Reliability Analysis of Jack-Up Platforms Based on Fatigue Degradation

Abstract

Generally, jack-up structures are used for production drilling and exploration of hydrocarbons. The combination of mobility and the behavior as a fixed structure in operational conditions has made it an important structure in the offshore industry over the last 40 years. When a jack-up structure has been in operation for a great part of its original design-life and intention is there to extend the usage of this structure at a specific location, an investigation on fatigue degradation of the structure is an essential factor that has to be carried out before taking any decision. Fatigue is the process of damage accumulation in material due to stress fluctuation caused by variation of loads in service time. The fatigue failure occurs when accumulated damage has exceeded a critical level. In this paper, the remaining fatigue capacity of the jack-up structure is considered as an indicator for adequate use of the structure. It can be specified based on the difference between design-fatigue and fatigue experienced by the structure. The design-fatigue can be determined based on fluctuation of loads during the lifetime of the structure and experienced fatigue is specified by the load conditions, which the structure has experienced during its service time. When the information on the load conditions which the structure has experienced in its service time is available or known precisely, determination of the remaining fatigue capacity could be carried out by using the Palmgren–Miner’s rule. In practice, uncertainties are present in loads and characteristics of material. Hence it will be reasonable to determine the remaining fatigue reliability of the structure by the reliability methods. In this paper, based on a crack propagation approach and achieved information from inspection, it is shown that the remaining fatigue reliability of jack-up structures could be determined and updated by using a Bayesian procedure in the duration of the service time.

Identifying the required infrastructure to improve the jack-up maintenance process based on effective criteria in the Persian Gulf

“…A wide range of studies have been performed in the field of drilling industry and shipyards, examined from different points of view such as maintenance and repair of jack-ups and the cost of maintenance, industry markets, shipyards, and jack-up legs’ analysis) Pisano et al , 2019; Guede, 2019; Nam et al , 2017; Li et al , 2018; Barlas and Izci, 2018; Shazzad Hosaain et al , 2018; Apergis et al , 2017; Kaiser, 2017; Ha et al , 2015; Zhao et al , 2014; Namkug and Ha, 2014; Xian-Gang and Yong, 2012; Pande et al , 2013; Perrons and Richards, 2013; Kaiser and Snyder, 2013; Cao et al , 2012; Zhang et al , 2012; Celebi and Vardar, 2008; Kaiser, 2008; Shabakhty et al , 2003; Morandi et al , 2001), which can help to understand and achieve the conclusive goal of the paper. The articles are divided into three sections, including first part: the jack-up market, second part: the jack-up R&M and third part: shipyards.…”

“…The main questions of this research are: which equipment is needed for rigs R&M, what kind of equipment the shipyard has, which equipment is more efficient and what criteria in rigs R&M are important for experts and owners. Other research has focused on repairing the jack-ups' legs, fixing the corrosion of the bodies and legs and mentioning criteria such as cost and time (Pisano et al , 2019; Guede, 2019; Shazzad Hosaain et al , 2018; Apergis et al , 2017; Kaiser, 2017; Zhao et al , 2014; Kaiser and Snyder, 2013; Xian-Gang and Yong, 2012; Pande et al , 2013; Perrons and Richards, 2013; Cao et al , 2012; Zhang et al , 2012; Kaiser, 2008; Shabakhty et al , 2003; Morandi et al , 2001), while other important criteria are not investigated. In addition, past studies have only touched on the types of shipyards and their equipment (Li et al , 2018; Nam et al , 2017; Ha et al , 2015; Namkug and Ha, 2014; Kaiser and Snyder, 2013; Cao et al , 2012; Celebi and Vardar, 2008; Celebi and Vardar, 2006) failing to survey all required equipment.…”

Condition Assessment Techniques for Aged Fixed-Type Offshore Platforms Considering Decommissioning: a Historical Review

“…It is claimed that the approach is able to reduce the number of structural analyses required for probabilistic analysis (Chin 2005). The effective use of response surface depends on the proper selection of sampling points (Shabakhty et al 2003). In the method, mean and standard deviation of basic random variables are utilised in enhancing the efficiency and accuracy of the simulations (Bucher and Bourgund 1990).…”

Comparative Study of Structural Reliability Assessment Methods for Fixed Offshore Structures

“…Thus, a fixed offshore platform gradually deteriorates due to degradation issues like an extreme wave, current, fatigue, seismic effects, etc. [8]. Hostile and destructive oceanic conditions play a vital role in reducing strength capacity [9].…”