NUMERICAL INVESTIGATIONS ON THE EFFECTS OF SEABEDSHALLOW SOILS ON A TYPICAL DEEPWATER SUBSEAWELLHEAD SYSTEM

Brodogradnja

article

Zhou, Xingkun¹  Chen, Jinghao²  Ge, Zhengguang³  Zhao, Tong²  Li, Wenhua¹ 

[1] Department of Marine Engineering, Dalian Maritime University, Dalian, National Center for International Research of Subsea Engineering Technology and Equipment, Dalian Maritime University;Beijing Key Laboratory of Pipeline Critical Technology and Equipment for Deepwater Oil & Gas Development, Beijing Institute of Petrochemical Technology;National Center for International Research of Subsea Engineering Technology and Equipment, Dalian Maritime University

关键词: Subsea wellhead;    Seabed soil;    Mechanical behaviour;    Nonlinear spring;   

DOI  :  10.21278/brod73301

学科分类：工程和技术（综合）

来源: Brodarski Institut

【 摘 要 】

Deepwater subsea wellheads may be significantly threatened under extreme seaconditions and operations, especially when the seabed is composed of very soft clayproperties. A numerical model of a deepwater wellhead system is established using the classicocean pipe element and nonlinear spring element of ANSYS to examine the behaviors ofsubsea wellheads in diverse seabed soil. Nonlinear spring elements coded in the APDLlanguage are used to model three types of seabed soils: very soft soil, soft soil, and firm soil.The dynamic and quasi-static behaviors of the wellhead system in the typical coupled anddecoupled models of the drilling riser system are particularly investigated in depth. Theeffects of the nonlinear seabed soil properties on the detailed wellhead are realisticallysimulated using time domain and extremum analysis. The results show that the softer theseabed soil, the greater the displacement, rotation angle, curvature, and bending moment ofdeepwater subsea wellheads. When the seabed soil reaches a particular depth, the mechanicalcharacteristics of the wellheads under the three types of seabed soil conditions are almostsimultaneously close to zero. Overall, several conclusions reached in this study may providesome useful references for design and stability analysis.

【 授权许可】

CC BY