Reliability Modelling of Subsea Cluster Manifolds Based on the Fault Tree Analysis

Author(s):  
Yingying Wang ◽  
Fangqiu Li ◽  
Menglan Duan ◽  
Houfa Liu ◽  
Jiandong Gu

The cluster manifold becomes an essential part in a subsea production system and it has been widely used in the development of ultra-deepwater oil and gas fields. One hand, it can gather the production fluid from subsea wells. On the other hand, it can distribute water, gas and chemical agents from the floating production system to each subsea well. Hence, the failure of subsea cluster manifolds may not only lead to the stagnation of production wells and economic losses but also cause environmental pollution and human health in severe cases. Therefore, the reliability of subsea cluster manifolds is quite of importance and it should be studied for the safety service of the subsea production system. Based on the fault tree analysis (FTA), this paper will discuss the failure cause of six well slots subsea cluster manifolds in LiWan 3-1 gas field in China South Sea. Considering the pipeline structure, control system and flow assurance, the fault trees of subsea cluster manifolds are built. Meanwhile, the importance degrees of each elementary event are ranked orderly and the minimum cut sets are obtained through analyzing the structure important of the FTA. The failure major reasons are obtained and the preventive measures are proposed, which could have some guiding significance for the operations of subsea cluster manifolds system in China South Sea.

Author(s):  
MARY ANN LUNDTEIGEN ◽  
MARVIN RAUSAND

This article presents a practical approach to reliability assessment of a complex safety instrumented system that is susceptible to common cause failures. The approach is based on fault tree analysis where the common cause failures are included by post-processing the minimal cut sets. The approach is illustrated by a case study of a safety instrumented function of a workover control system that is used during maintenance interventions into subsea oil and gas wells. The case study shows that the approach is well suited for identifying potential failures in complex systems and for including design engineers in the verification of the reliability analyses. Unlike many software tools for fault tree analysis, the approach gives conservative estimates for reliability. The suggested approach represents a useful extension to current reliability analysis methods.


2014 ◽  
Vol 986-987 ◽  
pp. 1619-1623
Author(s):  
Xiao Lei Zhao ◽  
Le Ping Chu ◽  
Xing Wei Guo ◽  
Guo He Yu ◽  
Jin Yu Chen

With the development of offshore oil and gas field enters into deep water constantly, subsea production system has become the main development mode in deep water development. Pipeline End Termination (PLET) is common facilities in subsea production system and is used to provide subsea tieback interface. An embedded type PLET has been adopted in Panyu 35-1/35-2 Gas field with the water depth of 194 to 338 m. Factory Accept Test (FAT) is very important for the subsea production facilities, and the references is very limited due to technical security. This paper in detail states the flow chart, master equipment, purpose and precautions for each test of FAT for PLET, which collects great technology for the development of subsea production system.


2014 ◽  
Vol 986-987 ◽  
pp. 975-979
Author(s):  
Xiao Lei Zhao ◽  
Zhi Xing Wu ◽  
Le Ping Chu ◽  
Xing Wei Guo ◽  
Jin Yu Chen

With the development of offshore oil and gas field enters into deep water constantly, subsea production system has become the main development mode in deep water development. Subsea Inline manifold (ILM) is common facilities in subsea production system and is used to gather oil and gas from the side subsea wells. Two subsea ILMs has been adopted in Panyu 35-1/35-2 Gas field with water depth range from 194 to 338 m in South China Sea. System integration test (SIT) is very important for the subsea production facilities. This paper states the flow chart, master equipment, purpose and precautions for each test of ILM SIT, which collects great technology for the development of subsea production system.


Author(s):  
Ruzica Nikolic ◽  
Dusan Arsic ◽  
Aleksandra Arsic ◽  
Zivce Sarkocevic ◽  
Dragan Cvetkovic ◽  
...  

Premature failure or damage of parts and components of the oil and gas well piping, as well as pipelines for transport of oil and gas, are generally caused by the simultaneous influence of a large number of technological, metallurgical, structural and exploitation factors. Therefore, the convenient structural solutions, which provide the mechanical safety of parts and integrity of structures, can be realized only through total comprehension of their behavior in various operation regimes. Importance of technical diagnostics for monitoring and state analysis of welded pipes/pipelines in oil industry is considered in this paper. An analysis of causes of the welded pipes failures in exploitation has been performed through use of the fault tree analysis. Based on the suggested structure of a database, regarding the causes of failure, possibilities are presented to set measures for prevention of damage and failure of welded pipes/pipelines and for extension of their service life. A suggestion for improvement of the organizational scheme for monitoring the state and maintenance of welded pipes/pipelines during the exploitation has been made, as well.


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