Production tubing

Abstract

The invention discloses an oil production string, which includes a casing, and two floating couplings are arranged on the horizontal section of the casing. The floating coupling includes a casing, a fixed sleeve, an upper sliding sleeve and a lower sliding sleeve, and the upper sliding sleeve It is composed of a connecting part and a shearing part. The shearing part is supported on the upper part of the inner wall of the fixed sleeve through the upper shear nail, and the lower sleeve is supported on the lower part of the inner wall of the fixed sleeve through the lower shear nail. There is a discharge hole on the upper part of the shearing part; a steady flow groove is opened on the upper end of the shearing part, and the groove width of the steady flow groove decreases along the axial direction of the shearing part. By adding multiple floating collars on the casing, the casing is kept full of air. Since the casing below the floating collar is filled with air, after the casing enters the horizontal well section, the gravity acting on the horizontal well wall is reduced, and the casing The friction between the pipe and the well wall decreases accordingly, and the thrust to push the casing forward also decreases, which helps to improve the cementing quality of the horizontal section and facilitates running the casing to the designed position.

Description

technical field [0001] The invention relates to the field of petroleum exploitation, in particular to an oil production string. Background technique [0002] The completion of extended-reach horizontal wells is characterized by high inclination, long open hole, and long section of stabilizing well. In the case of high inclination angle, the casing string is close to the lower well wall. After entering the horizontal section, the casing string will be completely attached On the lower well wall, the contact section between the casing string and the formation is very long at this time, and the casing string is loaded on the horizontal section of the well wall. The friction resistance of the formation to the casing string is quite large, and it cannot even go down to the bottom of the well by its own weight. , It needs to be pressurized to slide down, and it is easy to cause the casing string to buckle, and it may even cause the casing string to be stuck in the curved section of...

AI Technical Summary

Problems solved by technology

[0002] The completion of extended-reach horizontal wells is characterized by high inclination, long open hole, and long section of stabilizing well. In the case of high inclination angle, the casing string is close to the lower well wall. After entering the horizontal section, the casing string will be completely attached On the lower well wall, the contact section between the casing string and the formation is very long at this time, and the casing string is loaded on the horizontal section of the well wall. The friction resistance of the formation to the casing string is quite large, and it cannot even go down to the bottom of the well by its own weight. , it needs to be pressurized to slide down, and it is easy to cause the casing string to buckle, and it may even cause the casing string to be stuck in the curved section of the wellbore due to the high rigidity of the casing and cannot be run in

Due to the high frictional resistance of the casing string, the casing string often cannot go down to the predetermined position smoothly, delaying the construction progress, affecting the subsequent oil recovery effect, and even causing serious consequences of wellbore scrapping

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