Shaft bottom leakage-proof plugging device for well cementation

Abstract

The invention discloses a shaft bottom leakage-proof plugging device for well cementation, and belongs to petroleum drilling well cementation construction operation. The shaft bottom leakage-proof plugging device comprises an upper connector and a lower connector which are connected with each other. The center of the upper connector is provided with a first through hole, and the center of the lower connector is provided with a second through hole. The second through hole is a big-end-up stepped hole which is composed of a first cylindrical hole and a second cylindrical hole. The outer surface of the upper connector is provided with a plurality of by-pass holes and shear pin holes in the circumferential direction, wherein the shear pin holes are located below the by-pass holes. An inner cavity of the upper connector is provided with an annular packing groove which is located above the by-pass holes. The outer surface of the lower connector is connected with a rubber sleeve in a sleeved mode. The middle portion of the lower connector is provided with a plurality of check valves in the circumferential direction. A valve seat barrel is mounted in the first through hole and the second through hole. A third through hole in the center of the valve seat barrel is a big-end-up stepped hole which is composed of a third cylindrical hole and a fourth cylindrical hole. Balls are placed on step surfaces. Packing is mounted between the upper portion of the valve seat barrel and the packing groove. The valve seat barrel is connected with the upper connector through a plurality of shear pins. The valve seat barrel is provided with a plurality of fourth through holes communicated with the check valves. The shaft bottom leakage-proof plugging device can guarantee smooth proceeding of a cement job and cementing quality, and is simple in structure and convenient to install.

Description

technical field [0001] The invention relates to an oil well cementing construction operation, in particular to a well bottom leak-proof plugging device for well cementing. Background technique [0002] In cementing operations in petroleum, geological drilling and other fields, after drilling to the designed well depth, it is necessary to run the casing into the well, and inject cement from the inner cavity of the casing, so that the cement flows into the bottom of the well, and then flows out of the casing into the casing and Between the well walls, the continuously entering cement gradually rises until the entire space between the casing and the well wall is filled from bottom to top, so that the casing and the well wall are fixed together to strengthen the well wall. However, due to the presence of leaking layers in the bottom hole formation or improper operation when running the casing into the well, pressure surges are formed, resulting in bottom hole leakage. After the...

AI Technical Summary

Problems solved by technology

However, due to the presence of leaking layers in the bottom hole formation or improper operation when running the casing into the well, the pressure is excited and the bottom hole leakage occurs.

Cause cement to flow out from the leakage layer after entering the bottom of the well, resulting in cement not being able to fully flow between the casing and the well wall, affecting the quality of cementing or causing cementing failure

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