Offshore Pipeline Installation: 3-Dimensional Finite Element Modelling

Author(s):  
Lorenzo Marchionni ◽  
Lombardi Alessandro ◽  
Luigino Vitali

The future offshore pipeline development projects envisage the installation of medium to large diameter pipelines (16″ to 32″ ND) transporting gas from the deep waters to the shallow water areas. The development of these deep water projects is limited by the feasibility/economics of the construction phase using the J-lay or the S-lay technology. In particular, the S-lay feasibility depends on the applicable tension at the tensioner which is a function of water depth, stinger geometry (length and curvature), and installation criteria. In this paper: – The challenges of future deep water offshore pipelines are briefly presented; – The installation criteria at the overbend, stinger tip and sagbend are discussed; – The ABAQUS FE Model, developed to simulate pipeline installation, is presented together with the pre- and post-processing program put in place; – The results of the developed ABAQUS FE Model are given considering two typical examples of deep water pipelines installed in the S-lay mode.

Author(s):  
Lorenzo Bartolini ◽  
Cristian Crea ◽  
Lorenzo Marchionni ◽  
Maurizio Spinazze` ◽  
Luigino Vitali

In the last thirty years, the attention of the offshore pipeline industry has been strongly focused on submarine pipelines crossing very uneven seabed. New pipelines crossing the uneven seabed of the Mediterranean Sea and of the North Sea and deep water pipelines crossing the uneven continental slope of the Gulf of Mexico are outstanding examples. Pipeline structural integrity may be threaten by large free-spanning sections between rocky peaks and deep depressions that may be coupled with the pipeline propensity to develop lateral/vertical deflection due to severe service conditions (High Pressure/High Temperature). Generally, these scenarios require mitigation measures aiming to control the development of excessive bending moment/deformation by means of Finite Element (FE) Modeling. FE Modeling gives a valuable contribution to the pipeline engineering at identifying a technical and cost effective solution since the early phase of the project. Finite Element (FE) Model approaches, based on standard structural finite element codes available on the market, such as ABAQUS, ADINA, ANSYS etc., are commonly used to analyze the effects of non-linearity, e.g. steel material, soil-pipe interaction and large rotations/displacements. 3-Dimensional FE Models permit to predict the overall pipeline global response under design loads taking into account the expected (during design phase) and/or actual (after measurements gathered during as-built survey campaign) 3-Dimensional pipeline configuration including 3-Dimensional (along and transversal to the pipeline route) bottom roughness, route bends, intervention works for bottom roughness and free-span correction and mitigation measures against HP/HT condition in operation. In this paper: • The design approach for HP/HT pipelines is described; • The main features of the ABAQUS FE Model, developed to predict the behavior of offshore pipelines in operation, are presented; • Two relevant examples of offshore pipelines subject to pressure and temperature conditions are presented with and without mitigation measures.


Author(s):  
Nitesh Sinha ◽  
Raj Kishore

With the ever-increasing demand of energy in the country, the Indian exploration and production is now compelled to move into deepwater frontiers. The country’s energy reserve is getting exhausted with drying shallow water assets and the mainland is already overwhelmed with the pressure of sustaining the world’s second largest population. Therefore, “the upstream oil and gas fraternity of the country” has to now enter “less explored” Indian deepwater block which has already started with the launch of the NELP block by the government. Although, the world has moved into deepwater long back, the Indian industry is still developing the ways and means to tackle the challenges involved in deep water. This paper presents the insights into design and installation of deepwater pipelines along with case study of Middle East to India Deepwater Pipeline (MEIDP) of M/s SAGE, which shall be laid at a maximum water depth of 3450 m. This paper broadly elucidates the challenges in designing the deepwater pipelines such as requirement of thick-walled line pipes to sustain collapse due to external over-pressure and tensile stresses generated due to installation forces, pipeline route selection and optimization, geo-hazard assessment & mitigation, design against fault line crossings/ seismic design, free span, repair systems, seabed intervention etc. It also covers the additional manufacturing & testing requirements including tighter tolerances for line pipes suitable for deepwater installations. It also highlights the deepwater installation capabilities of Pipe lay Barges for the laying of pipeline in the deepwater to ultra-deep waters along with new evolving testing and commissioning philosophies. This paper intends to bring awareness among the “oil and gas fraternity” regarding challenges involved in deep water pipelines with respect to design, installation etc.


Author(s):  
Fábio Arroyo ◽  
Rafael F. Solano ◽  
Luciano Mantovano ◽  
Fábio B. de Azevedo ◽  
Hélio Alves ◽  
...  

Large diameter UOE pipes are being increasingly used for the construction of offshore pipelines. Since oil discoveries are moving towards ultra-deepwater areas, such as Pre-Salt in Brazil, collapse resistance is a key factor in the design of the pipelines. It is known that the cold forming, and the final expansion in the UOE linepipe manufacturing process, reduces the elastic limit of the steel in subsequent compression. Due to this, the DNV collapse formula includes a fabrication factor that derates by a 15% the yield strength of UOE Pipes. However, DNV also recognizes the effect of thermal treatments and the code allows for improvement of the fabrication factor when heat treatment or external cold sizing (compression) is applied, if documented. This paper presents the qualification of UOE pipes with enhanced collapse capacity focusing the use of a fabrication factor (αfab) equal to 1. TenarisConfab has performed a technology qualification process according to DNV-RP-A203 standard “Qualification Procedures for New Technology”. The main aspects of the qualification process are presented in this paper which included significant material and full scale testing, including combine load testing, and final analysis. The qualification process achieved successful results and this will allow use of a fabrication factor equal to 1 directly in deepwater and ultra-deepwater offshore pipeline projects with a possible reduction in material and offshore installation costs and also potentially enhancing the feasibility of many challenging offshore projects.


Author(s):  
Lorenzo Maria Bartolini ◽  
Alberto Battistini ◽  
Lorenzo Marchionni ◽  
Antonio Parrella ◽  
Maurizio Spinazzè ◽  
...  

Future offshore pipelines development moves towards challenging operating condition and deep/ultra-deep water applications. Understanding the failure mechanisms and quantifying the strength and deformation capacity of pipelines, special components (buckle arrestors, wye, etc.) and in-line structures (in-line sled, in-line valve, in-line tee, etc.) is a need, under installation and operation loads, taking in account different geometrical characteristics and mechanical behaviors. The objective of this paper is to present and discuss recent FEM approaches integrating global and local analyses to evaluate the pipeline response and local effects, respectively. Thanks to this method the results coming from the global FEM analysis (main loads and driving phenomena) are used as input data for local FE Model with the aim to detect stress/strain intensification and other issues due to the local characteristics. In this paper: • The challenges of future deep water offshore pipelines are briefly presented; • The typical loading scenarios for pipelines during installation and operation are discussed; • The PipeONE 2014 tool, developed to facilitate the input/output data sharing between global and local FEM analyses, is presented and fully described in its main characteristics and capabilities; • An example is presented with the aim to understand and to appreciate the PipeONE 2014 functionality in FE modeling.


Author(s):  
Fábio Arroyo ◽  
Harold R. León ◽  
Ronaldo Silva ◽  
Luciano Mantovano ◽  
Rafael F. Solano ◽  
...  

Large diameter UOE pipes are being increasingly used for the construction of offshore pipelines and in the last few year, since oil discoveries are moving towards ultra-deepwater areas, such as Pre-Salt in Brazil, collapse resistance is a key factor in the design of the pipelines the demand for pipes with high thickness near the limits for fabrication and installation capacity. It is known that the cold forming, and the final expansion in the UOE line pipe manufacturing process, reduces the elastic limit of the steel in subsequent compression. Due to this, the DNV collapse formula includes a fabrication factor that de-rates by a 15% the yield strength of UOE Pipes. However, DNV also recognizes the effect of thermal treatments and the code allows for improvement of the fabrication factor when heat treatment or external cold sizing (compression) is applied, if documented. In previous work [1] it was presented the qualification of UOE pipes with enhanced collapse capacity focusing the use of a fabrication factor (alpha-fab) equal to 1. A technology qualification process according to international standard has been performed. The main aspects of the qualification process were presented and included significant material, full scale testing and final analysis. In this paper, we compare those results with the ones of the new qualification tests analyzing the more important variables affecting the collapse resistance such as ovality, compressive material strength, thermal treatment control, etc. This new qualification obtained even better results than the previous one, which will allow the use of a fabrication factor equal to 1 directly in deepwater and ultra-deepwater offshore pipeline projects with a possible reduction in material and offshore installation costs and also potentially enhancing the feasibility of many challenging offshore projects.


2010 ◽  
Vol 452-453 ◽  
pp. 689-692
Author(s):  
Jae Hyun Kim ◽  
Jung Yup Kim ◽  
Bong Kyun Jang ◽  
Kyung Shik Kim ◽  
Byung Ik Choi ◽  
...  

In this study, we propose a simplification scheme for modeling a complex bellows structure. Using 3-dimensional finite element analysis, vibration modes and natural frequencies are analyzed. The analysis results are compared with those measured by telemetry system of acceleration. It is found that bending mode of vibration can be activated even a low operation frequency and this leads to uneven distribution of stress. The uneven distribution of stress can be a possible cause for the early failure of a bellows with a large diameter.


Author(s):  
Lorenzo Maria Bartolini ◽  
Lorenzo Marchionni ◽  
Maurizio Spinazzè ◽  
Giulio Claudio Vignati ◽  
Luigino Vitali

In the last thirty years the attention of the offshore pipeline industry has been strongly focused on submarine pipelines crossing harsh environments and subject to severe operating conditions of temperature and pressure. Pipeline structural integrity may be threaten by large free-spanning sections between rocky peaks and deep depressions that may be coupled with the pipeline propensity to develop lateral/vertical deflection due to severe service conditions (high pressure/high temperature). For short flowlines, pipeline walking is an additional issue to be verified and faced during design and the application of an integrated approach between flow assurance, installation, geotechnics and pipeline design is a must. All these features characterize new load scenarios for which intervention works are mandatory to control the development of excessive loads and deformations within acceptance criteria. 3-Dimensional Finite Element Models permit to anticipate the pipeline global response under design loads taking into account the expected (during design phase) and/or actual (after measurements of the as-built) 3-Dimensional pipeline configuration. In case that mitigation measures are to be installed along the pipeline route, their effectiveness can be verified and optimized. Potential failure events in the most promising mitigation measure strategy can be investigated and anticipated at design stage. This paper describes the most relevant capability of the pre- and post-processing tools developed in MATLAB environment and based on ABAQUS Finite Element.


Author(s):  
Seung-Ho Yang ◽  
Jong-Jin Jung ◽  
Yun-Hak Kim ◽  
Woo-Seob Lee ◽  
Jong-Bae Kim

In recent years, requirement for the consideration of global buckling due to high pressure/high temperature (HP/HT) condition has increased in the detailed design of offshore pipelines on a seabed. The interaction between pipeline and seabed including support structures or sleepers gives a significant effect on buckling behavior. Global lateral buckling analysis has been carried out to assess the stability of offshore HP/HT pipelines considering the interaction between HP/HT submarine pipeline system/foundation structure and seabed. A non-linear finite element method is used in the present static analysis using the ABAQUS program. The FE model considers concrete sleepers as well as 3-D profile of the seabed. The stress distribution and lateral amplitude of the pipeline were evaluated and remedial measures were suggested to ensure that pipe stresses and strains are kept within allowable limits. Sleepers are designed as a buckle trigger which can provide artificial imperfection to allow pipe to move laterally and mitigate axial force. Comparative study could provide design strategy of pipeline related to sleeper supports.


2011 ◽  
Vol 368-373 ◽  
pp. 2711-2715 ◽  
Author(s):  
De Yun Ding ◽  
Xiu Ren Yang ◽  
Wei Dong Lu ◽  
Wei Ning Liu ◽  
Mei Yan ◽  
...  

In more and more complicated urban building environment, a new construction method that metro engineering is constructed by large-diameter shield and shallow mining method can be regarded as a great attempt in China. By taking the Gaojiayuan station of Beijing metro line 14 as an engineering background, the main construction steps for the platform of the metro station built by a large-size shield with an outer diameter of 10 m and the Pile-Beam-Arch (PBA) method are introduced. Based on the soil-structure interaction theory, a two-dimensional finite element model is used to simulate the shield tunneling and the platform construction by the PBA method to enlarge the shield tunnel. The ground deformation and structural stress of the platform are predicted. The numerical results can be regarded as a valuable reference for the application of the new construction method in Beijing metro line 14.


2020 ◽  
Vol 218 ◽  
pp. 108239
Author(s):  
Abhishek Ghosh Dastider ◽  
Neelanjan Sarkar ◽  
Santiram Chatterjee

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