Integral oil pipe processing method

Abstract

The invention discloses an integral oil pipe processing method. A centralizer adopting the method centralizes an oil pipe at the axis part of a mineshaft as far as possible so that the vibration displacement of the oil pipe can be reduced, and dynamic damage to the portion, close to a neutral point, of the oil pipe can be reduced; the elastic centralizer can be additionally arranged at a certain position above a packer so that bending stress generated by axial buckling can be reduced, and meanwhile, in the process of descending to the well bottom, the wall thickness phase of a centralizing strip is basically not worn; the centralizer is of a multiple-centralizing-sheet structure so that the centralizer can still stay within the elastic deformation range in the underground stress state, andtherefore, fatigue fracture cannot occur after long-term operation; the centralizer is made of an oil pipe material, so that the corrosion resistance of the centralizer is equivalent to that of the oil pipe; the centralizer with the structure adopts an integral structure, the defect that a conventional centralizer generates fatigue at the joints of welding and screws is overcome, in the later well workover process, casing milling and taking out of the oil pipe can be conveniently and safely implemented, and the centralizer is made of the scrapped oil pipe on a current oil field, so that the cost is reduced to the maximum extent.

Description

technical field [0001] The invention relates to the technical field of oil production engineering, in particular to an integral oil pipe centralizer and a processing method. Background technique [0002] Oilfield tubing production packers run into wells as deep as 6,500 meters, and the bottomhole temperature can be as high as 150°C-180°C. During the production process, the tubing above the packer buckles due to thermal expansion and contraction of the tubing, and the tubing is neutralized. The axial force near the point causes fluid-solid coupling vibration along with the production airflow, causing longitudinal and lateral displacement of the tubing near the neutralization point. As a result of this displacement, the tubing is prone to stress fatigue, especially in the range of 30cm above and below the tubing coupling , the tubing is affected by bending stress concentration and lateral collision inertia. Lateral collision inertia: when the tubing string undergoes lateral vi...

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Problems solved by technology

[0002] Oilfield tubing production packers run into wells as deep as 6,500 meters, and the bottomhole temperature can be as high as 150°C-180°C. During the production process, the tubing above the packer buckles due to thermal expansion and contraction of the tubing, and the tubing is neutralized. The axial force near the point causes fluid-solid coupling vibration along with the production airflow, causing longitudinal and lateral displacement of the tubing near the neutralization point. As a result of this displacement, the tubing is prone to stress fatigue, especially in the range of 30cm above and below the tubing coupling , the tubing is affected by bending stress concentration and lateral collision inertia. Lateral collision inertia: when the tubing string undergoes lateral vibration and collision, the coupling contacts the inner wall of the tubing, and the tubing has inertia along the displacement direction, resulting in the superimposition of bending stress near the coupling , causing the pipe body at both ends of the coupling to be subjected to a complex stress state, which may cause longitudinal and transverse cracks, and stress corrosion cracking in the disappearing zone of the pin buckle (the buckle position). Therefore, the centralizing strips of conventional elastic centralizers are connected by welding or screws. The joint with the screw is the main part where fatigue occurs. The centralizer is in a state of vibration and alternating stress for a long time, which is prone to fatigue failure or even fracture

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