Safety evaluation method for well head tubing head spool with crack defect

Abstract

The invention belongs to the technical field of safety evaluation of well head device structural members with the defects, and especially relates to a safety evaluation method for a well head tubing head spool with a crack defect. The method improves the matching degree of a stress distribution finite element simulation calculation value of the tubing head spool with the actual member stress distribution through the impact on the stress distribution of the tubing head spool from constraint conditions generated by different assembly modes, and can achieve the more accurate safety evaluation ofthe of the tubing head spool with the crack defect. The method comprises the steps: determining the physical dimension of the tubing head spool, and calculating and obtaining a representative crack size; determining the parameters of a tubing head material; building a tubing head spool finite element model; calculating a stress strength factor KI of a crack body of the tubing head spool; calculating a critical stress strength factor KIC of the material and a material crack toughness KC for evaluation; comparing the stress strength factor KI with the material crack toughness KC for evaluation,and determining the safety performances of the crack body.

Description

technical field [0001] The invention belongs to the technical field of safety evaluation of structural components of wellhead devices with defects, and in particular relates to a method for safety evaluation of wellhead tubing head crosses with crack defects. Background technique [0002] As one of the core components in the oil production system, the wellhead tubing head spool plays a vital role in the safe production of oil wells. During use, the inner and outer walls of the wellhead tubing head spool will be affected by factors such as corrosion, particle wear, medium erosion collision, abnormal pressure, etc., and defects such as cracks and thinning of the wall thickness will occur, resulting in the safety of the device operation. Hidden danger. If the over-standard crack defects inside and outside the casing of the wellhead tubing head spool exist for a long time and expand day by day, it will inevitably cause the casing to crack suddenly in a certain working state, or...

AI Technical Summary

Problems solved by technology

However, the inventor found after research that the above-mentioned existing evaluation methods for pressure vessels with defects are only applicable to pressure vessels with defects of standard sizes, and cannot perform safety checks and evaluations on pressure-bearing structural parts with complex structures; Defects such as lack of experience, insufficient accuracy and reliability of judgment

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