Structure Reliability Analysis For Special Drilling And Completion Equipment Of TLP Riser System

Specific to the need of oil drilling in South China Sea,this dissertation,which is Supported by the National Science and Technology Major Project “Research on the Design and Safty Technology of Tension Leg Platform Drilling and Completion Cluster Riser System(2016ZX05057011)”,Taking the riser system as the main object,studies TLP special operating equipment.The research covers statics analysis method of TLP riser system,structural analysis methods of the key equipment,reliability analysis methods,which acquires major progress,reliability assessment of riser system under 100-year return period was carried out,reliability design criteria of tapered stress joint was put forward.The research findings provide theoretical foundation and effective technical supports for the TLP riser system,the main research developments are as follows.(1)Rearch om reliability caculation method based on Kriging methodKriging model was established to simulate the relationgship between random variable and response by Latin Hypercube Sampling method,the model precision was checked by comparing the predicted response values calculated by Kriging and The practical simulation results,parameters of Kriging model were optimized,the optimizing model was created after multiple iterative,reliability Index was caculated by optimization algorithm.Finally,a reliability analysis method was put forwad by combining the Kriging model and Latin Hypercube Sampling method,and the reliability analysis process was determined.(2)Rearch on reliability of top tensioned risersMathematical analysis model of TLP top tensioned cluster risers was established,statics analysis of riser system under 100-year return period was developed,finite element analytical model was created to studied on the stress,bending moment and riesrs spacing ditribution along the depth direction.Combining finite analysis result and Kriging model,riser system reliability caculation models was estabished,inexplicit performance function between random variable and risers response was simulated by Kriging model.Finally,three methods of reliability analysis were comparatively studied.(3)Rearch on reliability of tapered stress jointGlobal-local analysis method and process were proposed,tapered stress joint local finite element analysis model was established,dangerous position in tapered stress joint was identified,research on stress distribution along length direction was carried out.Tapered stress joint reliability analysis model was built based on the result of finite element analysis considering current randomness,operating parameter randomness and structure size randomness,three methods of reliability analysis were comparatively studied.(4)Research on tapered stress joint reliability in the case of wellhead inclinationFinite element analysis model of tapered stress joint in the case of wellhead inclination was built,the influence of different wellhead angle was studied.Research on tapered stress joint reliability in the case of different wellhead angle was carried out.Tapered stress joint reliability analysis model was built by Kriging model considering different random factor,finally reliability design criteria of tapered stress joint was determined,which can supply reference to engineering.