Casing pipe

Abstract

The invention provides a casing pipe. The casing pipe comprises a casing pipe body and a coupling connected with the casing pipe body, the radial size between the outer side wall of the coupling and the hole wall of a second through hole is larger than a preset value, at least one flow guide groove is formed in the outer side wall of the coupling, the extending direction of the flow guide groove is consistent with the extending direction of the coupling, the radial depth of the flow guide groove is smaller than the radial size between the outer side wall of the coupling and the hole wall of the second through hole, and the end, facing the well bottom, of the coupling is provided with a turbulent flow preventing part which is used for reducing turbulent flow and vortex formed by fluid at the joint of the coupling and the casing pipe. According to the casing pipe, under the condition that the strength requirement of the coupling is met, the shearing rate and the shearing stress distribution rule of a flow field area at the narrow edge near the coupling are improved by arranging the flow guide groove and the turbulent flow preventing part on the outer side wall of the coupling, the well cementation displacement efficiency is improved, false filter cakes on the well wall can be better removed, and the cementation quality of a second interface is improved.

Description

technical field [0001] The invention relates to the technical field of oil and gas well cementing, in particular to a casing. Background technique [0002] Cementing quality is particularly important for sealing oil and gas water layers, preventing annular oil and gas water channeling, prolonging the service life of oil and gas wells and later acid fracturing production, and the cementing quality of the target interval is the most influential and most critical of all well barriers Especially for wells with active oil, gas and water, and thin interlayers that have high requirements for interlayer isolation, when cementing the target layer in highly deviated wells and horizontal wells, due to the large inclination of the well, the casing The eccentricity of the pipe is serious, and the position of the coupling is prone to "welding" phenomenon, resulting in an extremely unbalanced distribution of shear rate and shear stress on the wide and narrow sides of the eccentric annular ...

AI Technical Summary

Problems solved by technology

[0004] However, the existing centralizers are prone to misalignment and damage during running in highly deviated well sections and horizontal well sections. Therefore, the casing centering condition is poor, and the wall shear stress distribution of spacer fluid and cement slurry at the wide and narrow sides is extremely uneven. , and during the cementing displacement process, turbulence and vortices will be formed in the flow field area behind the coupling, which is not conducive to the displacement of drilling fluid and the removal of virtual mud cake on the well wall, and it is difficult to ensure the cementation quality of the second interface

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