Study On Strength Check And Test Method Of Subsea Vertical Christmas Tree

In this paper,through the research of applicable vertical standards and data of subsea vertical christmas tree,the design and requirements of subsea vertical christmas tree production are studied.The content includes the selection,design method,safety configuration and basic design elements of subsea vertical christmas tree.Ontology design essentials,valve design,valve group and driver design criteria and design points.This part helps to complete the overall structure design of subsea vertical christmas tree better and faster,and ensures that the subsea vertical christmas tree structure is reasonable and complete.Based on the comparison of the commonly used strength theory and the analysis of the applicability of the standard method for verifying the strength of subsea vertical christmas tree,it is established that the strength criterion for the verification of the strength of the subsea vertical christmas tree is Von Mises deformation energy theory.Based on the von Mises yield strength criterion,the parameters such as the wall thickness of the subsea vertical christmas tree and the welding coefficient were introduced to derive the wall thickness calculation formula and the strength verification formula for the subsea vertical christmas tree,which was designed for the subsea vertical christmas tree structure.The verification calculation provides the basis and reference.Taking an subsea vertical christmas tree body assembly module as an example,the modeling of the subsea vertical christmas tree is carried out and ANSYS finite element analysis is performed.This thesis uses the simplified modeling and overall modeling to verify the strength of the subsea vertical christmas tree's ontology.It is found that the stress concentration exists at the inner wall of the end caps of the body of the subsea vertical christmas tree body wellbore.It is not possible to directly use the traditional strength theory verification formula to check the strength of the subsea vertical christmas tree body wellbore.The location of stress concentration in the wellbore of the subsea tree is located at the weakest channel of the tree wellbore and at the inner wall of the two end caps.In the design and verification of the whole shaft and head of the wellbore,special attention should be paid to the effect of axial stress on the strength,and the wellbore body should pay special attention to radial stress.The verification method of subsea vertical christmas tree test was studied,and the general requirements of the performance verification test and the test method of pressure-temperature cycle experiment of subsea tree were discussed.The component range,pressure test range and test method of subsea vertical christmas tree production acceptance test are discussed.The test contents of the extended X-ray acceptance test,system integrity test and engineering environmental test of the X-tree plant were described.Based on the study of design standards,we propose operability verification methods and verification criteria.A systematic explanation of the main test validation content and test method flow of subsea vertical christmas tree production was carried out.It has promoted the research of test verification methods for domestic subsea vertical christmas tree.In summary,this paper presents the structural design requirements,ontology verification calculations,ontology strength finite element analysis,and subsea vertical christmas tree testing involved in the study of the strength verification and test methods for subsea vertical christmas tree body strength.The verification methods and other aspects have been studied.This content can provide certain technical theoretical support for the design,verification and testing of subsea vertical christmas tree,and will help promote the localization of subsea vertical christmas trees.