Comparative Structural Analyses Between Sandwich and Steel Pipelines for Ultra-Deep Water

Author(s):  
I. P. Pasqualino ◽  
B. C. Pinheiro ◽  
S. F. Estefen

Pipe-in-pipe systems are usually composed of two concentric metal pipes with or without an insulation material in the annulus region. Design requirements for ultra-deep water pipelines motivated the development of a new pipe-in-pipe conception in which the annulus is filled with materials that combine low cost, adequate thermal insulation properties and good mechanical resistance. The aim of this ongoing research project is to evaluate the structural performance of sandwich pipes with two different options of core material. Because of their wide availability and relatively low costs, the materials considered in this study were cement and polypropylene for the annulus, with pipes made of API X-60 grade steel. In this paper, a three-dimensional finite element model considering material and geometric nonlinear behavior was developed. This numerical model was used to perform a parametric study to determine the collapse envelopes of different pipe-in-pipe configurations under combined bending and external pressure. The collapse envelopes were compared with others obtained for steel pipelines of equivalent collapse pressure. The study showed that the pipe-in-pipe systems with either cement or polypropylene cores are feasible options to ultra-deep water pipelines fulfilling concomitantly both the requirements of structural resistance and thermal insulation.

Author(s):  
Soheil Manouchehri

For un-bonded (sliding) Pipe-In-Pipe (PIP) systems, one of the main components is the centralizers (also called spacers). The main functions of the centralizers are to centralize the inner pipe inside the outer pipe, to transfer the loads between inner pipe and outer pipe and to safeguard the insulation material in the annulus from excessive compression during fabrication, installation and operation. Centralizers must also have good thermal insulation properties so that the heat loss is minimized. Different designs are now available for centralizers but the majority are based on two half shells which are bolted together. During fabrication, installation and operation, centralizers subject to different loads under which they are required to continue functioning properly. This paper provides an overview of centralizer design aspects and then focuses on the loading history during installation using reeling method. The main contributing parameters to centralizer loading during reeled installation technique are discussed and conclusions are drawn. It is believed that this will enable Pipeline Engineers to select the most appropriate material and design for centralizers.


Author(s):  
I. P. Pasqualino ◽  
M. I. Lourenc¸o ◽  
T. A. Netto

Sandwich pipes have been considered feasible conceptions for ultra deepwater pipelines, since they are capable to work at low temperatures and withstand high hydrostatic pressures. Sandwich pipelines are composed by inner and outer metallic pipes and a suitable core material which must provide high compression strength and good thermal insulation. The aim of this ongoing research is to study the quasi-static propagation of buckles in sandwich pipes. In this paper, a three-dimensional finite element model considering material and geometric nonlinear behavior is presented. The mesh discretization is determined through a detailed mesh sensitivity analysis. Some experiments with small scale models combining aluminum pipes and polypropylene as core material were carried out to calibrate the numerical model. The propagation pressure is evaluated under different bonding conditions between pipe layers.


2012 ◽  
Vol 178-181 ◽  
pp. 46-50
Author(s):  
Wang Ping Wu ◽  
Zhou Chen ◽  
Cheng Dong Li ◽  
Teng Zhou Xu ◽  
Jin Lian Qiu ◽  
...  

The insulation material VIP in building offers a new material for highly insulated constructions with just a fraction of the required insulation thickness compared to conventional thermal insulation materials. A VIP is basically composed of the core material, the barrier film and getters. Core materials of VIP are glass fiber, fumed silica, fiber-powder composite core. The barrier film covered by glass fiber textile is the protection of the envelope against surface damage and fire attack. We introduce the VIP elements, the system of VIPs in building application and external thermal insulation system with VIP.


2004 ◽  
Vol 72 (4) ◽  
pp. 599-608 ◽  
Author(s):  
Segen Farid Estefen ◽  
Theodoro Antoun Netto ◽  
Ilson Paranhos Pasqualino

Design requirements for pipelines regarding both ultimate strength and flow assurance in ultra deepwater scenarios motivated the development of a new sandwich pipe which is able to combine high structural and thermal insulation properties. In this concept, the annulus is filled with low cost materials with adequate thermal insulation properties and good mechanical resistance. The aim of this research work is to perform small-scale laboratorial tests and to develop a finite element model to evaluate the structural performance of such sandwich pipes with two different options of core material. After calibrated in view of the experimental results, a three-dimensional finite element model incorporating nonlinear geometric and material behavior is employed to perform strength analyses of sandwich pipes under combined external pressure and longitudinal bending. Ultimate strength envelopes for sandwich pipes are compared with those generated for single-wall steel pipes with equivalent collapse pressures. The study shows that sandwich pipe systems with either cement or polypropylene cores are feasible options for ultra deepwater applications.


2016 ◽  
Vol 47 (6) ◽  
pp. 1024-1037 ◽  
Author(s):  
Ahmed H Hassanin ◽  
Zeki Candan ◽  
Cenk Demirkir ◽  
Tamer Hamouda

Due to the significant and harmful effect of the global warming on our communities, health, and climate, the usage of thermal insulation material in building is must to decrease the energy consumption and to improve energy efficiency. On the other hand, the utilization of waste and biomass resources for developing new bio-based composite materials is attracting much attention for the environmental and socioeconomics. Therefore, in this study, thermal insulation bio-based composite panels from Tetra Pak® waste and wool fiber waste with different ratios were manufactured. Likewise, other sandwich bio-based composite panels were manufactured using Tetra Pak waste as a core material with glass woven fabric and jute wove fabric as skin materials. Thermal conductivity and thermal resistance results showed a significant improvement on thermal insulation properties of the developed biocomposite panels compared to the control samples made of plain Tetra Pak®.


Author(s):  
T. A. Netto ◽  
J. M. C. Santos ◽  
S. F. Estefen

Pipeline systems for deepwater applications must be designed to withstand operational loads and to give adequate thermal insulation to the hydrocarbon being transported. Sandwich pipelines composed by inner and outer steel pipes and either cement or polypropylene as core material are proposed here as viable alternatives to currently used pipe-in-pipe systems. The main advantage of these sandwich structures is that the core material and geometry can be selected so to provide both thermal insulation and good structural performance in conjunction with inner and outer pipes. In this paper, the structural behavior of such sandwich pipes under external pressure is studied through a series of small scale experiments and nonlinear numerical analyses based on the finite-element method.


Author(s):  
Guangming Fu ◽  
Claudio Moura Paz ◽  
John Alex Hernández Chujutalli ◽  
Marcelo Igor Lourenço ◽  
Dirney Bessa de Lima ◽  
...  

Sandwich pipes (SP) combining high structural resistance with thermal insulation have been considered as an effective solution for using in ultra deepwater pipelines. Research has been conducted at COPPE/UFRJ with different core materials aiming to develop qualified pipes to transport deepwater oil and gas, especially for the pre-salt reservoirs in offshore Brazil. SPs using SHCC material are easy to manufacture and cost-effective. Moreover, the composition of the SHCC material can be controlled to achieve structural requirements along with good thermal insulation. Investigation on the buckling under external pressure and feasibility of installation by reel-lay method is required. This study presents numerical analysis of the collapse, collapse propagation and bending of sandwich pipes with different geometries. The Drucker-Prager formulation is employed for SHCC constitutive model and it is calibrated through small-scale tests. Model geometries match full scale specimens manufactured and tested in bending apparatus and hyperbaric chamber. Numerical/experimental correlation is also presented.


Author(s):  
Erica Marley ◽  
Olav Aamlid ◽  
Leif Collberg

Recent developments in the offshore industry are resulting in an increasing demand for deep water pipelines. At greater water depths, the external pressure will be the governing parameter for wall thickness design, and the failure mode is collapse. DNV’s reliability based standard, DNV-OS-F101, uses the collapse capacity model and corresponding safety factors calibrated in the SUPERB Joint Industry Project, finalized in the mid 1990’s. Since then, a vast amount of research on collapse capacity of deep water pipelines is performed, indicating that it is time to re-visit the design equation and safety factors currently in use. This paper firstly summarizes the relevant collapse pressure equations for pipeline design. Secondly, the major points related to collapse capacity in SUPERB and DNV-OS-F101 are presented. Furthermore, results from an assessment of newer collapse tests of pipelines are described. Focus is on larger (UOE) pipes with D/t ratios less than 25, corresponding to water depths beyond 1000 m. The test results are compared to the outcome of earlier experimental projects. A difference between older and more recent tests is observed, with the newer having a considerably higher collapse capacity. Finally, a calibration of safety factors is performed, compared to existing factors and discussed.


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