Wellhead Fatigue Analysis Method

2011 ◽  
Author(s):  
Lorents Reina˚s ◽  
Torfinn Ho̸rte ◽  
Morten Sæther ◽  
Guttorm Gryto̸yr
Keyword(s):  
Fatigue Damage ◽  
Fatigue Analysis ◽  
Response Analysis ◽  
Analysis Method ◽  
Drilling Rig ◽  
Analysis Methodology ◽  
Well Integrity ◽  
Stress Curve ◽  
Integrity Management ◽  
Load Analysis

Re-completion and re-drilling of existing wells and introduction of new large drilling rig systems are elements that have led to renewed focus on the fatigue capacity for existing and new subsea wells. Due to lack of applicable codes and standards for such fatigue calculations, a unified analysis methodology has been developed and described in a Wellhead Fatigue Analysis Method Statement (MS). The intention of this work is to reflect the best practice in the industry and to provide an important contribution to well integrity management. The analysis methodology is limited to fatigue damage from dynamic riser loads present during subsea drilling and work over operations. The analysis procedure may be divided into three parts. i) A local response analysis that includes a detailed finite element model from wellhead datum and below. Interaction between the structural well components and soil structure interaction is properly accounted for. The main result from this analysis is the load-to-stress curve that describes the relationship between the riser loads at the wellhead datum and the stress at the fatigue hot spots. The analysis also provides the lower boundary conditions of the global load analysis model. ii) A global load analysis where the floating mobile drilling unit (MODU) motions and wave loads on the riser are taken into account. The results are time series or load histograms of the loads at wellhead datum, with focus on the bending moment, in all relevant environmental sea states. iii) Fatigue damage assessment, where a mapping of the loads with the relevant load to stress curve is carried out together with subsequent fatigue damage calculation. Appropriate S-N curve is applied together with wave scatter diagrams for the relevant operations and durations. The final result is the accumulated fatigue damage. With a unified analysis methodology in place particular attention is placed on a structured and specified analysis input and output. Results are suggested presented as a function of time and also as a function of key analysis input parameters that are associated with uncertainty. These are prerequisites from a well integrity management perspective in ensuring analysis results that are comparable. This paper presents the essence of the Wellhead Fatigue Analysis Method that was developed in cooperation between Statoil and DNV. Currently this analysis methodology is under extension and revision in the joint industry project (JIP) “Structural Well Integrity During Well Operations”. 11 operators participate in this JIP which also has structured cooperation with equipment suppliers, drilling companies and analysis houses. The aim is to form a wellhead analysis recommended practice document.

Wellhead Fatigue Analysis Method: The Effect of Variation of Lower Boundary Conditions in Global Riser Load Analysis

2012 ◽  
Author(s):  
Lorents Reinås ◽  
Massimiliano Russo ◽  
Guttorm Grytøyr
Keyword(s):  
Boundary Condition ◽  
Boundary Conditions ◽  
Lower Boundary ◽  
Fatigue Analysis ◽  
Analysis Model ◽  
Lower Boundary Condition ◽  
Analysis Methodology ◽  
Well Integrity ◽  
Context Modelling ◽  
Load Analysis

Subsea wellhead mechanical fatigue can potentially result in a gross structural failure of barrier elements in the upper part of the well, potentially resulting in loss of well control. Several major E&P operators have acknowledged the importance of wellhead fatigue and are participating in the JIP “Structural Well Integrity”. It is within the scope of this JIP to develop a recommended practice for wellhead fatigue analysis methodology. The analysis methodology currently being investigated by the JIP is a decoupled approach, with modifications of the lower boundary to account for the stiffness of the conductor, soil and template interface. A detailed local wellhead model is used to generate the lower boundary condition for a decoupled global riser load analysis model. This lower boundary condition definition is intended to capture the overall non-linear stiffness of a site specific well in order to achieve best possible global riser loads estimate. In this article the effect of varying the lower boundary conditions on a global load estimate is studied. Global load estimates are generated from a typical North Sea case and various lower boundary conditions are introduced as the only change to the global riser model. A fixed lower boundary condition is used as a reference and load estimates generated from riser models with various lower boundary conditions are compared. The different lower boundary conditions selected for comparison in this study has been derived from the following cases: 1. Fixed at WH 2. As per ISO 13624-2 3. As per JIP “Structural Well Integrity” -Current 4. As per JIP “Structural Well Integrity” -Modified Comparing the analysis results gives indications that the lower boundary condition modelling approach affect global riser load estimate. The fixed lower end boundary conditions did not yielded the most conservative load history in a fatigue context. Modelling well specific flexibility at the riser lower end increased the total number of wellhead fatigue load cycles. This finding support the current approach suggested by the works of the JIP “Structural Well Integrity”. Ensuring that riser load results are still conservative places a higher importance on precise local modelling of the well system.

Hybrid Fatigue Analysis Method for Railway Carbody Structure

2008 ◽  
Vol 44-46 ◽  
pp. 733-738 ◽  
Author(s):  
Bing Rong Miao ◽  
Wei Hua Zhang ◽  
Shou Ne Xiao ◽  
Ding Chang Jin ◽  
Yong Xiang Zhao
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Hybrid Method ◽  
Dynamic Stress ◽  
Stress Test ◽  
Fatigue Analysis ◽  
Railway Vehicle ◽  
Analysis Method ◽  
Structure Dynamic ◽  
Multi Body

Railway vehicle structure fatigue life consumption monitoring can be used to determine fatigue damage by directly or indirectly monitoring the loads placed on critical vehicle components susceptible to failure from fatigue damage. The sample locomotive carbody structure was used for this study. Firstly, the hybrid fatigue analysis method was used with Multi-Body System (MBS) simulation and Finite Element Method (FEM) for evaluating the carbody structure dynamic stress histories. Secondly, the standard fatigue time domain method was used in fatigue analysis software FE-FATIGUE and MATLAB WAFO (Wave Analysis for Fatigue and Oceanography) tools. And carbody structure fatigue life and fatigue damage were predicted. Finally, and carbody structure dynamic stress experimental data was taken from this locomotive running between Kunming-Weishe for this analysis. The data was used to validate the simulation results based on hybrid method. The analysis results show that the hybrid method prediction error is approximately 30.7%. It also illustrates that the fatigue life and durability of the locomotive can be predicted with this hybrid method. The results of this study can be modified to be representative of the railway vehicle dynamic stress test.

In situ and experimental analysis of longitudinal load on carbody fatigue life using nonlinear damage accumulation

2021 ◽  
pp. 105678952110460
Author(s):  
Sunil Kumar Sharma ◽  
Rakesh Chandmal Sharma ◽  
Jaesun Lee
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
Damage Accumulation ◽  
Dynamic Stress ◽  
Fatigue Analysis ◽  
Analysis Method ◽  
Accumulation Model ◽  
Longitudinal Load ◽  
Damage Accumulation Model

In this paper, a multi-disciplinary analysis method is proposed for evaluating the fatigue life of railway vehicle car body structure under random dynamic loads. Firstly, the hybrid fatigue analysis method was used with Multi-Body System simulation and finite element method for evaluating the carbody structure dynamic stress histories. The dynamics stress is calculated from the longitudinal load using longitudinal train dynamics. Secondly, the nonlinear damage accumulation model was used in fatigue analysis, and carbody structure fatigue life and fatigue damage were predicted. The mathematical model simulations are compared with results produced experimentally, showing good agreement. Finally, the mode is determined after the finite element model is established. To achieve the dynamic stress at each node, the modal response is used as excitation. The carbody damage was obtained by combining dynamics stress with the NMCCMF damage accumulation model. As a result, the effect of longitudinal load on carbody fatigue damage is investigated. The longitudinal load contributes significantly to the fatigue damage of the carbody.

Pathway to Evaluate Printed Circuit Heat Exchanger Based on Simplified Elastic-Perfectly Plastic Analysis Methodology for High Temperature Nuclear Service

2019 ◽  
Author(s):  
Urmi Devi ◽  
Machel Morrison ◽  
Tasnim Hassan
Keyword(s):  
High Temperature ◽  
Fatigue Damage ◽  
Analysis Method ◽  
Printed Circuit ◽  
Perfectly Plastic ◽  
Analysis Methodology ◽  
Inelastic Analysis ◽  
Creep Fatigue ◽  
Asme Code ◽  
Elastic Perfectly Plastic

Abstract Printed Circuit Heat Exchangers (PCHEs) are well-suited for Very High Temperature Reactors (VHTRs) due to high compactness and efficiency for heat transfer. The design of PCHE must be robust enough to withstand possible failure caused by cyclic loading during high temperature operation. The current rules in ASME Code Section III Division 5 to evaluate strain limits and creep-fatigue damage based on elastic analysis method have been deemed infeasible at temperatures above 650°C. Hence, these rules are inapplicable for temperatures ranging from 760–950°C for VHTRs. A full inelastic analysis method with complex constitutive material description as an alternative, on the other hand, is time consuming; hence impracticable. Therefore, the simplified Elastic-Perfectly Plastic (EPP) analysis methodology is used as a solution in ASME Code Section III Division 5. The current literature, however, lacks any study on the performance evaluation of PCHE through EPP analysis. To address these issues, this study initiates the pathway of EPP evaluation of an actual size PCHE starting with elastic orthotropic analysis in the global scale. Subsequently, preliminary planning for analyzing intermediate and local submodels are provided to determine channel level responses to evaluate PCHE performance against strain limits and creep-fatigue damage using Code Case-N861 and N862 respectively.

Fatigue Analysis of Multi-Spanning Subsea Pipeline

2010 ◽  
Author(s):  
Kosar Rezazadeh ◽  
Liyun Zhu ◽  
Yong Bai ◽  
Liang Zhang
Keyword(s):  
Stress Distribution ◽  
Dynamic Analysis ◽  
Static Analysis ◽  
Fatigue Analysis ◽  
Sensitivity Analyses ◽  
Fe Model ◽  
Analysis Method ◽  
Subsea Pipeline ◽  
Interaction Control ◽  
Integrity Management

Free-span occurs normally in pipeline at uneven seabed, dynamic seabed or pipeline crossing. The analysis of free-span, including static analysis and dynamic analysis, is an important subject in the study of pipeline integrity management. Static analysis of free span for subsea pipeline is to evaluate the stress distribution of spanning pipeline in the ultimate conditions, and qualify the stress with design codes in the engineering analysis. However, dynamic analysis of subsea spanning pipeline is much complicated due to VIV fatigue. In 2006 DNV-RP-F105 suggested a methodology of dynamic analysis for long spanning pipeline with multi-mode responses, but the fatigue analysis method for multi-modes is not detailed. In addition, the fatigue analysis of multi-spanning pipeline is not clear. The gap between the continuous two spans, and the pipe-soil interaction control the fatigue damage of the multi-spanning pipeline. In this paper, a VIV fatigue analysis method for multi-spanning pipeline is suggested based on VIV analysis. In this method, Abaqus FE model is developed first to obtain the stress distribution and the natural frequency of each vibration mode for spanning pipeline on seabed in different configurations with three multi-spans, and then the fatigue analysis of VIV is carried out for the spanning pipeline based on DNV-RP-F105. An example of fatigue analysis for a multi-spanning pipeline is presented; finally, several sensitivity analyses demonstrate the effects of key parameters on the VIV fatigue.

An Expert Software System has Accomplished Full Implementation of Well Integrity Management System WIMS Resulting to Excellent Safety and Production Sustainability for Critical Sour HPHT Field in Offshore Madura Strait, Indonesia

2021 ◽  
Author(s):  
Fianti Ramadhani ◽  
Syaiful Nurdin ◽  
Michael Olu Etuhoko ◽  
Yang Zhi ◽  
Sugeng Mulyono ◽  
...  
Keyword(s):  
Management System ◽  
Material Selection ◽  
International Standards ◽  
Software System ◽  
Well Performance ◽  
Integrity Test ◽  
Well Integrity ◽  
High Pressure High Temperature ◽  
Integrity Management ◽  
Productive Assets

Abstract Four high-pressure-high temperature (HPHT) and sour gas wells are currently operating at Madura offshore as the only productive assets for Husky-CNOOC Madura Limited (HCML). Each well performance is very crucial to fulfill the demand of the gas customers in East Java, Indonesia. Since starting production in 2017, the wells experienced two main well integrity challenges, high annulus pressure and wellhead growth. Both challenges are very dependent to the well flow rate and the flow duration. A continuous operation monitoring is highly required in order to keep the wells operating safely. To overcome the challenges, HCML established a Well Integrity Management System (WIMS) document that approached several international standards as its basis. As company grows, development plan challenged the WIMS to perform faster and more efficient as compared to the existing manual system. From there, the journey of WIMS digitalization began. The journey started with the alignment of the existing WIMS document to the ISO-16530-1 at Operational Phase with more stringent boundary to operate the wells safely. The alignment covers, but not limited to the organizational structure, well barriers and criteria, monitoring and surveillance, annulus pressure management, and maintenance. The document also covered risk assessment and management of well integrity failure, which was the backbone of the WIMS digitalization. The current digital solutions allow production data to be accessed and retrieved directly from the system for analysis purposes. It compares the recorded data with pre-determined rules and parameters set in the system. It triggers a notification to the responsible personnel to perform the required action should any anomaly occurs. It also can send a reminder to users to schedule and complete a well Integrity test to ensure that a well is always in compliance with the WIMS. All test reports and documentation are stored in the system as preparation for any future audit. A key requirement of the expert software system was access to future developments that can offer enhanced functionality of the well integrity platform through additional near time capabilities such as predictive erosion and corrosion for downhole flow wetted components. This is being developed to enhance workover scheduling for existing wells and material selection for new wells and is planned to update automatically critical well integrity criteria such as tubing burst, collapse and MAASP.

scholarly journals Escalation of Turkey-Syria conflict in Idlib in February–March 2020: based on the results of event analysis.

2021 ◽  
pp. 18-38
Author(s):  
Daniil Andreevich Phedotov ◽  
Maksim Yuryevich Shcheglov
Keyword(s):  
Event Analysis ◽  
Analysis Method ◽  
Military Operation ◽  
Development Stages ◽  
Analysis Methodology ◽  
The Subject ◽  
Media Reports ◽  
Frozen Conflict

The subject of this research is the escalation of Turkey-Syria conflict in February–March 2020. The authors explore the prerequisites of the conflict, development stages, escalation factors, and consequences of confrontation. Description is given to the positions of the three opposing actors: Syrian-Russian, Turkish, and NATO bloc. The methodology of event analysis methodology is applied to the conflict. Emphasis is placed on the course of events reflected in charts. Use of the method of event analysis allows tracing the key vectors and their intersection: escalation – peacemaking. The author employs media reports of all parties to the conflict for demonstrating the peculiarities of escalation of the confrontation. The novelty lies in application of the method of event analysis method for assessing the specifics of escalation of the Spring Shield military operation in the conditions of modern hybrid warm, which provides different perspectives on the conflict. The conclusion is made on interaction of the actors and their impact upon escalation and peacemaking. It is established that Syria and Turkey exerted major impact upon escalation of the conflict, while Russia acted as the arbiter and the main force of moderation. Conflict potential of the Idlib crisis remains high and characterized as protracted semi-frozen conflict.

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