Structural Integrity Assessment Method And Practice Of Panyu 4-2A/5-1A Jacket

Jacket is the key support structure of offshore platform.Those jackets are facing low fatigue life and short structure reserve strength.Platforms structure integrity have a great challenge.This paper take Panyu4-2A/5-1A jackets as a sample.Panyu oilfields was developed in trough period.Design company made a good effort in structural optimization in order to reduce cost.During oilfield production period,platforms were modified for drilling and production platform from wellhead platform.Since the Panyu Oilfields have been put into production,it attaches great importance to the study of the integrity management of the jacket.A lot of research work has been carried out to analyze the characteristics of PY 4-2A/5-1A jacket.This paper researchPY4-2A/-1A jacket structural integrity study using the latest risk based assessment method.It is to solve jacket low fatigue and short structure reserve strength and make jacket inspection plan.The paper carried out the detailed assessment for the risk and special challenge faced by existing jacket structure;based on further investigating to the relevant integrity assessment result,a special risk based method used to evaluate the reliability of the structure,and the failure frequency and consequence were assessed via quantity approaching;then the make a reasonable integrity maintenance strategy to help provide the basic methodology and technical assurance to the safety operation of the platform.Based on the above analysis,many jacket structural members and joints have stress level higher than allowable stress,many joints have fatigue life less than design life.RBI analysis is performed to optimize inspection plan,make it more economical and reasonable.Inspection results show no crack or damage are found.The PY4-2A / PY5-1A jacket are able to keep operation with risk under control.It has been proved that the PY4-2A/5-1A jacket inspection plan and structural integrity assessment research achieve good economic benefits.It also has certain reference and demonstration significance to the sustainable development of oil field.