Production tubing

Abstract

The invention discloses a production tubing which comprises a sleeve, wherein the horizontal segment of the sleeve is provided with two floating couplings, wherein each floating coupling comprises a shell, a fixed sleeve, an upper sliding sleeve and a lower sliding sleeve; the upper sliding sleeve consists of a communication part and a shearing part; the shearing part is supported on the upper segment of the inner wall of the fixed sleeve by virtue of an upper shearing nail; the lower sliding sleeve is supported on the lower segment of the inner wall of the fixed sleeve by virtue of a lower shearing nail; the communication part is arranged in the lower sliding sleeve; the communication part is provided with a leakage flow hole; the upper end surface of the shearing part is provided with a steady flow groove; the groove width of the steady flow groove decreases progressively and upwards along the axial direction of the shearing part. The sleeve is additionally provided with multiple floating couplings, the sleeve is filled with air; since the sleeve positioned below the floating couplings is filled with air, after the sleeve enters a horizontal well section, gravity applied to the horizontal well wall is alleviated, friction between the sleeve and the well wall decreases, and the thrust pushing the sleeve to move forward is decreased, so that production tubing is beneficial to improvement on the cementing quality of the horizontal section and capable of favorably feeding the sleeve to a design 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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