Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

The Study of Hull Piping Stress Analysis of Semi-Platform
Jiuhuan Cheng, Zhiyuan JI, Junjie Lei
Engineering Company of Offshore Oil Engineering Co., Ltd.
Tianjin, China

CAESAR II and ANSYS software and the relevant data, using ASME
B31.1 as the calculation and evaluation standard, the calculation
method for hull piping stress analysis of Deepwater Semi-Platform has
been studied, the hull piping loads suitable for harsh environment andcomplex hull deformation conditions have been selected, the hullpiping stress analysis load cases have been compiled, and the hullsuper-high penetration riser, non-metallic piping of ballast system ,SCR
riser and a series of complex piping stress analysis have been studied.
The new type pipe support suitable for the hull structure is proposed,
and the best recommended scenario is obtained.

ABSTRACTThe Deepwater Semi-Platform is one of the most important equipmentsfor the development of deepwater oil and gas fields. As a large
deepwater floating structure, it is a comprehensive development andprocessing center and it can provide oil and gas processing, storaging
and loading/unloading, power supply, personnel life and other functions.
The design of a Deepwater Semi-Platform in China is still in its infancy,
facing great challenges, especially for the hull piping stress analysis.
Taking the hull piping of a Deepwater Semi-Platform as an example,
based on CAESAR II and ANSYS software and the relevant data at
home and abroad, using ASME B31.1 as the calculation and evaluation
standard, the calculation method for hull piping stress analysis of
Deepwater Semi-Platform has been studied, the hull piping loads
suitable for harsh environment and complex hull deformations havebeen selected, the hull piping stress analysis load cases have been
compiled, and the hull super-high penetration riser, non-metallic pipingof ballast system, SCR(Steel Catenary Riser) riser and a series ofcomplex piping stress analysis have been studied. The new type pipe
support suitable for the hull structure is proposed, and the best
recommended scenario is obtained. The best recommended scenario
and a better example design for the future of hull piping has beenprovided.

Through simulation analysis, the non-flexible compensation design
scenario of hull piping has been completed firstly. By comparing thedifferences of piping stress level, loads of fixed hull penetration, naturalfrequency, it has not only accurately evaluated the stress impact of hull
penetration parts on the piping system, but also ensured the integrity ofthe design of piping system in narrow space, and summarized the best
recommended design scenario of hull piping. It is also applied to thefirst self-designed and built Deepwater Semi-Platform in China. The
best recommended scenario and a better example design for the futureof hull piping has been provided.

THE DEEPWATER SEMI-PLATFORM AND THE HULLPIPINGThe Deepwater Semi-Platform is a of the important equipments for
deepwater oil and gas development, compared with FPSO (Floating
Production Storage and Offloading System), it has better stability andgreater operating water depth and it can resist stronger wind and waves.
This paper is based on the first Deepwater Semi-Platform
independently developed, designed and built in China. The operatingwater depth is up to 1500m, which is composed of topside and hull, andthe hull is composed of columns and lower floating bodies, as shown in
Figure 1.

KEY WORDS: Deepwater Semi-Platform, Hull, Ballast System,
CAESAR II, Piping stress analysis.

INTRODUCTION
The Deepwater Semi-Platform is one of the most important equipments
for the development of deepwater oil and gas fields. The design of a
Deepwater Semi-Platform in China is still in its infancy, facing greatchallenges, especially for the hull piping stress analysis. Taking the hull
piping of a Deepwater Semi-Platform as an example, based on

The hull piping is located in the columns and lower floating body of thehull, including bilge system, ballast system, tank sweeping system,
seawater system, fresh water system, fuel oil system, cargo oil system,
fire water system, etc.. The calculation and analysis of hull piping is761