Oil and Gas Pipeline Residual Strength Research Based on Reliability Analysis

2013 ◽  
Vol 318 ◽  
pp. 562-566 ◽  
Author(s):  
Xian Yong Zhang ◽  
Jin Feng
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Monte Carlo ◽  
Wall Thickness ◽  
Oil And Gas ◽  
Safety Evaluation ◽  
Residual Value ◽  
Defect Depth ◽  
X80 Steel ◽  
Pipeline Safety

Strength of residual wall thickness reliability was studied by Monte-Carlo and finite element method, based on 40in X70 steel and 48in X80 steel which were often used in oil and gas transport pipeline. Pipe with defects in different residual wall thinkness, calculated the critical residual value of wall thickness, and analysed the defect depth and width of influence on pipe reliability. The results provide basis for pipeline safety evaluation and reasonable replacement.

Stress Analysis of Hollow Proppant Based on Finite Element Method

2019 ◽  
Vol 944 ◽  
pp. 1094-1102
Author(s):  
Xiao Gang Li ◽  
Zi Jia Liao ◽  
Zhao Zhong Yang ◽  
Jun Ya Xiong ◽  
Yu Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wall Thickness ◽  
Oil And Gas ◽  
Hollow Structure ◽  
Gas Reservoir ◽  
Reservoir Stimulation ◽  
Fracturing Process ◽  
Oil And Gas Reservoir ◽  
Element Method

Proppant is a key material used to support underground fractures in oil and gas reservoir stimulation. At present, the density of most proppant is so large that the settle velocity is fast, which lead to the poor transportability in the fracturing process. The ideal proppant should have a lower density, such as hollow proppant. The hollow structure reduces the proppant density, improving the proppant transportability, but affects the proppant other performances such as strength and hardness. In order to improve the problem, it is necessary to optimize the hollow structure. This paper briefly introduces the hollow proppant, and uses the finite element method to analyze the stress characteristics of proppant with different hollow radius and wall thickness. The effect of hollow structure on the proppant density, strength and hardness is discussed. The results show that: (1) the density of hollow proppant is mainly influenced by the hollow radius, (2) the stress characteristic of hollow proppant is different from solid proppant, (3) the strength of hollow proppant increases with the increase of wall thickness and hollow radius, (4) the embedded depth of hollow proppant shows linear positive correlation with the proppant size.

Reliability Analysis of Wear Casing Internal Pressure Strength

2013 ◽  
Vol 652-654 ◽  
pp. 1362-1366 ◽  
Author(s):  
Xian Yong Zhang ◽  
Jin Feng
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Monte Carlo ◽  
Internal Pressure ◽  
Reliability Analysis ◽  
Safety Evaluation ◽  
Steel Grade ◽  
Wear Depth ◽  
P110 Steel ◽  
Internal Pressures

Reliability of eccentric wear casing was studied by Monte-Carlo and finite element method. In different internal pressures, calculated reliability of P110 steel grade 9 5/8 inches casing with wear depth less than 0.5 times wall thickness. The influence of different cement ring circumferential missing amount and stratum pressures on wear casing reliability were presented. The results provide basis for casing safety evaluation and reasonable replacement.

Based on ANASYS with Finite Element Analysis and Calculation of Cracked Pipeline

2014 ◽  
Vol 989-994 ◽  
pp. 3185-3188
Author(s):  
Xiu Mei Zhu ◽  
Yu Ping Lv
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Corrosion ◽  
Stress Corrosion Crack ◽  
Oil And Gas ◽  
Safety Evaluation ◽  
Transportation Industry ◽  
Ansys Software ◽  
Element Analysis

Pipeline in the entire oil and gas transportation industry play an important role and in the soil is corroded in order to produce the stress corrosion crack. The topic analyzes and calculates cracked pipeline with finite element method by use of ANSYS software mainly, and provides the theory basis for safety evaluation of pipeline.

scholarly journals MDFEM: Multivariate decomposition finite element method for elliptic PDEs with lognormal diffusion coefficients using higher-order QMC and FEM

2021 ◽  
Author(s):  
Dong T.P. Nguyen ◽  
Dirk Nuyens
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Monte Carlo ◽  
Convergence Rates ◽  
Higher Order ◽  
Elliptic Pdes ◽  
Infinite Dimensional ◽  
Quasi Monte Carlo ◽  
Higher Order Convergence ◽  
Element Method

We introduce the \emph{multivariate decomposition finite element method} (MDFEM) for elliptic PDEs with lognormal diffusion coefficients, that is, when the diffusion coefficient has the form $a=\exp(Z)$ where $Z$ is a Gaussian random field defined by an infinite series expansion $Z(\bsy) = \sum_{j \ge 1} y_j \, \phi_j$ with $y_j \sim \calN(0,1)$ and a given sequence of functions $\{\phi_j\}_{j \ge 1}$. We use the MDFEM to approximate the expected value of a linear functional of the solution of the PDE which is an infinite-dimensional integral over the parameter space. The proposed algorithm uses the \emph{multivariate decomposition method} (MDM) to compute the infinite-dimensional integral by a decomposition into finite-dimensional integrals, which we resolve using \emph{quasi-Monte Carlo} (QMC) methods, and for which we use the \emph{finite element method} (FEM) to solve different instances of the PDE.   We develop higher-order quasi-Monte Carlo rules for integration over the finite-di\-men\-si\-onal Euclidean space with respect to the Gaussian distribution by use of a truncation strategy. By linear transformations of interlaced polynomial lattice rules from the unit cube to a multivariate box of the Euclidean space we achieve higher-order convergence rates for functions belonging to a class of \emph{anchored Gaussian Sobolev spaces} while taking into account the truncation error. These cubature rules are then used in the MDFEM algorithm.   Under appropriate conditions, the MDFEM achieves higher-order convergence rates in term of error versus cost, i.e., to achieve an accuracy of $O(\epsilon)$ the computational cost is $O(\epsilon^{-1/\lambda-\dd/\lambda}) = O(\epsilon^{-(p^* + \dd/\tau)/(1-p^*)})$ where $\epsilon^{-1/\lambda}$ and $\epsilon^{-\dd/\lambda}$ are respectively the cost of the quasi-Monte Carlo cubature and the finite element approximations, with $\dd = d \, (1+\ddelta)$ for some $\ddelta \ge 0$ and $d$ the physical dimension, and $0 < p^* \le (2 + \dd/\tau)^{-1}$ is a parameter representing the sparsity of $\{\phi_j\}_{j \ge 1}$.

scholarly journals Monte Carlo Simulation for Exploring Mechanical Properties of Porous Materials Based on Scaled Boundary Finite Element Method

2022 ◽  
Vol 12 (2) ◽  
pp. 575
Author(s):  
Guangying Liu ◽  
Ran Guo ◽  
Kuiyu Zhao ◽  
Runjie Wang
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Monte Carlo Simulation ◽  
Finite Element ◽  
Monte Carlo ◽  
Porous Materials ◽  
Influencing Factors ◽  
Random Models ◽  
Scaled Boundary Finite Element ◽  
Element Method

The existence of pores is a very common feature of nature and of human life, but the existence of pores will alter the mechanical properties of the material. Therefore, it is very important to study the impact of different influencing factors on the mechanical properties of porous materials and to use the law of change in mechanical properties of porous materials for our daily lives. The SBFEM (scaled boundary finite element method) method is used in this paper to calculate a large number of random models of porous materials derived from Matlab code. Multiple influencing factors can be present in these random models. Based on the Monte Carlo simulation, after a large number of model calculations were carried out, the results of the calculations were analyzed statistically in order to determine the variation law of the mechanical properties of porous materials. Moreover, this paper gives fitting formulas for the mechanical properties of different materials. This is very useful for researchers estimating the mechanical properties of porous materials in advance.

Failure Pressure Prediction of Cracks in Corrosion Defects Using XFEM

2020 ◽  
Author(s):  
Xinfang Zhang ◽  
Allan Okodi ◽  
Leichuan Tan ◽  
Juliana Leung ◽  
Samer Adeeb
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Extended Finite Element Method ◽  
Crack Depth ◽  
Average Error ◽  
Extended Finite Element ◽  
Defect Depth ◽  
Failure Pressure ◽  
Corrosion Defects ◽  
Element Method

Abstract Coating and cathodic protection degradation can result in the generation of several types of flaws in pipelines. With the increasing number of aging pipelines, such defects can constitute serious concerns for pipeline integrity. When flaws are detected in pipelines, it is extremely important to have an accurate assessment of the associated failure pressure, which would inform the appropriate remediation decision of repairing or replacing the defected pipelines in a timely manner. Cracks-in-corrosion (CIC) represent a class of defect, for which there are no agreed upon method of assessment, with no existing analytical or numerical models to predict their failure pressures. This paper aims to create a set of validated numerical finite element analysis models that are suitable for accurately predicting the failure pressure of 3D cracks-in-corrosion defects using the eXtended Finite Element Method (XFEM) technique. The XFEM for this study was performed using the commercially available software package, ABAQUS Version 6.19. Five burst tests of API 5L X60 specimens with different defect depths (varying from 52% to 66%) that are available in the literature were used to calibrate the XFEM damage parameters (the maximum principal strain and the fracture energy). These parameters were varied until a reasonable match between the numerical results and the experimental measurements was achieved. Symmetry was used to reduce the computation time. A longitudinally oriented CIC defect was placed at the exterior of the pipe. The profile of the corroded area was assumed to be semi-elliptical. The pressure was monotonically increased in the XFEM model until the crack or damage reached the inner surface of the pipe. The results showed that the extended finite element predictions were in good agreement with the experimental data, with an average error of 5.87%, which was less conservative than the reported finite element method predictions with an average error of 17.4%. Six more CIC models with the same pipe dimension but different crack depths were constructed, in order to investigate the relationship between crack depth and the failure pressure. It was found that the failure pressure decreased with increasing crack depth; when the crack depth exceeded 75% of the total defect depth, the CIC defect could be treated as crack-only defects, since the failure pressure for the CIC model approaches that for the crack-only model for ratios of the crack depth to the total defect depth of 0.75 and 1. The versatility of several existing analytical methods (RSTRENG, LPC and CorLAS) in predicting the failure pressure was also discussed. For the corrosion-only defects, the LPC method predicted the closest failure pressure to that obtained using XFEM (3.5% difference). CorLAS method provided accurate results for crack-only defects with 7% difference. The extended finite element method (XFEM) was found to be very effective in predicting the failure pressure. In addition, compared to the traditional Finite Element Method (FEM) which requires extremely fine meshes and is impractical in modelling a moving crack, the XFEM is computationally efficient while providing accurate predictions.

Strain Analysis of Oil and Gas Pipeline with Dents Based on ILI Data

2016 ◽  
Vol 853 ◽  
pp. 372-376
Author(s):  
Zheng Qiang Lei ◽  
Jian Chen ◽  
Fu Xiang Wang ◽  
Ting Wang ◽  
Li Jian Zhou
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Oil And Gas ◽  
Strain Analysis ◽  
Gas Pipeline ◽  
Safe Operation ◽  
Buried Pipe ◽  
Strain Calculation ◽  
Acceptable Range ◽  
Integrity Analysis

Dents in an oil and gas pipeline can be detected by In-line-Inspection (ILI), and structure integrity analysis of the pipe with theses reported dents is important for the safe operation. Strain analysis of the dented pipe is a way of fine assessment and ASME B31.8 has established the strain assessment code and its acceptable range. However, the method of strain assessment is rarely used due to the difficulty of strain calculation for a buried pipe. In this study, features of ILI data are investigated to elaborate the necessary of filtering analysis for strain analysis of the dent with ILI data. Then typical filtering methods are used to smooth the ILI data, and strain analysis are carried out with the smoothed data to study the practicability of strain assessment. Profile and strain of a dent in D813 pipe were obtained by Finite Element Method (FEM). Then different filtering methods were used to smooth the simulated ILI data of the dent which were selected from FEM profile. Strain of the dent were also calculated by smoothed data with the latest ASME B31.8 code, and compared with it from FEM at last to prove the feasibility and validity of the filtering methods with ASME B31.8 code.

scholarly journals Monte Carlo-Based Finite Element Method for the Study of Randomly Distributed Vacancy Defects in Graphene Sheets

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Liu Chu ◽  
Jiajia Shi ◽  
Eduardo Souza de Cursi ◽  
Xunqian Xu ◽  
Yazhou Qin ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Monte Carlo ◽  
Natural Frequencies ◽  
Vacancy Defect ◽  
Honeycomb Lattice ◽  
Graphene Sheets ◽  
Pristine Graphene ◽  
Vacancy Defects ◽  
Element Method

This paper proposed an effective stochastic finite element method for the study of randomly distributed vacancy defects in graphene sheets. The honeycomb lattice of graphene is represented by beam finite elements. The simulation results of the pristine graphene are in accordance with literatures. The randomly dispersed vacancies are propagated and performed in graphene by integrating Monte Carlo simulation (MCS) with the beam finite element model (FEM). The results present that the natural frequencies of different vibration modes decrease with the augment of the vacancy defect amount. When the vacancy defect reaches 5%, the regularity and geometrical symmetry of displacement and rotation in vibration behavior are obviously damaged. In addition, with the raise of vacancy defects, the random dispersion position of vacancy defects increases the variance in natural frequencies. The probability density distributions of natural frequencies are close to the Gaussian and Weibull distributions.

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