Independent Design Verification of Deepwater SCRs for the Application in South China Sea

Abstract Through nearly 30 years of design and implementation, Steel Catenary Risers (SCRs) have been found to have the advantages of relatively low cost and good adaptability to floating platform’s motion. SCRs have been selected as the production and export riser solution for Lingshui 17-2 (termed LS17-2) field in South China Sea, which consists of a subsea production system, a deep-draft semi-submersible, and an export riser/pipeline. This paper investigates independent design verification of deepwater SCRs for the application in South China Sea. This paper first introduces a SCR system for LS17-2 project. The field for this project is located in northern South China Sea, with water depth of 1220m to 1560m. This paper describes the design verification methodology, procedure, riser computer modelling, extreme challenges, findings, and technical discussions. The independent design verification includes riser sizing, adjacent riser interference, cathodic protection, dynamic strength analysis, Vortex-Induced Vibration (VIV) analysis, wave motion fatigue analysis, semi-submersible Vortex-Induced Motion (VIM) fatigue analysis, and riser installation. Sensitivity study was carried out to demonstrate the accuracy of the results and the robustness of the riser design. SCR designs are extremely sensitive to environmental loading and the motion characteristics of a host platform. The independent design verification shows that the riser governing location of global performance is at the riser Touch Down Point (TDP) region. Compression forces in an SCR touchdown area can be caused by extreme or survival load cases. Among the fatigue damage sources, fatigue damage contributions are dominated by wave motion, VIM and VIV. This paper finally summarizes the findings from the independent verification work. It concludes that the SCR system design for LS17-2 development meets the requirements of API 2RD design code.

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Steel Catenary Riser Dynamic Analysis for Deepwater Applications in South China Sea

29th International Conference on Ocean, Offshore and Arctic Engineering: Volume 5, Parts A and B ◽

10.1115/omae2010-20256 ◽

2010 ◽

Cited By ~ 1

Author(s):

Jinbao Lin ◽

Dongbao Wang ◽

Tao Qi

Keyword(s):

South China Sea ◽

Wall Thickness ◽

South China ◽

Fatigue Analysis ◽

Current Data ◽

Strength Analysis ◽

Functional Requirements ◽

Motion Generation ◽

Floating Platform ◽

China Sea

This paper first describes the functional requirements of the Steel Catenary Risers (SCRs) for the deepwater applications in South China Sea. Spar is assumed to be the floating platform for the study in this paper. SCR wall thickness is preliminarily selected according to the industry codes. Dynamic strength analysis is preformed to verify the riser wall thickness. Fatigue analysis is then carried out to evaluate fatigue strength for the riser. The fatigue analysis covers different sources such as wave motion, ambient current, and Spar Vortex-Induced Motion (VIM). The metocean data in South China Sea are used for the vessel global motion generation. The current data are used for computing the riser fatigue caused by Vortex-Induced Vibration (VIV). Total fatigue damage for the risers is evaluated. Conclusions are finally drawn from the work in this paper.

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Deepwater Steel Catenary Riser System Design for Lingshui 17-2 Project

10.1115/omae2021-63881 ◽

2021 ◽

Author(s):

Ning He ◽

Hu Yang ◽

Fanli Xu ◽

Yongming Cheng

Keyword(s):

South China Sea ◽

System Design ◽

South China ◽

Oil And Gas ◽

Low Cost ◽

Northern South China Sea ◽

Steel Catenary Riser ◽

China Sea ◽

Scr System ◽

The Impact

Abstract A riser is a key component for transporting produced oil and gas from the subsea wells to the surface production vessel. Through nearly 30 years of design and implementation, Steel Catenary Risers (SCRs) have been found to have the advantages of relatively low cost and good adaptability to floating platform’s motion. This paper investigates deepwater SCR system design for the Lingshui 17-2 (termed LS17-2) project. This paper first introduces a SCR system for the LS17-2 project. The field for this project is located in the northern South China Sea, with water depth of 1220m to 1560m. LS17-2 consists of a subsea production system, a deep-draft semi-submersible (SEMI), and an export riser/pipeline. The platform was designed to have a large storage capacity with a variable draft during its operation. Based on deepwater SCR engineering experience, the key SCR design challenges are summarized from the engineering executive perspective. The challenges to the SCR system design for the LS17-2 project include harsh environment condition in South China Sea and the impact on fatigue design for the requirement of 30-years’ service life. They call for design optimization and innovative ideas. The engineering design and analysis are discussed together solutions. To demonstrate the deepwater SCR system design for LS17-2 project, examples are provided to illustrate the challenges and solutions. The experience learned from this paper should have significant relevance to future SCR design.

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