Sandwich Pipe: Reel-Lay Installation Effects

2015 ◽  
Author(s):  
Claudio Moura Paz ◽  
Guangming Fu ◽  
Segen Farid Estefen ◽  
Marcelo Igor Lourenço ◽  
John Alex H. Chujutalli
Keyword(s):  
Numerical Models ◽  
External Pressure ◽  
Experimental Models ◽  
Steel Pipes ◽  
Installation Effects ◽  
Collapse Resistance ◽  
Structural Resistance ◽  
Annular Layer ◽  
Collapse Behavior ◽  
Pva Fiber

Comprising an annular layer with adequate thermal insulation and structural resistance material enclosed by two concentric steel pipes, sandwich pipes could be an alternative for flowlines in ultra-deepwater for the pre-salt reservoirs in offshore Brazil. In this work, a numerical and experimental study was performed to investigate the collapse behavior of sandwich pipes considering the reel-lay installation method. Experimental models were manufactured using two different geometries of stainless steel pipes and strain hardening cementitious composites with PVA fiber (SHCC) in annular layer. One set of specimens was tested using a reel-lay apparatus and another set was kept intact. A hyperbaric chamber was then used to test both sets of specimens to collapse. The collapse resistance of the proposed sandwich structure was investigated, and the detrimental effect of the reeling strains to the collapse resistance was assessed. The numerical models simulated reeling and straightening loads during reel-lay installation and then the collapse under external pressure. The results were compared with experimental measurements and shown good agreement.

Collapse and Buckle Propagation of Sandwich Pipes: A Review

2013 ◽  
Author(s):  
Chen An ◽  
Menglan Duan ◽  
Segen F. Estefen
Keyword(s):  
Failure Modes ◽  
Oil And Gas ◽  
Research Work ◽  
External Pressure ◽  
Mechanical And Thermal Properties ◽  
Structural Resistance ◽  
Buckle Propagation ◽  
Collapse Behavior ◽  
Elastoplastic Constitutive Model ◽  
Core Materials

Sandwich pipes (SP) can be an effective solution for ultra-deepwater submarine pipelines, combining high structural resistance with thermal insulation. Most research work on this subject has been conducted at the subsea technology laboratory (LTS) of COPPE/UFRJ, with the aim of developing qualified pipes to transport deepwater oil and gas, especially for the pre-salt reservoirs at Offshore Brazil. This article reviewed most of the research done in recent years (2002–2012) on the buckling, collapse and buckle propagation of SP, which emphasized on the development of theoretical, experimental and numerical methods adopted to analyze such structural behavior of SP with different core materials. The main mechanical and thermal properties of the previously considered core materials were also given, together with the elastoplastic constitutive model for each material. The experimental and numerical results of collapse and buckle propagation under external pressure for SP were summarized. A general discussion of the mechanical failure modes of SP under external pressure was also provided. Besides, some suggestions for future work on collapse behavior and buckle propagation of SP were given.

Reeling Effect on the Ultimate Strength of Sandwich Pipes

2005 ◽  
Author(s):  
Xavier Castello ◽  
Segen F. Estefen
Keyword(s):  
Ultimate Strength ◽  
Numerical Models ◽  
Kinematic Hardening ◽  
External Pressure ◽  
Combined Loading ◽  
Collapse Pressure ◽  
Finite Element Software ◽  
Structural Resistance ◽  
Longitudinal Bending ◽  
Full Scale Tests

Sandwich pipes composed of two steel layers separated by a polypropylene annulus can be used for the transport of oil&gas in deepwaters, combining high structural resistance with thermal insulation in order to prevent blockage by paraffin and hydrates. In this work, sandwich pipes with typical inner diameters of those employed in the offshore production are analyzed numerically to evaluate the ultimate strength under external pressure and longitudinal bending as well as the effect of the reeling installation method on the collapse pressure. Numerical models were developed using the commercial finite element software ABAQUS. The validation was based on experimental results. The analyses for combined loading were performed using symmetry conditions and the pipe was reduced to a ring with unitary length. The analysis of bending under a rigid surface was simulated numerically according to the experiments performed using a bending apparatus especially built for full scale tests. Symmetry conditions were employed in order to reduce the analysis to a quarter of a pipe. Mesh sensitivity studies were performed to obtain an adequate mesh refinement in both analyses. The collapse pressure was simulated numerically either for the pre or post reeling process. Bauschinger effect was included by using kinematic hardening plasticity models. The influences of plasticity and out-of-roundness on the collapse pressure have been confirmed.

Enhanced Collapse Resistance of Compressed Steel Pipes

2014 ◽  
Author(s):  
Venkat R. Krishnan ◽  
David A. Baker
Keyword(s):  
Experimental Testing ◽  
Three Dimensional ◽  
External Pressure ◽  
Combined Loading ◽  
Finite Element Analyses ◽  
Forming Process ◽  
3D Finite Element ◽  
Steel Pipes ◽  
Collapse Resistance ◽  
Sensitivity Studies

Pipe collapse is a primary design consideration for deep water locations and offshore areas with sharp seabed curvatures or spans, where bending reduces collapse resistance due to ovalization. Previous numerical and experimental work has shown that collapse resistance of steel pipes can be enhanced significantly by using compression instead of expansion during the final stage of the pipe forming process. ExxonMobil has recently undertaken a rigorous numerical modeling and experimental testing program to investigate the collapse resistance of compressed (JCOC) steel pipes under combined loading of external pressure and bending, and this paper presents the main results from the program. The first part of the paper presents results of sensitivity studies from three dimensional (3D) finite element analyses (FEA) of the pipe forming process, and the second part focuses on the collapse modeling under combined loading as well as a comparison of the numerical results with the experiments. The results indicate that the collapse envelope for steel pipes under combined external pressure and bending can be enhanced by up to 35% by adopting pipe compression rather than expansion as the final step of the forming process.

A Comparative Wet Collapse Buckling Study for the Carcass Layer of Flexible Pipes

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Alfredo Gay Neto ◽  
Clóvis de Arruda Martins
Keyword(s):  
Analytical Model ◽  
Numerical Models ◽  
External Pressure ◽  
Plastic Layer ◽  
Plastic Behavior ◽  
Flexible Pipe ◽  
Equivalent Thickness ◽  
Collapse Pressure ◽  
Ring Model ◽  
Collapse Behavior

When there is a failure on the external sheath of a flexible pipe, a high value of hydrostatic pressure is transferred to its internal plastic layer and consequently to its interlocked carcass, leading to the possibility of collapse. The design of a flexible pipe must predict the maximum value of external pressure the carcass layer can be subjected to without collapse. This value depends on the initial ovalization due to manufacturing tolerances. To study that problem, two numerical finite element models were developed to simulate the behavior of the carcass subjected to external pressure, including the plastic behavior of the materials. The first one is a full 3D model and the second one is a 3D ring model, both composed by solid elements. An interesting conclusion is that both the models provide the same results. An analytical model using an equivalent thickness approach for the carcass layer was also constructed. A good correlation between analytical and numerical models was achieved for pre-collapse behavior but the collapse pressure value and post-collapse behavior were not well predicted by the analytical model.

scholarly journals Estimation of Damage Induced by Single-Hole Rock Blasting: A Review on Analytical, Numerical, and Experimental Solutions

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 29
Author(s):  
Mahdi Shadabfar ◽  
Cagri Gokdemir ◽  
Mingliang Zhou ◽  
Hadi Kordestani ◽  
Edmond V. Muho
Keyword(s):  
Structural Reliability ◽  
Numerical Models ◽  
Experimental Models ◽  
Rock Blasting ◽  
Discussion Section ◽  
Reliability Models ◽  
Fine Grain ◽  
Experimental Approaches ◽  
Engineering Projects

This paper presents a review of the existing models for the estimation of explosion-induced crushed and cracked zones. The control of these zones is of utmost importance in the rock explosion design, since it aims at optimizing the fragmentation and, as a result, minimizing the fine grain production and recovery cycle. Moreover, this optimization can reduce the damage beyond the set border and align the excavation plan with the geometric design. The models are categorized into three groups based on the approach, i.e., analytical, numerical, and experimental approaches, and for each group, the relevant studies are classified and presented in a comprehensive manner. More specifically, in the analytical methods, the assumptions and results are described and discussed in order to provide a useful reference to judge the applicability of each model. Considering the numerical models, all commonly-used algorithms along with the simulation details and the influential parameters are reported and discussed. Finally, considering the experimental models, the emphasis is given here on presenting the most practical and widely employed laboratory models. The empirical equations derived from the models and their applications are examined in detail. In the Discussion section, the most common methods are selected and used to estimate the damage size of 13 case study problems. The results are then utilized to compare the accuracy and applicability of each selected method. Furthermore, the probabilistic analysis of the explosion-induced failure is reviewed using several structural reliability models. The selection, classification, and discussion of the models presented in this paper can be used as a reference in real engineering projects.

Materials Selection for Sandwich Pipes Under the Combined Effect of Pressure, Bending and Temperature

2007 ◽  
Author(s):  
Allan R. de Souza ◽  
Theodoro A. Netto ◽  
Ilson P. Pasqualino
Keyword(s):  
Structural Strength ◽  
Material Selection ◽  
Low Cost ◽  
Polymeric Materials ◽  
External Pressure ◽  
Core Material ◽  
Annular Layer ◽  
Oil And Natural Gas ◽  
Longitudinal Bending ◽  
Logic Approach

Recent researches point to the great potential of the sandwich pipe conception for ultra deepwater exploitation and production of oil and natural gas. Its configuration is very simple and comprises two concentric metallic pipes with a core material, polymeric or ceramic, in the annulus. The main functions of the annular layer are: to provide satisfactory thermal insulation so as to avoid the formation of wax and hydrates along the pipeline during production shutdown; to improve the overall structural strength of the system. Polypropylene and cement have been recently proposed for these applications. The reason for the choice of these materials was the low cost and the extensive availability in industry. Here a systematic material selection approach is employed in order to assess the applicability of other polymeric materials. The attributes of materials needed to meet the design specification are thoroughly studied. The list of possible materials was enlarged and the modified digital logic approach is used with the purpose to define a top group of materials for further numerical comparative study. Finite element analyses are carried out to assess the structural strength of the sandwich pipe under pure external pressure or longitudinal bending and combined external pressure and bending. Additionally, the effect of thermal gradient is included to the numerical analyses to evaluate each pre-selected material of the top group. Results indicate that other potential materials such as PEEK and polycarbonate can improve the structural performance of the sandwich pipe conception and yet meet other several design criteria.

A Strain Energy-Based Equivalent Layer Method for the Prediction of Critical Collapse Pressure of Flexible Risers

2018 ◽  
Author(s):  
Xiao Li ◽  
Xiaoli Jiang ◽  
Hans Hopman
Keyword(s):  
Strain Energy ◽  
Critical Pressure ◽  
Numerical Models ◽  
Fe Model ◽  
Collapse Pressure ◽  
Layer Method ◽  
Flexible Risers ◽  
Collapse Behavior ◽  
Equivalent Properties ◽  
Equivalent Layer

Flexible risers are one kind of flexible pipes that transport fluid between subsea facilities and topside structures. This pipe-like structure consists of multiple layers and its innermost carcass layer is designed for external hydrostatic pressure resistance. For the flexible risers used in ultra-deep water fields, the critical collapse pressure of the carcass layers is one of the dominant factors in their safety design. However, the complexity of the interlocked carcass design introduces significant difficulties and constraints into the engineering analysis. To facilitate the anti-collapse analysis, equivalent layer methods are demanded to help construct an equivalent pipe that performs a similar collapse behavior of the carcass. This paper proposes a strain energy based equivalent layer method which trying to bridge the equivalence between those two structures by considering equivalent geometric and material properties for the equivalent layer. Those properties are determined through strain energy equivalence and membrane stiffness equivalence. The strain energy of the carcass is obtained through numerical models and is then used in a derived equation set to calculate the equivalent properties for the equivalent layer. After all the equivalent properties have been determined, an equivalent layer FE model is built and used to predict the critical pressure of the carcass. The prediction result is compared to that of the full 3D carcass model as well as the equivalent models that built based on other existing equivalent methods, which shows that the proposed equivalent layer method gives a better performance on predicting the critical pressure of the carcass.

On Some Factors Affecting Casing Collapse Resistance under External Pressure

2020 ◽  
Author(s):  
Bisen Lin ◽  
David Coe ◽  
Richard Harris ◽  
Timothy Thomas
Keyword(s):  
External Pressure ◽  
Factors Affecting ◽  
Collapse Resistance ◽  
Casing Collapse

The Effect of Length: Diameter Ratio on Collapse of Casing

1984 ◽  
Vol 106 (2) ◽  
pp. 160-165 ◽  
Author(s):  
N. C. Huang ◽  
P. D. Pattillo
Keyword(s):  
Axial Load ◽  
External Pressure ◽  
Field Application ◽  
Diameter Ratio ◽  
Finite Cylinder ◽  
Oil Well ◽  
Steel Mill ◽  
Cross Sectional ◽  
Axial Tension ◽  
Collapse Resistance

This paper presents an analysis of the cross-sectional collapse of a cylinder of finite length loaded simultaneously by an axial tension (which may be zero) and external pressure. The calculation is based on Sanders’ nonlinear shell equations with plasticity introduced via the concept of effective stress from a uniaxial tension test. The finite cylinder is an appropriate model of oil well casing as it undergoes quality control testing in the steel mill where the edges of the cylinder are usually fixed in the case of nonzero axial load and free in the case of zero axial load. However, in field application, the length: diameter ratio of casing is such that the cylinder may be considered infinite. Guidelines contained herein permit prediction of the collapse resistance of field casing from the results of mill tests performed on short samples.

Ultrasonic Measurement of Forced Diameter Variations in an Elastic Tube

1994 ◽  
Vol 16 (2) ◽  
pp. 124-142 ◽  
Author(s):  
Javier C. Berrios ◽  
Peder C. Pedersen
Keyword(s):  
Rigid Wall ◽  
External Pressure ◽  
Experimental Models ◽  
Elastic Tube ◽  
Ultrasonic Measurement ◽  
Time Shift ◽  
Correlation Technique ◽  
Pressure Function ◽  
Diameter Variation ◽  
Thin Walled Tube

This paper presents an ultrasonic measurement technique to determine an elasticity parameter, called the apparent compliance, in a thin-walled tube. The apparent compliance is obtained by ultrasound pulse-echo measurement of the diameter variation in response to an externally applied time-varying pressure function. Specifically, the diameter variation is obtained by tracking the time shift of the echoes from the front and back walls of the tube using a correlation technique. This technique is named the Forced Vibration Method (FVM). This approach to compliance measurement is distinctly different from compliance measurements using the blood function as excitation function, but is closely related to the elastic imaging concept. Two experimental models, termed the rigid wall model and the leg-like model, have been developed. These models allow the amplitude and frequency of the pressure function as well as the dimensions and properties of the tube to be varied. Results for the diameter variations vs. location along the tube and frequency of external pressure function are presented for both models.

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