [0001] The disclosure belongs to the technical field of well cementing, and in particular relates to an anti-backflow device. Background technique [0002] In the process of oil and gas development, after the drilling reaches the target layer, the liner operation will be carried out, and the well cementing operation will be carried out through the liner, which can reduce the subsequent construction difficulty and construction cost. [0003] In the related technology, after the tail pipe is lowered to a designated position, the pressure is suppressed by throwing a ball, so as to realize the mounting of the hanger, so as to complete the fixing of the tail pipe on the casing. After the liner is fixed, cement slurry is pumped to the liner through the surface cementing equipment. In order to prevent the cement slurry from flowing back into the liner and causing plugging accidents in the liner, floating hoops are usually arranged at the end of the liner. [0004] ...

AI Technical Summary

Problems solved by technology

[0004] However, since the floating hoop acts like a one-way valve, it only allows fluid to flow out of the tailpipe, but not into the tailpipe. Therefore, during the process of lowering the tailpipe, the inside of the tailpipe is hollow, and wellhead grouting is required to To balance the pressure difference between the inside and outside of the tailpipe, the construction steps are cumbersome and require a long construction time

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