Pipeline Integrity Assessment and Mitigation Techniques in Unstable Soil Conditions Based on Comparison of In Line Inspection Results

2013 ◽  
Author(s):  
Maria F. Contreras ◽  
Carlos Vergara ◽  
Mauricio Pereira ◽  
Juan Diego Colonia ◽  
Hugo García
Keyword(s):  
Oil And Gas ◽  
Soil Conditions ◽  
Finite Element Models ◽  
Integrity Assessment ◽  
The Andes ◽  
Bending Strain ◽  
Study Case ◽  
Mitigation Techniques ◽  
As Stress ◽  
Assessment And Mitigation Techniques

The Andes Mountains, rich in geographical features and diversity, poses a significant threat to the integrity of oil and gas pipelines due to geohazards. Land movement and unstable soil conditions can trigger changes in the original trajectory of the pipeline resulting in undesired bending strain which can result on failure of the facility. OCENSA – Oleoducto Central S.A. from Colombia assesses the pipeline condition in geotechnical unstable places by comparison of In Line inspection results taking into account pipeline movements and bending strains changes along the zone of study. Bending strains in the pipe are compared against allowable values and emergency values which constitute the criteria to execute mitigation and/or remediation activities that must be done in order to maintain the pipe integrity. To project the pipeline behavior in time, 3D finite element models are developed, allowing the programming of future activities. This paper presents results obtained in a study case to show how pipeline is assessed and how different mitigation activities are developed. Mitigation Techniques such as stress relief procedures and EPS (Expanded Poly-Styrene) blocks incorporations are explained. These techniques are executed in order to reduce the pipe response due to soil displacements during landslide events and creeping slopes, with the final scope of assuring a safe operation.

Strengthening Analysis on Tenon-Mortise Joint of a Face Beam in Tai-He Palace in the Forbidden City in China

2011 ◽  
Vol 255-260 ◽  
pp. 1597-1602
Author(s):  
Qian Zhou ◽  
Wei Ming Yan
Keyword(s):  
Finite Element ◽  
Composite System ◽  
Finite Element Models ◽  
Wood Composite ◽  
Stress Distributions ◽  
Element Simulation ◽  
The Face ◽  
As Stress ◽  
Strengthening Method ◽  
Cultural Relics

To protect Chinese ancient building,by theoretical calculation and finite element simulation sinkage as well as strengthening method on tenon-mortise joint of a face beam in Tai-He Palace in the Forbidden City were studied.2 strengthening methods were considered,by which calculation diagrams as well as finite element models for the beam were built and static analysis were carried out.Based on analysis results,displacement as well as stress distributions of the face beam before strengthened were obtained;Based on laws of cultural relics protection,the 2 strengthening methods were discussed and the more suitable one was selected.Results show that the main cause of sinkage of the face beam tenon relates closely to over great values of bending,tension as well as shearing stress values at the tenon-mortise joint position;The method that strengthening tenon-mortise joint by additional columns under the face beam may bring adverse effects to the substructure,however the method of using steel-wood composite system to strengthen the joint is more suitable which meets the demand of cultural relics protection.

The Failure Window Method and Its Application in Pipeline Burst

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Zhanfeng Chen ◽  
Hao Ye ◽  
Sunting Yan ◽  
Xiaoli Shen ◽  
Zhijiang Jin
Keyword(s):  
Internal Pressure ◽  
Maximum Stress ◽  
Oil And Gas ◽  
Maximum Shear Stress ◽  
High Accuracy ◽  
Burst Pressure ◽  
Empirical Equations ◽  
Integrity Assessment ◽  
Wall Thinning ◽  
Window Method

Accurate prediction of the burst pressure is indispensible for the engineering design and integrity assessment of the oil and gas pipelines. A plenty of analytical and empirical equations have been proposed to predict the burst pressures of the pipelines; however, it is difficult to accurately predict the burst pressures and evaluate the accuracy of these equations. In this paper, a failure window method was presented to predict the burst pressure of the pipes. First, the security of the steel pipelines under the internal pressure can be assessed. And then the accuracy of the previous analytical and empirical equations can also be generally evaluated. Finally, the effect of the wall thinning of the pipes on the failure window was systemically investigated. The results indicate that it is extremely formidable to establish an equation to predict the burst pressure with a high accuracy and a broad application, while it is feasible to create a failure window to determine the range of the dangerous internal pressure. Calculations reveal that some predictions of the burst pressure equations like Faupel, Soderberg, Maximum stress, and Nadai (1) are overestimated to some extent; some like ASME, maximum shear stress, Turner, Klever and Zhu–Leis and Baily–Nadai (2) basically reliable; the rest like API and Nadai (3) slightly conservative. With the wall thinning of the steel pipelines, the failure window is gradually lowered and narrowed.

scholarly journals Designing problems of oil fields infrustructre in the Arctic under the climate change

2021 ◽  
Vol 6 (3) ◽  
pp. 130-135
Author(s):  
Elena A. Poskonina ◽  
Anna N. Kurchatova
Keyword(s):  
Climate Change ◽  
Oil And Gas ◽  
Thermal Stabilization ◽  
Oil Fields ◽  
The Arctic ◽  
Soil Conditions ◽  
Industrial Facilities ◽  
Oil And Gas Fields ◽  
Gas Fields ◽  
Forecast Modeling

Background. Designing problems of oil fields infrastructure in the Arctic under climate change, namely, applying of temperature coefficient when calculating bearing capacity, heaving of lightly loaded foundations, optimization of thermal stabilization solutions are presented in the article. Aim. To change the strategy for designing foundations on permafrost by choosing the worst soil conditions to the implementation of an invariant matrix for designing and construction of soil bases and foundations considering specifics of industrial facilities of oil and gas fields based on unified numerical calculations (regulations). Materials and methods. An overview of the current regulatory requirements to the design of foundations on permafrost is made. The analysis of forecast modeling of the temperature of soil bases of typical industrial facilities of oil and gas fields to justify design solutions and also the use of thermal stabilization systems is done. Results. It is proposed to develop a regional directory of weather stations with long observation period based on updated climate data to decrease the volume of designing work and the amount of mistakes in applying of thermal stabilization systems. It is necessary to create regional dynamic models of permafrost geosystems, implement forecast modeling of seasonal thawing potential depth and frozen ground temperature in natural landscapes on the base of geotechnical monitoring data and select adaptation methods to existing or expecting climate change trends. Conclusions. Regulations on designing and construction of soil bases and foundations on permafrost considering specifics of industrial facilities of oil and gas fields is an effective solution. It allows moving on the strategy implementation of uniform approaches to oil fields development on permafrost: from designing for every structure on the base of typical solutions and results of engineering surveys to invariant matrix of project solutions.

Investigation of Strain-Based Failure Assessment Based on Reference Strain Method for Welded Pipes

2019 ◽  
Author(s):  
Jae Sung Lee ◽  
Myung Hyun Kim
Keyword(s):  
Reference Strain ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Effective Means ◽  
Equivalent Stress ◽  
Strain Curve ◽  
Evaluation Procedure ◽  
Element Analysis ◽  
Integrity Assessment ◽  
Strain Method

Abstract Pipelines are effective means to transport oil and gas. It is essential to maintain the safety of pipelines with the increasing demand for oil and gas resource. Welded pipelines may suffer damage such as cracks during installation and operation, and the consequence evaluation for such damage is very important. Engineering critical assessment (ECA) is the evaluation procedure for structures with flaws and has been widely applied for assessing the pipeline integrity. Although main standards of structural integrity assessment including BS 7910 are stress-based ECA, it is known to produce overly conservative results. In this regard, strain-based ECA has been recently developed. One of the methods for improving the accuracy of strain-based ECA is the reference strain method. However, only few researches with reference strain method applied to welded pipes are available. Therefore, in this study, a numerical analysis based on the strain-based ECA is performed for strength mismatched girth welded joints with a circumferentially oriented internal surface crack. Equivalent stress-strain curve in BS7910 is employed to reflect the strength mismatch effects in the reference strain. This paper compares the results from the reference strain method and finite element analysis: J-integral and reference strain. Strain capacity of the reference strain method with strength mismatch is also discussed against stress-based ECA.

Integrity Assessment of Multiple Dents in Oil and Gas Pipelines Using Probabilistic Design Analysis

2010 ◽  
Author(s):  
Husain Mohammed Al-Muslim ◽  
Abul Fazal M. Arif
Keyword(s):  
Oil And Gas ◽  
Mechanical Damage ◽  
Pipe Material ◽  
Probabilistic Design ◽  
Gas Pipelines ◽  
Pressure Loading ◽  
Integrity Assessment ◽  
Oil And Gas Pipelines ◽  
Input Parameters ◽  
Pipe Geometry

Mechanical damage in transportation pipelines is a threat to its structural integrity. Failure in oil and gas pipelines is catastrophic as it leads to personal fatalities, injuries, property damage, loss of production and environmental pollution. Therefore, this issue is of extreme importance to Pipeline Operators, Government and Regulatory Agencies, and local Communities. As mechanical damage can occur during the course of pipeline life due to many reasons, appropriate tools and procedures for assessment of severity are necessary. There are many parameters that affect the severity of the mechanical damage related to the pipe geometry and material properties, the defect geometry and boundary conditions, and the pipe state of strain and stress. Moreover, multiple damaged areas may exist and interact like in the case of a hit by a multiple-tooth excavator. The main objective of this paper is to determine the distance and orientation where interaction of multiple dents is significant. The strain and stress fields are evaluated for static pressure loading and the stress range and fatigue life are evaluated for cyclic pressure loading. Accordingly, guidelines are developed for the integrity assessment of multiple dents in oil and gas pipelines. The input parameters of the problem including the pipe material, pipe geometry, dent dimensions, and distance and orientation between two dents have a great variability. Therefore, probabilistic design approach is applied to determine the sensitivity and correlation between the output and input parameters. The base case deterministic FEA model has been validated with full-instrumented full-scale tests conducted by Pipeline Research Council International as part of their active program to fully characterize mechanical damage.

scholarly journals Modeling and Calculation of Dent Based on Pipeline Bending Strain

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Qingshan Feng ◽  
Rui Li ◽  
Hong Zhang
Keyword(s):  
Inertial Measurement Unit ◽  
Oil And Gas ◽  
Measurement Unit ◽  
Mapping Data ◽  
Long Distance ◽  
Bending Strain ◽  
Strain Data ◽  
Integrity Management ◽  
Novel Method ◽  
The Mean

The bending strain of long-distance oil and gas pipelines can be calculated by the in-line inspection tool which used inertial measurement unit (IMU). The bending strain is used to evaluate the strain and displacement of the pipeline. During the bending strain inspection, the dent existing in the pipeline can affect the bending strain data as well. This paper presents a novel method to model and calculate the pipeline dent based on the bending strain. The technique takes inertial mapping data from in-line inspection and calculates depth of dent in the pipeline using Bayesian statistical theory and neural network. To verify accuracy of the proposed method, an in-line inspection tool is used to inspect pipeline to gather data. The calculation of dent shows the method is accurate for the dent, and the mean relative error is 2.44%. The new method provides not only strain of the pipeline dent but also the depth of dent. It is more benefit for integrity management of pipeline for the safety of the pipeline.

scholarly journals Pipeline Bending Strain Measurement and Compensation Technology Based on Wavelet Neural Network

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Rui Li ◽  
Maolin Cai ◽  
Yan Shi ◽  
Qingshan Feng ◽  
Shucong Liu ◽  
...  
Keyword(s):  
Neural Network ◽  
Oil And Gas ◽  
Original Method ◽  
Wavelet Neural Network ◽  
Measurement Unit ◽  
Gas Pipelines ◽  
Long Distance ◽  
Pipeline Inspection ◽  
Bending Strain ◽  
Oil And Gas Pipelines

The bending strain of long distance oil and gas pipelines may lead to instability of the pipeline and failure of materials, which seriously deteriorates the transportation security of oil and gas. To locate the position of the bending strain for maintenance, an Inertial Measurement Unit (IMU) is usually adopted in a Pipeline Inspection Gauge (PIG). The attitude data of the IMU is usually acquired to calculate the bending strain in the pipe. However, because of the vibrations in the pipeline and other system noises, the resulting bending strain calculations may be incorrect. To improve the measurement precision, a method, based on wavelet neural network, was proposed. To test the proposed method experimentally, a PIG with the proposed method is used to detect a straight pipeline. It can be obtained that the proposed method has a better repeatability and convergence than the original method. Furthermore, the new method is more accurate than the original method and the accuracy of bending strain is raised by about 23% compared to original method. This paper provides a novel method for precisely inspecting bending strain of long distance oil and gas pipelines and lays a foundation for improving the precision of inspection of bending strain of long distance oil and gas pipelines.

Status of Fitness-for-Service Assessment of Defected Pipeline in China

2007 ◽  
Author(s):  
Xinwei Zhao ◽  
Jinheng Luo ◽  
Baosheng Dong ◽  
Hua Zhang ◽  
Guangli Zhang
Keyword(s):  
Residual Strength ◽  
Life Prediction ◽  
Oil And Gas ◽  
Gas Pipeline ◽  
Assessment Criteria ◽  
Remaining Life ◽  
Strength Evaluation ◽  
Integrity Assessment ◽  
Research Status ◽  
Key Technologies

Fitness-for-service assessment of defected pipeline is an important part of oil and gas pipeline integrity assessment and management. Fitness-for-service assessment comprises a residual strength evaluation and a remaining life prediction for a damaged pipeline. In the present paper, the objectives and methods for fitness-for-service assessment are classified scientifically, and their worldwide research status has been reviewed. Several novel fitness-for-service assessment criteria proposed in China are presented. Challenging problems and key technologies for fitness-for-service assessment of pipelines are outlined.

scholarly journals Decoupled recovery of ecological communities after reclamation

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7038 ◽  
Author(s):  
Zachary A. Sylvain ◽  
David H. Branson ◽  
Tatyana A. Rand ◽  
Natalie M. West ◽  
Erin K. Espeland
Keyword(s):  
Plant Species ◽  
Plant Communities ◽  
Oil And Gas ◽  
Plant Cover ◽  
Reference Conditions ◽  
Soil Conditions ◽  
Ecological Communities ◽  
Native Plant ◽  
Ecosystem Recovery ◽  
Nematode Communities

Grassland restoration is largely focused on creating plant communities that match reference conditions. However, these communities reflect only a subset of the biodiversity of grassland systems. We conducted a multi-trophic study to assess ecosystem recovery following energy development for oil and gas extraction in northern US Great Plains rangelands. We compared soil factors, plant species composition and cover, and nematode trophic structuring between reclaimed oil and gas well sites (“reclaims”) that comprise a chronosequence of two—33 years since reclamation and adjacent, undeveloped rangeland at distances of 50 m and 150 m from reclaim edges. Soils and plant communities in reclaims did not match those on undeveloped rangeland even after 33 years. Reclaimed soils had higher salt concentrations and pH than undeveloped soils. Reclaims had lower overall plant cover, a greater proportion of exotic and ruderal plant cover and lower native plant species richness than undeveloped rangeland. However, nematode communities appear to have recovered following reclamation. Although total and omni-carnivorous nematode abundances differed between reclaimed well sites and undeveloped rangeland, community composition and structure did not. These findings suggest that current reclamation practices recover the functional composition of nematode communities, but not soil conditions or plant communities. Our results show that plant communities have failed to recover through reclamation: high soil salinity may create a persistent impediment to native plant growth and ecosystem recovery.

scholarly journals Comparative Study of Structural Reliability Assessment Methods for Fixed Offshore Structures

2021 ◽  
Author(s):  
E. Mat Soom ◽  
M.K. Abu Husain ◽  
N.I. Mohd Zaki ◽  
N.A. Mukhlas ◽  
S.Z.A. Syed Ahmad ◽  
...  
Keyword(s):  
Structural Reliability ◽  
Oil And Gas ◽  
Offshore Structures ◽  
Mitigation Strategies ◽  
Life Extension ◽  
Risk Level ◽  
Long Distance ◽  
Design Assessment ◽  
Integrity Assessment ◽  
Structural Deterioration

The oil and gas sector has recognised structural integrity assessment of ageing platform for prospective life extension as a rising concern, particularly in encountering the randomness of the harsh ocean environments. This condition leads to uncertainty in wave-in-deck load estimates and a high load level being imposed on offshore structures. This emphasises the necessity of enhanced reliability, as failure might result in inaccessibility because of the uncertainties related to long-distance services, such as accuracy of predictions of loads and responses. Even though the established guidelines present a fundamental assessment, additionally, comprehensive rules are required. This paper performed a reliability analysis incorporating practical approaches that can more accurately represent time-dependent structural deterioration. The following two procedures have been adopted by a majority of significant oil and gas operators to monitor the safety and integrity of these structures: a) Ultimate Strength Assessment (USA) method and b) Reliability Design Assessment (ReDA) method. A comparison of these two reliability approaches was performed on selected ageing jacket structures in the region of the Malaysian sea. The comparative findings, namely, reserve strength ratio (RSR) at various years of the return period (RP) and ratio value for risk of failure regarding the probability of failure (POF), provided a check and balance in strengthening confidence in the results. The findings showed that the structural components might safely survive either using the USA and ReDA method in such conditions, as the reliability indexes were determined to be satisfactory compared to allowable values from ISO 19902 design specifications. Therefore, these evaluations were determined to control the risk level of the structure during the remaining of its lifetime and undertake cost-effective inspections or mitigation strategies when necessary.

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