Effect of Specimen Length on Structural and Sealability Evaluation of Tubular Connections in HPHT and Thermal Wells

2021 ◽  
Author(s):  
Jueren Xie
Keyword(s):  
Structural Integrity ◽  
Lateral Buckling ◽  
Specimen Length ◽  
Element Analysis ◽  
Evaluation Program ◽  
Current Test ◽  
Industry Standards ◽  
Test Component ◽  
Connection Design ◽  
The Impact

Abstract Premium connection designs are typically evaluated and qualified to broadly adopted industry standards, such as ISO 13679 (2019) and API RP 5C5 (2017) procedures for testing casing and tubing connection in High Pressure and High Temperature (HPHT) wells up to temperatures of 180°C, and ISO/PAS 12835 (2013) for testing casing connection in thermal wells that experience temperatures from 180°C to 350°C. The primary focus of these qualification protocols is to evaluate the sealing capacity and structural integrity of the candidate connection design under loads representative of the conditions that the connection will experience through the well's life cycle. The test specimens consist of the coupling and the pipe segments on both sides of the coupling. While it may be desirable to evaluate test specimens with lengths equal to that of the field product to capture the temperature, pressure and mechanical loads on the specimen, it is advantageous to limit the length for purposes including handling and controlling the size and cost of the evaluation program. It has been observed that the test results can be affected by the specimen length, so the proper selection of specimen length is a key aspect of these evaluation programs. Current test protocols provide the requirement of a minimum unsupported length for allowing the tests to simulate the strain localization condition. On the other hand, if the unsupported length exceeds a critical value, the test specimens may experience lateral buckling, and preventing buckling adds complexity and cost to the test program. No guidelines have been given in the protocols on the maximum pup length requirement for preventing lateral buckling. Therefore, a better understanding of the impact of specimen length is warranted in order to achieve more reliable and accurate results from the testing program. This paper presents an investigation of the effect of specimen length on the structural integrity and sealability of premium connections based on Finite Element Analysis (FEA). Parametric FEA was completed to determine the impact of specimen length for several sizes of a generic premium connection design under API RP 5C5 (2017) HPHT well and ISO/PAS 12835 (2013) thermal well conditions. Based on the analysis results, recommendations are made to improve and enhance the guidelines for identifying a suitable specimen length for the test component of an evaluation program.

scholarly journals Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

2015 ◽  
Vol 12 (19) ◽  
pp. 5871-5883 ◽  
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield
Keyword(s):  
Climate Change ◽  
Finite Element ◽  
Structural Integrity ◽  
Geometric Model ◽  
Algal Growth ◽  
Coralline Algae ◽  
Rocky Shores ◽  
Element Analysis ◽  
Scan Data ◽  
The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

Flexible Flowline Walking Tendency on Seabed With Longitudinal Undulations and Transverse Gradients

2018 ◽  
Author(s):  
Graeme Roberts ◽  
T. Sriskandarajah ◽  
Gianluca Colonnelli ◽  
Arnaud Roux ◽  
Alan Roy ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Gradients ◽  
Radius Of Curvature ◽  
Bend Radius ◽  
Lateral Buckling ◽  
Element Analysis ◽  
Slip Tendency ◽  
Start Ups ◽  
The Impact

A method of carrying out a combined axial walking and lateral buckling assessment for a flexible flowline has been developed using finite element analysis. The method overcomes limitations of screening assessments which could be inconclusive when applied either to a flexible flowline on an undulating seabed with transverse gradients or to one that buckles during hydrotest. Flexible flowlines that were to be surface-laid on a seabed with longitudinal undulations and transverse gradients were assessed using the method. The flexible flowlines were simulated in their as-laid state, and the simulation incorporated hydrotest pressure and the pressure & temperature gradients and transients associated with multiple start-ups. The objective was to quantify the axial walking and lateral slip tendency of the flexible flowlines and the impact that walking might have on the connected end structures. The lateral buckle locations predicted by finite element analysis were compared to a post-hydrotest survey and the radius of curvature from analysis was compared to the minimum bend radius of the flexible.

Advances in Bonded Insulated Rail Joints to Improve Product Performance

2014 ◽  
Author(s):  
Korhan Ciloglu ◽  
Peter C. Frye ◽  
Scott Almes ◽  
Sidney Shue
Keyword(s):  
Structural Integrity ◽  
Load Transfer ◽  
Material Selection ◽  
Field Testing ◽  
Insulation Material ◽  
Element Analysis ◽  
Heavy Haul ◽  
And Performance ◽  
Critical Components ◽  
The Impact

Insulated rail joints (IJs) are critical components of railroad track infrastructure. It is essential for IJs to maintain railroad track’s structural continuity while having an important role in track circuit design and implementation. The structural integrity and performance of IJs have been recognized as a key interest area by the railroads as a result of increasing average axle loads and train traffic. While there are many different designs offered by various manufacturers around the globe, the main approach utilized by heavy haul railroads in the US, Canada and many other countries has been to use adhesively bonded insulated joint bars between two rails. This approach offers the benefit of a composite assembly where the continuous bond between rails and bars offer a geometrically uninterrupted transfer of loads between rails and bars. The main components of a bonded IJ are joint bars, insulation material, adhesive, endpost, and bolts or other fasteners. This paper summarizes recent design improvements on these components. The main focus areas of the research are bar design, bar material selection, insulator and adhesive selection and using a novel endpost design for load transfer between two rails. Track support conditions’ impact on IJ performance has also been considered as a factor influencing IJ performance in track and incorporated in the study. The impact of insulation material selection on IJ performance is discussed. Finite element analysis was used extensively in the study where the analysis results were supported by laboratory and field testing. The results of the study indicate dynamic stresses in bonded IJs can be reduced nearly 40% in joint bars by a combination of design improvements on IJ components. Improved bar material properties are expected to lead to considerably reduced risk of bar fatigue failures in track.

Concrete LNG GBS Terminal Ship Collision Study

2008 ◽  
Author(s):  
Fuqiang Wu ◽  
Frank Puskar ◽  
Pascinthe Saad
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Integrity ◽  
Impact Resistance ◽  
Liquefied Natural Gas ◽  
Element Analysis ◽  
Benchmark Tests ◽  
Ship Collision ◽  
Numerical Tool ◽  
The Impact

Concrete Gravity Based Structure (GBS) provides an opportunity for the storage of Liquefied Natural Gas (LNG) and represents one of the key elements of an LNG receiving and regasification terminal. The impact resistance of an offshore LNG GBS against accidental ship collision needs to be evaluated. Nonlinear elasto-plastic Finite Element Analysis (FEA) provides a useful numerical tool to assess the damage and evaluate the overall structural integrity of the GBS following a ship collision. In the work presented, a large capacity tanker was modeled using FEA and simulated to collide into a prototype concrete LNG GBS. An efficient, two-step approach was applied to estimate the damage levels caused by the striking tanker considering different approach speeds. Various benchmark tests were conducted to validate the steel and concrete FEA models to ensure the reliability of the analysis. The simulation shows that certain collisions can cause damage to both the tanker bow and the LNG GBS, depending upon the collision speed and the configuration of the colliding bodies. However, these collisions do not always result in a breach of the LNG containment. The results of this type of assessment can be used to assist in designing the LNG GBS to improve its impact resistance. The results can also be used in risk studies typical of these types of facilities.

Ballistic penetration damages and energy absorptions of stacked cross-plied composite fabrics and laminated panels

2020 ◽  
Vol 29 (9) ◽  
pp. 1465-1484
Author(s):  
Qingsong Wei ◽  
Bohong Gu ◽  
Baozhong Sun
Keyword(s):  
Finite Element ◽  
Structural Integrity ◽  
Impact Damage ◽  
Ballistic Impact ◽  
Body Armor ◽  
Element Analysis ◽  
Laminated Panels ◽  
Composite Fabrics ◽  
The Impact ◽  
Ballistic Penetration

Flexible fabrics have been widely used in body armor designs. Here we report ballistic impact damage of stacked cross-plied composite fabric and cross-plied laminated panels. The ballistic impact behaviors of stacked cross-plied composite fabric and cross-plied laminated panel have been tested with fragment-simulating projectiles under the strike velocity 550–600 m/s to explore the influence of the layers combination of fabric target on ballistic impact. Two types of macroscopic anisotropy continua finite element models based on fabric targets structures are established to analyze the ballistic mechanism of stacked cross-plied composite fabric and cross-plied laminated panels. The impact damage morphologies and energy absorptions have also been compared between the tests and finite element analysis results. We have found the stacked fabric construction absorbed more energy than their counterpart cross-plied laminated panel, while the laminated panel shows better structural integrity and stability during ballistic penetration.

scholarly journals Update on Ongoing Tank Car Crashworthiness Research: Predicted Performance and Fabrication Approach

2008 ◽  
Author(s):  
Michael Carolan ◽  
David Tyrell ◽  
Brandon Talamini
Keyword(s):  
Structural Integrity ◽  
Impact Load ◽  
The Body ◽  
Rigid Punch ◽  
Load Path ◽  
Element Analysis ◽  
Structural Foam ◽  
Improved Design ◽  
Energy Absorbing ◽  
The Impact

Research is currently underway to develop strategies for maintaining the structural integrity of railroad tank cars carrying hazardous materials during collisions. This research, sponsored by the Federal Railroad Administration (FRA), has focused on four design functions to accomplish this goal: blunting the impact load, absorbing the collision energy, strengthening the commodity tank, and controlling the load path into the tank. Previous papers have been presented outlining the weight and space restrictions for this new design, as well as the approach being taken in developing the design. The performance goals for the new car have also been outlined. A key goal for the new design is the ability to contain its lading at four times the impact energy of the baseline equipment. Presently, a preliminary design has been developed that will incorporate these four functions together. This new design features a conventional commodity tank with external reinforcements to strengthen the tank. The reinforced tank is situated on a structural foam cradle, within an external carbody. This carbody has been designed utilizing welded steel sandwich panels. The body is designed to take all of the inservice loads, removing the commodity tank from the load path during normal operations. Additionally, the carbody panels will serve as an energy-absorbing mechanism in the event of a collision. Preliminary steps for fabricating and assembling the new tank car design have been outlined. These steps were developed with the intention of paralleling existing tank car fabrication process as much as is practical. Using the commercial finite element analysis (FEA) software ABAQUS/Explicit, the improved design has been analyzed for its response to an impact by a rigid punch. Simulations of two generalized impact scenarios have been made for this rigid punch impacting the improved tank car head as well as the improved tank car shell. Results of these analyses, including the force-displacement curves for both impacts, are presented within this paper. These results show that an improved-design tank car can contain the commodity for a head impact with eight times the energy of the baseline car, and four times the energy for a shell impact.

Structural Integrity of a Spar in Collision With a Large Supply Vessel

2013 ◽  
Author(s):  
Xinguo Ning ◽  
Bob L. Zhang ◽  
Sudhakar Tallavajhula
Keyword(s):  
Kinetic Energy ◽  
Structural Integrity ◽  
Impact Force ◽  
High Energy ◽  
Progressive Damage ◽  
Element Analysis ◽  
Impact Speed ◽  
Integrity Assessment ◽  
Damage Models ◽  
The Impact

The objectives of this study are to establish numerical approaches to evaluate the structural integrity of a generic Spar hull in collision with a large supply vessel and to reveal its progressive collision damage characteristics. Dynamic and nonlinear finite element analysis is implemented using ABAQUS/Explicit module [1] respectively for two collision scenarios. One is a realistic simulation where the impact kinetic energy governed by an initial impact speed and total mass of a ship is gradually depleted during the collision. The other is a simplified analytical method where the impact speed of a ship bow throughout the collision is constant or the total impact energy is unlimited. With a combination of calibrated material progressive damage models and Mises plasticity, progressive collision damages of the hull structures are accurately captured for structural integrity assessment. The collision energy absorption characteristics, the impact force-deformation curves, the progressive damage modes and the correlation between the impact force, kinetic energy and damages are revealed. Based on numerical investigation, the two analytical scenarios are compared and the implication for the design analysis is elucidated. As a complementary to the ABS code [2], the alternative collision damage criterion in ABS MODU [3] applicable to column-stabilized units is justified to be applicable to a Spar subjected to high-energy impact.

Tangguh Project: In-Service Buckling Design of Offshore Pipelines With Major Uncertainties on Soil Characterization and Seabed Mobility

2021 ◽  
Author(s):  
Sabrina Bughi ◽  
Luigi Foschi ◽  
Lorenzo Marchionni ◽  
Roberta Vichi ◽  
Yansa Zulkarnain
Keyword(s):  
Structural Integrity ◽  
Mitigation Measures ◽  
Soil Characterization ◽  
Operating Life ◽  
Lateral Buckling ◽  
Natural Sand ◽  
Pull Out ◽  
Pipeline Route ◽  
The Impact ◽  
Soil Pipe

Abstract This paper is based on the experience made during the design and installation of an offshore pipeline recently completed in Indonesia, where a 24” subsea production pipeline (16km long in 70m water depth) was found susceptible during design to lateral buckling. Buckling is a well understood phenomenon. However, this project was characterized by major uncertainties mainly driven by soil characterization, soil zonation, soil-pipe interaction, seabed mobility and seabed liquefaction. These uncertainties have played a key role in the in-service buckling design. In particular, extreme pipeline embedment scenarios ranging from fully exposed to fully covered (due to natural sand transportation) were accounted with a significant impact on soil-pipe interaction. To limit the development of excessive strain within the acceptance criteria, a mitigation strategy based on interacting planned buckles has been adopted installing three Buckle Initiators (BI) along the pipeline route. During design great efforts have been spent with the aim to demonstrate the robustness of the proposed solution. 3-D FEM simulations with ABAQUS have been performed taking into account the pipeline route including route curves and the sea bottom profile and the buckle initiators with their main geometries. All uncertainties have been considered following a deterministic approach. The impact of environmental and accidental loads due to a potential trawl-gear interaction were assessed as well. The pipeline susceptibility to lateral and/or upheaval buckling along the sandwave areas has been analyzed as well in order to evaluate the need of mitigation measures suitable to freeze the pipeline configuration during the operating life. Finally, once the lateral buckling design philosophy was established, the cyclic expansion and walking behavior of the pipeline were assessed to verify the pipeline structural integrity at buckles, route curve pull-out and the accumulative pipeline expansion at spools. This paper presents all main engineering aspects faced during design and first feedbacks from field after the pipeline installation.

Lateral Buckling and Walking Design of a Pipeline Subjected to a High Number of Operational Cycles on Very Uneven Seabed

2014 ◽  
Author(s):  
Rafael F. Solano ◽  
Bruno R. Antunes ◽  
Alexandre S. Hansen ◽  
T. Sriskandarajah ◽  
Carlos R. Charnaux ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Structural Integrity ◽  
Mechanical Design ◽  
Lateral Buckling ◽  
Element Analysis ◽  
Control Approach ◽  
Temperature Conditions ◽  
Oil Export ◽  
Global Buckling

Global buckling is a behavior observed on subsea pipelines operating under high pressure and high temperature conditions which can jeopardize its structural integrity if not properly controlled. The thermo-mechanical design of such pipelines shall be robust in order to manage some uncertainties, such as: out-of-straightness and pipe-soil interaction. Pipeline walking is another phenomenon observed in those pipelines which can lead to accumulated displacement and overstress on jumpers and spools. In addition, global buckling and pipeline walking can have strong interaction along the route of a pipeline on uneven and sloped seabed, increasing the challenges of thermo-mechanical design. The P-55 oil export pipeline has approximately 42km length and was designed to work under severe high pressure and high temperature conditions, on a very uneven seabed, including different soil types and wall thicknesses along the length and a significant number of crossings. Additionally, the pipeline is expected to have a high amount of partial and full shutdowns during operation, resulting in an increase in design complexity. During design, many challenges arose in order to “control” the lateral buckling behavior and excessive walking displacements, and finite element analysis was used to understand and assess the pipeline behavior in detail. This paper aims to provide an overview of the lateral buckling and walking design of the P-55 oil export pipeline and to present the solutions related to technical challenges faced during design due to high number of operational cycles. Long pipelines are usually characterized as having a low tendency to walking; however in this case, due to the seabed slope and the buckle sites interaction, a strong walking tendency has been identified. Thus, the main items of the design are discussed in this paper, as follows: lateral buckling triggering and “control” approach, walking in long pipelines and mitigate anchoring system, span correction and its impact on thermo-mechanical behavior.

scholarly journals Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

2015 ◽  
Vol 12 (4) ◽  
pp. 3855-3877
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield
Keyword(s):  
Climate Change ◽  
Finite Element ◽  
Structural Integrity ◽  
Geometric Model ◽  
Algal Growth ◽  
Coralline Algae ◽  
Rocky Shores ◽  
Element Analysis ◽  
Scan Data ◽  
The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focussed on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA), suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE-models that represent coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasizing the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

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