Hot-melting sleeve heat stress automatic compensation device

Abstract

The invention provides a temperature-controlled hot-melting sleeve heat stress automatic compensation device. The temperature-controlled hot-melting sleeve heat stress automatic compensation device comprises a coupling, a pup joint, an outer cylinder, an inner cylinder, a sealing bushing, a connecting bushing, fastening nails, a locking bushing and a hot melt ring; the coupling is sequentially connected with the connecting bushing and the outer cylinder through the pup joint; the lower end of the sealing bushing is connected with the inner cylinder and then arranged in the outer cylinder, andthe sealing bushing and the outer cylinder are in axial sliding sealing fit; the hot melt ring is an open ring and is arranged at the junction of the sealing bushing and the inner cylinder, and the hot melt ring is simultaneously in limiting fit with an annular groove in the inner wall of the outer cylinder; and the locking bushing is matched with the fastening nails to be fixedly connected to thelower end of the outer cylinder, the inner wall of the locking bushing and the outer wall of the inner cylinder are in locking fit, a boss is arranged at the upper end of the locking bushing, and theboss and a groove pre-formed in the outer wall of the inner cylinder are in circumferential limiting fit. According to the temperature-controlled hot-melting sleeve heat stress automatic compensationdevice, the technical shortcomings and deficiencies of an existing compensator are effectively overcome, heat stress can be effectively released, expansion elongation of a sleeve is effectively compensated, and the sleeve is prevented from being damaged by heat.

Description

technical field [0001] The invention belongs to the casing thermal stress protection device in the technical field of oil and gas well completion. When the casing thermal stress exceeds a certain value, a locking switch is opened to release the casing thermal stress, protect the casing, and prolong the service life of the oil and gas well. Background technique [0002] Thermal stress casing damage is a very common phenomenon in oil and gas wells. If the thermal stress compensation device is not connected to the casing string, the casing will be damaged and ruptured. The average temperature of steam injection in thermal recovery wells is above 320°C. Under the action of continuous high temperature and axial tensile stress, fatigue cracks and compression deformation of the casing will occur, resulting in casing damage. The existing casing compensation devices for thermal recovery horizontal wells basically use shear nails to control the opening of the compensation device. The ...

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Problems solved by technology

[0002] Casing damage due to thermal stress in oil and gas wells is a very common phenomenon. If the thermal stress compensation device is not connected to the casing string, the casing will be damaged and ruptured.

The average temperature of steam injection in thermal recovery wells is above 320°C. Under the continuous high temperature and axial tensile stress, the casing will produce fatigue cracks and compression deformation, resulting in casing damage

The existing casing compensation devices for thermal recovery horizontal wells basically use shear nails to control the opening of the compensation device. The disadvantage is that when the thermal stress is greater than the shear force of the shear nails, the shear nails are cut off, and the compensator starts to work, realizing casing telescopic compensation

The biggest disadvantage of this compensator is the selection of the shear force of the shear nails, that is, the selection of the number of shear nails. If the selection is too small, the casing is easily cut in advance due to wear and resistance during the running process, resulting in the advance occupation of the compensation distance. , it cannot play a compensation role when injecting steam; if the shear force is too large, it is very easy to cause the shear nails to cut continuously when injecting steam, and still cannot play a compensation role

Moreover, the compensation ability is limited; the internal structure is complex, and the downhole application is prone to problems or even cannot work normally; the stress release is controlled by shear nails, which has poor impact resistance and is prone to failure

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