Finite Element Investigation on the Tensile Armor Wire Response of Flexible Pipe for Axisymmetric Loading Conditions Using an Implicit Solver

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Alireza Ebrahimi ◽  
Shawn Kenny ◽  
Amgad Hussein
Keyword(s):  
Finite Element ◽  
Oil And Gas ◽  
Mechanical Response ◽  
Numerical Models ◽  
Oil And Gas Industry ◽  
Parameter Study ◽  
Loading Conditions ◽  
Flexible Pipe ◽  
Axisymmetric Loading ◽  
Implicit Solver

Composite flexible pipe is used in the offshore oil and gas industry for the transport of hydrocarbons, jumpers connecting subsea infrastructure, and risers with surface platforms and facilities. Although the material fabrication costs are high, there are technical advantages with respect to installation and performance envelope (e.g., fatigue). Flexible pipe has a complex, composite section with each layer addressing a specific function (e.g., pressure containment, and axial load). Continuum finite element modeling (FEM) procedures are developed to examine the mechanical response of an unbonded flexible pipe subject to axisymmetric loading conditions. A parameter study examined the effects of: (1) pure torsion, (2) interlayer friction factor, (3) axial tension, and (4) external and internal pressure on the pipe mechanical response. The results demonstrated a coupled global-local mechanism with a bifurcation path for positive angles of twist relative to the tensile armor wire pitch angle. These results indicated that idealized analytical- and structural-based numerical models may be incomplete or may provide an accurate prediction of the pipe mechanical response. The importance of using an implicit solver to predict the bifurcation response and simulate contact mechanics between layers was highlighted.

An Effective Computational Parametric Appraoch for Optimization of Adhesively Bonded Tubular Joints Subjected to Torsion Loading

2006 ◽  
Author(s):  
Ramin Hosseinzadeh ◽  
Nader Cheraghi ◽  
Farid Taheri
Keyword(s):  
Finite Element ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Design Parameters ◽  
Loading Conditions ◽  
Adhesively Bonded ◽  
Gas Industry ◽  
Tubular Joints ◽  
Composite Pipes ◽  
Joint Length

Due to their low manufacturing cost, low stress concentration and ease of maintenance, adhesively bonded joints are now one of the most commonly and widely used joining systems in various industrial applications. As the use of composites gains popularity in oil and gas industry, the use of such joints for joining composite pipes is also gaining demand. The design and analysis methodologies applied to these joints under different loading conditions are however non-standard and rather controversial. The inherently complicated equations governing the behaviour of these joints have also impeded their use among the design engineers. As stated, however, as the use of composite pipes gains more popularity in oil and gas industry, the need for standardization of the methodology used for designing such joints becomes more essential. This paper discusses the details of 2D axis-symmetric and full-3D finite element models developed using the ABAQUS commercially available FEM software [1] for modeling and characterizing a series of adhesively bonded tubular joints used in isotropic and orthotropic pipes. The parametric script module of ABAQUS was used to systematically investigate the influence of several design parameters (such as the adhesive thickness, joint length, joint diameter, pipe material, and loading conditions), which govern the performance of such joints. The influence of various parameters specific to composite pipes (including the effect of laminate stacking sequence) was also investigated. Generated from the investigations was a set of useful design curves that provide the relationships among the parameters governing the behaviour of the joints. An important feature of the approach is its ability to establish the most optimized and effective joint length. The integrity of the optimization procedure was evaluated by comparing the response of the joints designed based on the developed design curves with those analyzed in detail by the finite element method (FEM).

Finite Element Analysis of Casing Material Behavior in Steam Injection Well Operations

2015 ◽  
Vol 799-800 ◽  
pp. 196-200
Author(s):  
Abhilash M. Bharadwaj ◽  
Sonny Irawan ◽  
Saravanan Karuppanan ◽  
Mohamad Zaki bin Abdullah ◽  
Ismail bin Mohd Saaid
Keyword(s):  
Finite Element ◽  
Oil Recovery ◽  
Thermal Stresses ◽  
Oil And Gas ◽  
Extreme Temperature ◽  
Injection Pressure ◽  
Oil And Gas Industry ◽  
Steam Injection ◽  
Material Behavior ◽  
Element Analysis

Casing design is one of the most important parts of the well planning in the oil and gas industry. Various factors affecting the casing material needs to be considered by the drilling engineers. Wells partaking in thermal oil recovery processes undergo extreme temperature variation and this induces high thermal stresses in the casings. Therefore, forecasting the material behavior and checking for failure mechanisms becomes highly important. This paper uses Finite Element Methods to analyze the behavior two of the frequently used materials for casing - J55 and L80 steels. Modeling the casing and application of boundary conditions are performed through Ansys Workbench. Effect of steam injection pressure and temperature on the materials is presented in this work, indicating the possibilities of failure during heating cycle. The change in diameter of the casing body due to axial restriction is also presented. This paper aims to draw special attention towards the casing design in high temperature conditions of the well.

Validation of Sleeve Weld Integrity and Workmanship Level Development

2006 ◽  
Author(s):  
Robert Lazor ◽  
Brock Bolton ◽  
Aaron Dinovitzer
Keyword(s):  
Finite Element ◽  
Numerical Models ◽  
Full Scale ◽  
Loading Conditions ◽  
Element Analysis ◽  
Service Failures ◽  
Applied Loading ◽  
Fea Modeling ◽  
Field And Laboratory Conditions ◽  
Scale Data

Full encirclement repair sleeves with fillet-welded ends are often used as permanent repairs on pipelines to reinforce areas with defects, such as cracks or corrosion. In-service failures have occurred at reinforcing sleeves as a result of defects associated with the sleeve welds, such as hydrogen-induced cracks and undercut at the fillet welds, inadequate weld size, and sleeve longitudinal seam ruptures. This work was undertaken to support the development of tools for sleeve design and for conducting an engineering assessment to determine the tolerable dimensions of flaw indications at full encirclement repair sleeves. In particular, the project was intended to validate the stresses estimated using finite element analysis (FEA) models against actual in-service loading conditions experienced at reinforcing sleeves. The experimental work focused on the collection of full-scale experimental data describing pipe and sleeve strains for the following field and laboratory conditions: • Strains induced by sleeve welding, • Strains induced by pressurization of the sleeved pipe, • Strains induced by pressurization of the sleeved pipe and the annulus between the pipe and sleeve. Finite element models of the field and laboratory sleeved pipe segments were developed and subjected to the same applied loading conditions as the full-scale sleeved pipe segments. Comparisons of the measured strains against those estimated using FEA were completed to determine the ability of the models to predict the behaviour of the sleeved pipe segments. Comparisons were made to illustrate the relative strain levels and deformation trends, the accuracies of the strain predictions and trends in changes with pressure, the differences in behaviours between tight and loose fitting sleeves, and the effects of pressurizing the annulus between the pipe wall and sleeve. The analysis of the field data and FEA modeling predictions led to several conclusions regarding to use of numerical models for predicting sleeved pipe behaviour and weld flaw acceptance: • FEA results demonstrated behaviours that were consistent with full scale data, • Trends in the FEA predicted strains agreed with the full-scale data, • FEA models describing the effects of gaps between the pipe and sleeve and annulus pressurization agreed with field experience and engineering judgment, • Evaluation of the significance of root and toe flaws can be completed by extending the models validated in this work.

scholarly journals Comparative Study of CFD and LedaFlow Models for Riser-Induced Slug Flow

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3733
Author(s):  
Rasmus Thy Jørgensen ◽  
Gunvor Rossen Tonnesen ◽  
Matthias Mandø ◽  
Simon Pedersen
Keyword(s):  
Slug Flow ◽  
Oil And Gas ◽  
Cfd Simulation ◽  
Numerical Models ◽  
Oil And Gas Industry ◽  
Test Facility ◽  
Cfd Model ◽  
Two Phase ◽  
Transient Model ◽  
Vof Model

The goal of this study is to compare mainstream Computational Fluid Dynamics (CFD) with the widely used 1D transient model LedaFlow in their ability to predict riser induced slug flow and to determine if it is relevant for the offshore oil and gas industry to consider making the switch from LedaFlow to CFD. Presently, the industry use relatively simple 1D-models, such as LedaFlow, to predict flow patterns in pipelines. The reduction in cost of computational power in recent years have made it relevant to compare the performance of these codes with high fidelity CFD simulations. A laboratory test facility was used to obtain data for pressure and mass flow rates for the two-phase flow of air and water. A benchmark case of slug flow served for evaluation of the numerical models. A 3D unsteady CFD simulation was performed based on Reynolds-Averaged Navier-Stokes (RANS) formulation and the Volume of Fluid (VOF) model using the open-source CFD code OpenFOAM. Unsteady simulations using the commercial 1D LedaFlow solver were performed using the same boundary conditions and fluid properties as the CFD simulation. Both the CFD and LedaFlow model underpredicted the experimentally determined slug frequency by 22% and 16% respectively. Both models predicted a classical blowout, in which the riser is completely evacuated of water, while only a partial evacuation of the riser was observed experimentally. The CFD model had a runtime of 57 h while the LedaFlow model had a runtime of 13 min. It can be concluded that the prediction capabilities of the CFD and LedaFlow models are similar for riser-induced slug flow while the CFD model is much more computational intensive.

Prediction of Burst Pressure of Pipes With Geometric Eccentricity

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Zhanfeng Chen ◽  
Weiping Zhu ◽  
Qinfeng Di ◽  
Wenchang Wang
Keyword(s):  
Finite Element ◽  
Function Method ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Element Model ◽  
Burst Pressure ◽  
Gas Industry ◽  
Tresca Criterion ◽  
Special Case ◽  
Theoretical Results

An analytical model was proposed in this paper to predict the burst pressure of a pipe with geometric eccentricity. With application of the complex elastic potential function method in a bipolar coordinate system, the authors first derived an analytical solution of stresses in an eccentric pipe and then obtained the formula of predicting burst pressure by combining the solution with the Tresca criterion. Finally, the effect of eccentricity and the ratio of thickness to diameter of pipe on burst pressure were discussed. Our results show that a slight eccentricity can significantly decrease the burst pressure. In the special case of zero-eccentricity for a concentric pipe, our model yields results that are consistent with experiments data published by others and theoretical results predicted by models proposed by other researchers without considering the effect of eccentricity. In the case of eccentricity for an eccentric pipe, the calculating results of our model are also consistent with that of finite element model (FEM). The theoretical model and results presented in this paper have a broader application in predicting the burst pressure for pipes commonly used in oil and gas industry.

Application of Finite Element Modelling in the Qualification of Large Diameter Unbonded Flexible Risers

2002 ◽  
Author(s):  
Wenchao Zhang ◽  
Justin Tuohy
Keyword(s):  
Finite Element ◽  
Finite Element Modelling ◽  
Oil And Gas ◽  
Large Diameter ◽  
Full Scale ◽  
Flexible Pipe ◽  
Element Modelling ◽  
Norsk Hydro ◽  
Flexible Risers ◽  
Full Scale Testing

Unbonded flexible pipe has a proven track record in the offshore oil and gas industry for more than 20 years. The product is synonymous with the use of floating production systems spanning the water column and connecting subsea structures to facilitate the retrieval of hydrocarbons, provision of water injection systems and the export of processed or semi-processed fluids to main trunk pipelines or onshore. Unbonded Flexible pipe is a technically complex multi-layer structure of helically wound metallic wires and tapes and extruded thermoplastics. In 1996 Wellstream was awarded a major contract for the supply of flexible risers and flowlines as part of the Norsk Hydro Troll Olje Gas Province Development located in 350m water depth 80km west of Bergen. The development consists of two main fields, Troll East (31/3 and 31/6) and Troll West (31/2) which together have an estimated production life in excess of 50 years, making it one of the worlds largest offshore developments. Norsk Hydro is responsible for the development and operation of the production facilities. The scope of supply included 15-inch internal diameter, 213 barg design pressure, dynamic risers for the export of oil and gas from the platform to shore. At contract award, Wellstream was finalising the location of their European Manufacturing site, a facility which would have the capability of manufacturing unbonded flexible pipe with external diameters up to 24-inches. The design, manufacture and qualification of a large diameter oil and gas export riser for service in the Norwegian sector of the North Sea, considered to be one of the most severe environments in the offshore industry, provided unique challenges and attributes. These risers have now been in service for over two year, following an extensive qualification programme. This paper provides an insight into the integrated approach adopted during qualification with the successful application of finite element technology to aid full-scale testing. During a full-scale test program a finite element simulation of a 15 metre long prototype pipe was performed with special emphasis on the evaluation of contact forces between the flexible pipe and a bend limiting structure. The finite element analysis program package ANSYS is chosen for this simulation due to its special feature of contact/target elements. The paper illustrates that the use of Finite Element Modelling is indeed capable of predicting the observed behaviour of prototype risers, which are subjected to a series of dynamic load cases, in a Dynamic Test Rig (DTR). Finally, the paper concludes that focus should now be given to the advantages of using finite element tools that are verified by full scale testing to reduce development costs and schedules.

Use of Finite Element Analysis for Stud Pre-Tension Determination of Large Diameter Integral Flanges With Ring Joint Gaskets

2010 ◽  
Author(s):  
Upali Panapitiya ◽  
Haoyu Wang ◽  
Syed Jafri ◽  
Paul Jukes
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Oil And Gas ◽  
Large Diameter ◽  
Three Dimensional ◽  
Oil And Gas Industry ◽  
Element Analysis ◽  
Axial Forces ◽  
Three Dimensional Finite Element

Large diameter integral steel flanges are widely used in many applications in the oil and gas industry. The flanges of nominal pipe sizes, 26-inch and above with ring-joint gaskets as specified in ASME B 16.47 Standard, are used in the offshore applications for the transportation of oil and gas from production facilities. These pipelines require flanged connections at end terminations, mid-line tie-ins and expansion loops. The conventional design of large diameter steel flanges is based on one-dimensional analytical methods similar to the procedure in ASME VIII Boiler and Pressure Vessel Code, Division 1 Appendix 2. The effects of axial forces and bending moments are approximated by calculating an equivalent pressure. This usually results in conservative designs for the large flanges because it estimates the required stud pre-tension based on the assumption that the gasket will be unloaded entirely to a minimum stress, whereas only a small section of the gasket is subjected to low stress. This technical paper presents the quasi-static, nonlinear, and three-dimensional finite element models of large diameter steel flanged joint for the determination of stud pre-tension and change of stud tension under various loading conditions. The finite element analysis results are compared with the results obtained by using the equivalent pressure method and flange “Joint Diagram”.

scholarly journals Burst Strength Analysis of Casing With Geometrical Imperfections

2006 ◽  
Vol 129 (4) ◽  
pp. 763-770 ◽  
Author(s):  
Xiaoguang Huang ◽  
Yanyun Chen ◽  
Kai Lin ◽  
Musa Mihsein ◽  
Kevin Kibble ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Strength Analysis ◽  
Element Analysis ◽  
Burst Strength ◽  
The Finite Element Analysis ◽  
Geometrical Imperfections ◽  
Major Factors

Accurately predicting the burst strength is very important in the casing design for the oil and gas industry. In this paper, finite element analysis is performed for an infinitely long thick walled casing with geometrical imperfections subjected to internal pressure. A comparison with a series of full-scale experiments was conducted to verify the accuracy and reliability of the finite element analysis. Furthermore, three predictive equations were evaluated using the test data, and the Klever equation was concluded to give the most accurate prediction of burst strength. The finite element analysis was then extended to study the effects of major factors on the casing burst strength. Results showed that the initial eccentricity and material hardening parameter had important effects on the burst strength, while the effect of the initial ovality was small.

Development and Experimental Calibration of Numerical Model Based on Beam Theory to Estimate the Collapse Pressure of Flexible Pipes

2015 ◽  
Author(s):  
Jefferson Lacerda ◽  
Marcelo I. Lourenço ◽  
Theodoro A. Netto
Keyword(s):  
Structural Integrity ◽  
Oil And Gas ◽  
Numerical Models ◽  
Beam Theory ◽  
Gas Production ◽  
Operating Conditions ◽  
Flexible Pipe ◽  
Experimental Calibration ◽  
Collapse Pressure ◽  
Flexible Pipes

The constant advance of offshore oil and gas production in deeper waters worldwide led to increasing operational loads on flexible pipes, making mechanical failures more susceptible. Therefore, it is important to develop more reliable numerical tools used in the design phase or during the lifetime to ensure the structural integrity of flexible pipes under specific operating conditions. This paper presents a methodology to develop simple finite element models capable of reproducing the behavior of structural layers of flexible pipes under external hydrostatic pressure up to collapse. These models use beam elements and, in multi-layer analyses, include nonlinear contact between layers. Because of the material anisotropy induced by the manufacturing process, an alternative method was carried out to estimate the average stress-strain curves of the metallic layers used in the numerical simulations. The simulations are performed for two different configurations: one where the flexible pipe is composed only of the interlocked armor, and another considering interlocked armor and pressure armor. The adequacy of the numerical models is finally evaluated in light of experimental tests on flexible pipes with nominal internal diameters of 4 and 6 in.

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