SCR Fatigue Feasibility Prediction for Deepwater FPSO Applications

Author(s):  
Sherry Xiang ◽  
Peimin Cao

Many of the recent offshore oil and gas discoveries in the world have occurred in deep waters, at locations far away from the existing subsea infrastructure. Floating Production Storage and Offloading systems (FPSOs) are the preferred field development solutions for those locations with mild and moderate environments. The simplest fluid transfer system between the seabed and the FPSO is a simple catenary configuration, with Steel Catenary Risers (SCRs) as the preferred solution for deep water, high pressure and high temperature applications. This paper introduces an effective engineering SCR fatigue screening methodology for FPSO applications. The focus of this study is to better understand SCR fatigue performance at Touch Down Point (TDP) and develop a simple but reasonable correlation between FPSO porch motion and the riser dynamic stress response at TDP. This methodology enables one to perform the porch motion statistics analysis and the riser dynamic response analysis independently. By using the wave screening approach, SCR fatigue feasible map can be effectively developed. The paper presents an example performing the fatigue screening evaluation. SCR feasibility design flow chart for FPSO application is also addressed. Particular for FPSO application in a new development, the fatigue feasibility prediction approach along with the strength feasibility check can help the project make the informative decision on the overall FPSO and riser system selection at the early stage of the development.

Author(s):  
Liping Sun ◽  
Xiongliang Yao ◽  
Zhenghong Hu

Floating Production, Storage and Offloading (FPSO) system has been used widely in the offshore oil and gas industries worldwide. In recent years, FPSO concept has been deployed in deep and ultra-deepwater field development including West of Africa, Offshore Brazil, and Offshore China. Meanwhile, more and more deepwater risers have been deployed from concept to offshore installation. Compared to other type deepwater floaters (e.g. Spar, TLP, Semisubmersible), the severe motion characteristics of an FPSO makes the riser concept selection and design much more challenges. Other constraints imposed by field reservoir properties (e.g. high temperature\high pressure), disconnection requirements for early production FPSO system, and significant increase in water depth even exclude some riser concepts. This paper presents detailed evaluation of potential deepwater riser concepts applicable for an FPSO. Among the deepwater concepts, steel catenary risers (SCR), flexible risers, hybrid risers have been successfully deployed to FPSO application. In addition, there are also other viable riser concepts for FPSO application including lazy wave SCR, Tension Leg Riser (TLR), Hybrid ‘S’ Riser System (HySR), Hybrid Catenary Riser (HCR), and more to come. The evaluation of deepwater riser concepts for FPSO application is conducted in terms of technical feasibility, design constraints, track records, fabrication, offshore construction, and cost with focus on the existing and field proven riser concepts. Technical challenges and technology gaps are highlighted. The technical feasibility of some of the riser concepts for certain FPSO application has been demonstrated through analysis and calculation. Novel ideas have been generated for particular requirements. Particular attention is paid to the discussion with the application to offshore China. This paper shows the steel riser and hybrid riser are the most viable ones for deep and ultra-deepwater FPSO. Flexible riser and hybrid riser are the preferred solution for FPSO in China.


2021 ◽  
Author(s):  
David Christensen ◽  
Andrew Re

Abstract The National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) is Australia's independent expert regulator for health and safety, structural (well) integrity and environmental management for all offshore oil and gas operations and greenhouse gas storage activities in Australian waters, and in coastal waters where regulatory powers and functions have been conferred. The Australian offshore petroleum industry has been in operation since the early 1960s and currently has approximately 57 platforms, 11 floating facilities, 3,500km of pipelines and 1000 wells in operation. Many offshore facilities are now approaching the end of their operational lives and it is estimated that over the next 50 years decommissioning of this infrastructure will cost more than US$40.5 billion. Decommissioning is a normal and inevitable stage in the lifetime of an offshore petroleum project that should be planned from the outset and matured throughout the life of operations. While only a few facilities have been decommissioned in Australian waters, most of Australia's offshore infrastructure is now more than 20 years old and entering a phase where they require extra attention and close maintenance prior to decommissioning. When the NOGA group of companies entered liquidation in 2020 and the Australian Government took control of decommissioning the Laminaria and Corallina field development it became evident that there were some fundamental gaps in relation to decommissioning in the Australian offshore petroleum industry. There are two key focus areas that require attention. Firstly, regulatory reform including policy change and modification to regulatory practice. Secondly, the development of visible and robust decommissioning plans by Industry titleholders. The purpose of this paper is to highlight the importance and benefit of adopting good practice when planning for decommissioning throughout the life cycle of a petroleum project. Whilst not insurmountable, the closing of these gaps will ensure that Australia is well placed to deal with the decommissioning challenge facing the industry in the next 50 years.


Author(s):  
Zhao Wang ◽  
Wei Qin ◽  
Xiaojie Zhang ◽  
Jiannan Zhao ◽  
Yong Bai

Abstract The steel lazy wave riser has been used in deep-water oil and gas field development because it has good adaption to the movement of the upper platform and economic efficiency. The typical design criterion and design flow of steel lazy wave riser are introduced in this paper. The design method and the equivalence principle of distributed buoyancy modules are given. The formulas of equivalent hydrodynamic parameters are derived in this paper. The influences of distributed buoyancy modules (DBM) and the buoyancy factor on the configuration of the riser, the top tension, and the bending moment distribution are discussed and summarized. The distribution law of effective stress response along the pipe can be analyzed by dynamic analysis, and it provides reference for the global design of steel lazy wave riser.


Author(s):  
V. I. Salygin ◽  
S. V. Berezinskiy

AbstracUThe article reviews the problems caused by the conflict of interests between certain Southeast Asian countries and other states, China foremost, which aroused from oil and gas field development on disputable offshore sections. At the same time the positions of the region's leading transnational corporations in the field of oil and gas policy and their relationships with the countries-ASEAN (Association of South East Asian Nations) members are outlined. Separately are represented the foreign policy stands of Indonesia, Vietnam, Brunei, Philippines and Malaysia on territorial disputes over offshore oil and gas fields. These processes are pushing both European and American business to abandon the conventional schemes and accept the new conditions of their activity in Southeast Asia.


2021 ◽  
Author(s):  
Novita Dwi Putri Nugraheni ◽  
Jie Li

Abstract The objective of the paper is to develop a mixed integer nonlinear programming (MINLP) model for optimum design and scheduling of offshore oil and gas field development in respect to simultaneous consideration of economic and environmental impact. The model is utilized as a tool for decision making management in conceptual stage. Nonlinear reservoir behavior and floating demand constraint are incorporated to improve accuracy of the solution. This paper utilizes mathematical programming techniques to address the design and scheduling problem of offshore oil and gas field development. Field development problem is first formulated into a multi-objective MINLP model incorporating many realistic features such as nonlinear reservoir behavior and floating demands. The objectives are to maximize net present value (NPV) and minimize total environmental impact (TEI) simultaneously. Environmental impact is assessed using the ReCiPe2016 method. Augmented ε-constraint method (AUGMECON) is then employed to solve the proposed multi-objective MINLP model to generate the Pareto-optimal front that is able to assist decision maker selecting the most preferred solution. The performance of the proposed modelling framework is investigated on a set of problem which consists of 2 reservoirs, 2 FPSOs, 2 customers and 5-years planning horizon. First model with single objective function to maximize NPV can be solved effectively within short computational time. The solution gives optimum decision of design, investment, production schedule, and transportation regardless the environmental impact. Then, simultaneous optimization of multi-objective MINLP with different value of ε-constraint generates multiple development schemes and objective function values. The results indicate trade-off between maximizing NPV and minimizing TEI. It is possible to obtain maximum NPV of USD 2.4 trillion at the expense of TEI which is 307.518 or to generate minimum TEI of 16.65 at the expense of NPV which is USD 74.368 billion. All possible solutions within extreme values range are presented in form of a Pareto-optimal front where TEI and NPV are plotted in x and y-axis respectively. It will assist the company to select the most preferred solution based on NPV. Consequently, the selected option brings corresponding value of TEI. Additionally, the Pareto optimal front also allows decision maker to have more flexibility to compromise between economic and environmental issues. This is the first study to consider environmental impact in the offshore oil and gas field development. Many realistic operational features such as nonlinear reservoir behavior and floating demands are also incorporated. In addition to that, the proposed framework yields a powerful tool to assist decision maker selecting the most preferred solution that satisfies their criteria in both economic and environmental aspects.


2018 ◽  
Vol 10 (7) ◽  
pp. 2469 ◽  
Author(s):  
Myung-Hun Kim ◽  
Eul-Bum Lee ◽  
Han-Suk Choi

Engineering, Procurement, and Construction (EPC) contractors with lump-sum turnkey contracts have recently been suffering massive profit losses due to re-works and schedule delays in offshore oil and gas EPC megaprojects. The main objective of this research is to develop and implement a detail engineering completion rating index system (DECRIS) to assist EPC contractors to optimize fabrication and construction works schedules while minimizing potential re-work/re-order. This is achieved through adequate detail design development and results in minimizing schedule delays and potential liquidated damages (i.e., delay penalties). The developed DECRIS was based on findings from an extensive review of existing literature, industry-led studies, expert surveys, and expert workshops. The DECRIS model is an evolution, and improvement of existing tools such as the project definition raking index (PDRI) and front-end loading (FEL) developed specifically for the early stage of engineering maturity assessment (i.e., planning, basic design, and front-end engineering design (FEED)), prior to EPC projects. The DECRIS was evaluated and validated with thirteen sample as-built offshore megaprojects completed recently. When the DECRIS was applied to the completed projects post-hoc, a correlation (R-squared 0.71) was found between DECRIS scores and schedule/cost performances. This is much superior to the PDRI-Industrial model’s correlation (R-squared 0.04), which was primarily devised for owners’ basic engineering or FEED completion assessment. Finally, as a means of further validation, project schedule and cost performance of an ongoing project was predicted based on the correlations found on the thirteen completed projects. The resultant predicted schedule and cost performance was well matched with the current project performance status. Based on the accuracy of the DECRIS model found in the validation, said model is an effective prospective tool for EPC contractors to manage their engineering and procurement/construction risks during the initial detail design stages.


Author(s):  
Jingyu Zhu ◽  
Kang Liu ◽  
Guoming Chen ◽  
Gaogeng Zhu

Dual derrick operations are widely used for field development during offshore drilling. During this process, complex operations and complicated hydrodynamic interaction may contribute to the interference collisions of parallel strings. In this context, this study addresses interference collisions for parallel strings during the deepwater dual derrick operation. To analyze the response of parallel strings a mechanical model for deepwater parallel strings is established. Moreover, Huse wake model and strip model are used for calculating the hydrodynamic influence in different wake fields. The research results validate that the collision will occur during the operation considering the hydrodynamic wake shielding effects and interference evaluation criterion. The increasing platform offsets and surface current are the leading causes of parallel strings collisions. To avoid the risk of interference collisions an innovative procedure for operability envelopes is developed by synthesizing the platform offsets and surface currents. The proposed operability envelopes method for parallel strings is automatically completed which can save much workforce and resources. A case study on deepwater drilling in the South China Sea has been applied to verify the effectiveness of these methods. Besides, the proposed methodology can effectively reduce collision accidents and provide technical support for the offshore oil and gas exploration.


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