Research On Rapid Detection Technology Of Weld Cracks On Drilling Riser Based On ACFM

This dissertation,based on “Thirteenth Five-year Plan " national science and technology major projects subject " Marine deep water oil and gas field development project ",The subproject is “deepwater riser-subsea wellhead whole-life integrity technology and engineering applications ".In view of the riser weld fast nondestructive testing technology needs,according to the riser weld inspection domestic or abroad standards based on ACFM detection technology.Research for the rapid detection of riser girth weld and heat affected zone.With the help of COMSOL finite element simulation software,A three-dimensional ACFM simulation model of riser girth weld and heat affected zone was established,Meanwhile,A sensor probe for rapid detection of riser girth weld and heat affected zone was designed.In the end,The rapid application testing system was developed.Finally,testing on the weld and the crack in the heataffected zone of the riser specimen in the laboratory,and realized the detection alarm for the crack required by the weld detection standard.The results show that the rapid detection system of riser weld based on ACFM can quickly detect the cracks in the girth weld,Under the condition of the first scan of the array detection probe,according to the detection results,it can provide the safety guidance for the riser.This paper focuses on the following contents:(1)Application of ACFM test scheme for marine riser girth weldIn view of the current riser weld fast nondestructive testing technology needs,Analysis of riser weld crack detection standards at domestic and abroad,And compared several nondestructive testing technology the advantages and disadvantages in riser detection,In the end,using the advantage of ACFM rapid detection technology,Design of ACFM applied to the riser girth weld detection scheme.(2)Modeling of marine riser girth weld simulation and design of array probeWith the help of COMSOL finite element simulation software,A three-dimensional simulation model of riser girth weld and heat affected zone was established,To analyze the magnetic field distortion around the crack,And the feasibility of this technology was verified according to the simulation results.Based on the characteristics of marine riser girth weld,combining with the numerical simulation analysis and test results,The purpose to optimized structure parameters,And the important parameters affecting the structure of the probe(sensor spacing arrangement,lifting height,etc)were studied,accoring to the studied result,Develop and design an array of rapid detection probes for Marine riser girth weld crack.(3)Development of marine riser girth weld crack detection systemCombine with the laboratory hardware system,improve the acquisition module,excitation module,stabilized power supply module and signal conditioning module.With the help of Lab VIEW programming software,And according to the structural characteristics of the risers girth weld crack detection probe array.Developed the rapid detection software of alternating current electromagnetic field for risers girth weld software.A complete quick detection system of the risers girth weld crack with the combination of the probe,case and software is constructed.(4)Test and result analysis of marine riser girth weld crack detection technologyUsing the riser circumferential weld crack defects detection system,Do the test and other riser crack defects experiment in the laboratory.For the purpose obtain array detection sensor and system of precision and sensitivity.And set a threshold alarm parameters,Finally,Realizes the depth of 1 mm crack in riser circumferential weld and heat affected zone,100% rapid detection and alarm.It can provide technical support to decision making for riser safety inspection and maintenance.