Research Of Structure Design And Strength Of Ultra-deep Water Drilling Vessel

Drilling vessel is one of the most advanced offshore oil drilling equipment in the world.With the decrease of onshore resources development in China,the operation draft is becoming deeper and deeper.It is necessary to research and develop new ultra-deep-water drilling vessel,to study the design method and key design technology of drilling vessel,and carry out intellectual property reservation.The paper is aiming at the most advanced ultra-deep water new drilling rig drilling vessel,taking the basic structure design of practical engineering research and development project as the direction,the main design market,design requirements,key technologies and development direction of the drilling vessel are introduced.With emphasis on the analysis of the requirements of each classification society for the submission of the basic structure design process of the drilling vessel,the load and calculation method of drilling vessel are analyzed,and the calculation process of bending moment and shearing force of each classification society is compared.For the new ultra-deep water drilling vessel,the hull girder design and check is carried out.The longitudinal strength,i.e.section modulus check,global yield strength evaluation of cargo hold and simplified fatigue strength and fatigue damage calculation of key joints are carried out respectively.According to the requirements of the classification notation of the ultra-deep water drilling vessel,the follow-up is carried out step by step for assessment of ship strength.The main research contents and conclusions are as follows:(1)To find out the main design and development direction of drilling vessels through the main design market,domestic main research contents,design requirements and key technologies,etc.(2)Through the analysis of the main classification Societies' codes and application software,to confirm the requirements for submitting the basic structure design of ultra-deep water drilling vessels,including Initial Structural Design(ISE)and Total Strength Analysis(TSA),as well as optional notation Dynamic Loading Approval(DLA),Spectrum Fatigue Analysis(SFA).As to the analysis results of DLA and SFA,the structure will be maintained unchanged where the results is lower than the total strength assessment,while the local structure is strengthened where the result is higher than the total strength assessment(TSA).(3)According to ABS Classification Society Code,the calculation of drilling vessel design load is analyzed,and the bending moment and shear force of the main classification society on the overall longitudinal strength of the hull are compared.The principle of hull girder design checking is studied,and the design flow of the hull section design method is determined,and the structural dimensions and material selectors of the standard design calculation are determined.Method: Select the key dangerous section to check the section strength.The results show that the section modulus of each cross section of the hull meets the basic requirements of the overall longitudinal strength of the structure.(4)Establishing a mid-ship model to analyze yield strength and buckling strength.For gross scantling modeling,post-processing calculation of global strength should be carried out according to stress reduction method and stress combination method.The results show that the yield buckling strength of the hull structure meets the requirements of the code.(5)Through simplified fatigue analysis and calculation of cargo hold model,high stress area is scanned according to corresponding S-N curve,critical areas are determined,calculation with refined mesh is carried out for selected critical area,and inner calculation spreadsheet is programmed to calculate accumulate fatigue damage.The results show that the structural fatigue strength meets the requirements of the code.