Publications Internationales

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Author: search.filters.author.Abdelbaki, Noureddine

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    Effect of shape factor on structural reliability analysis of a surface cracked pipeline-parametric study
    (2019) Guillal, Abdelkader; Abdelbaki, Noureddine; Bensghier, Mohamed El Amine; Betayeb, Mourad; Kopei, Bogdan
    The variation of crack shape factor (a/c) during propagation has an important role on calculation of the stress intensity factor (SIF), where imprecise estimation of this latter can lead us to an inaccurate prediction of failure probabilities. For the case of external cracked surface pipeline carried oil and gas products, such estimation can results undesired fault decisions like excessive repairs action or inspection planning. In this paper, the structural integrity analysis of pipeline with semi elliptical crack on the external surface is evaluated. Reliability calculations expressed in term of reliability index β are carried out based on Monte Carlo simulation and First Order reliability Method (FORM). The crack shape factors are varied to cover a variety of geometries from shallow to deep cracks while fatigue crack growth is assumed in depth direction. For SIF estimation, surface and deep point are considered. Results of the analysis indicate that for a constant crack depth a/t, the reliability index is strongly affected by a/c ratio and the trend is not similar in deep and surface point for different crack shapes.
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    Using a supperficially treated 2024 aluminum alloy drill pipe to delay failure during dynamic loading
    (Elsevier, 2019) Belkacem, Lallia; Abdelbaki, Noureddine; Otegui, Jose Luis; Gaceb, Mohamed; Bettayeb, Mourad
    For many years, a critical factor while drilling deep wells in Algeria oil fields has been the fatigue loads in drill strings used in high tortuosity sections. One solution is the use of drill pipes made of alternative lighter materials instead of conventional steel. A thorough study of superficially (ST) treated 2024 aluminum alloy joined to steel drill pipes in crooked well trajectories is presented in this article. This work discusses several limiting loads exerted on the drill pipes that affect the drilling operation such as axial, twisting and bending forces, which lead to combined cyclic loads. This study is aimed to determine whether it is possible to extend the drilling operation by joining ST 2024 aluminum alloy drill pipes into the drilling string, without losing drilling stability or reliability. It is established that the ST 2024 aluminum alloy drill pipe exerts significant influence on the allowable combined load, but affects to a larger extent the critical load at which loss of drilling string stability occurs, along with improved resistance to wear and corrosion, even at high temperature
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    Probabilistic investigation on the reliability assessment of mid- and high-strength pipelines under corrosion and fracture conditions
    (Elsevier, 2020) Guillal, Abdelkader; Ben Seghier, Mohamed El Amine; Abdelbaki, Noureddine; Correia, José A.F.O.; Zahiraniza, Mustaffa; Nguyen-Thoi, Trung
    In order to reduce the economic costs of pipeline construction projects and for offering a good combination of strength and toughness for efficient transportation of large quantities of hydrocarbon products under high pressure, High Strength Steels (HSS) such as API 5L X70 to X120 are used recently in the construction of pipeline systems for the large oil and gas projects. The commonly utilized models for the reliability evaluation of the HSS pipelines may lead to some conservatism regarding the used data. This paper aims to evaluate the system reliability of HSS pipelines with combined corrosion and cracks defects. Therefore, two failure modes as the plastic collapse and fracture are considered. The effect of different correlations under the term of the strain-hardening exponent that depends on the yield to ultimate tensile strength (Y/T) ratio is investigated. The reliability index of HSS pipelines is evaluated separately for each failure mode using the subset simulation technique. Herein, the tensile strength proprieties of the HSS pipelines are taken into consideration, while the applied methodology utilizes novel probabilistic models to predict the burst pressure for the plastic collapse failure mode. The steels toughness is taken as equal to the minimum requirement for both the ductile and the brittle fracture arrest applied in the HSS pipelines. Moreover, the reliability of the system with multiple failure modes is evaluated to show the mutual existence effect of crack and corrosion defects on pipeline safety
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    Drill string fatigue failure and lockup risks assessment in tortuous trajectory well in Algeria
    (2017) Belkacem, Lallia; Abdelbaki, Noureddine; Gaceb, Mohamed; Bouali, Elahmoun; Bettayeb, Mourad
    Failure due to fatigue and lock up risks for drilling pipes in tortuous trajectory is a very costly problem in oil and gas industry, since the cyclic loading which occurs while rotating bent drill pipes in a dog leg are more dangerous than rotating buckled drill pipes. This study is aimed to assess these risks and determine whether by integrating 2024 aluminium alloy drill pipes in drilling string, it is possible to extend the drilling operation without having detrimental impact on the drilling string integrity. Accordingly, the obtained results showed that, even though steel drill pipes have better mechanical properties, compared to 2024 aluminium alloy drill pipes, the latter have a better fatigue resistance even in the simultaneous presence of high applied torque and axial load, and severe dog-legs, beside good resistance to wear and corrosion even at high temperature, thereby reducing environmental trash and full consumption in order to minimise pollution
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    Establishment of data base and a classification of defects in the metal of pipes according to their severity
    (Elsevier, 2012) Bettayeb, M.; Bouali, E.; Abdelbaki, Noureddine; Gaceb, M.
    Given the distances between areas of production and consumption of hydrocarbons, transport by pipeline is the most competitive means. These pipelines made of metal pipes can contain several types of defects of different origins. These defects can lead to pipeline failures that may have serious consequences resulting in ecological or financial disasters. The causes of these failures can be of various kinds. To assess the integrity and study the ageing of hydrocarbons transport pipelines is a current problem in the world which must be solved. The degraded state of thousands of kilometers of pipeline in the world requires the elaboration of rehabilitation by repair or replacement programs of sections in poor condition. If on one hand rehabilitation operations do improve the safety of hydrocarbons transport pipelines and prolong their remaining life, they are very expensive on the other. Therefore they must be carried out according to a previously well established plan, which determines the priority given. This priority must be defined by a multi-criteria evaluation, which also includes the criterion of severity of the defects located in the pipes metal according to the result of previous inspections of the pipelines towards the importance and the integrity of each section of the pipe.In this context the elaboration of a database and a classification of the defects in the metal of the hydrocarbons transportation pipes according to their severity are essential in this study
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    Analysis of predictive models of oil transportation ducts rehabilitation
    (2012) Abdelbaki, Noureddine; Bouali, Elahmoun; Gaceb, Mohamed; Bettayeb, Mourad
    The actions of the various phenomena of corrosion, mechanical constraints and others, contribute to the degradation of hydrocarbons transportation ducts. The combinations of th ese phenomena accelerate pipe ageing, and this results in the increase of the frequency of leaks interventions and pipe ruptures. The only way to struggle against the ageing of oil transportation pipelines is the rehabilitation. This will allow the re - serv icing of pipes whose resistance characteristics are degraded. One of the major difficulties, during the conception of a pipeline rehabilitation program, is the determination of the specific sections to rehabilitate. Indeed if there is any real risk not to do enough rehabilitation in the one hand, there is a risk to bad rehabilitation on the other. The decision to continue to maintain, renovate or replace some degraded sections of a pipeline is not an easy task, and requires development of forecasting models that will enable decision - makers to take the right decisions on the middle and long term. In this context, this study is devoted to analysis of problems associated with statistical exploitation of controls and repair files of aged pipes, establishing acti on plans and controlling the ageing of hydrocarbons transportation pipelines
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    Fiabilist and economic approaches to optimisation of the renewal of hydrocarbons transporting pipelines
    (2013) Abdelbaki, Noureddine; Gaceb, Mohamed; Bouali, Elahhmoune; Bettayeb, Mourad; Bouzid, Rachid
    Problems of hydrocarbons transporting pipelines agi ng and rehabilitation are currently a major concern for operators of such installations. Rehabilitating and insuring hydrocarbons transporting pipelines, require interventions, such as the renovation of existing lines, the replacement of some pipelines with new ones, in order to meet the growing demand of consumers and improve the supply reliability. In this context, a decision to repair or replace a section of pipe must co mbine both a technical analysis of failures and sound economic analysis of the choice of possible interventions , which is the purpose of this study, dedicated to research and policy determination of repair and replac ement of aged pipe sections, taking into account the factors mentioned above, and based on significant feedback
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    Tensile and torsional loads stress distribution along the drill string for deep wells
    (Springer, 2015) Belkacem, Lallia; Abdelbaki, Noureddine; Gaceb, Mohamed; Bouali, Elahmoun; Hedjaj, Ahmed; Bettayeb, Mourad
    Common knowledge and rule of thumb tell us that tensile failures will mostly occur in the pipe body, while torsion failures will occur in the tool joints. The total stresses on the drill string should be considered which are induced by combined bending, torsion and tensile stresses. The latter can usually be operating up until 80 % of the pipe body yield stress, a level which is considered as a safe working limit. Moreover, torque and drag are caused by the lateral forces and the friction between the borehole wall and the drill pipe. The lateral forces depend on the weight of the drill string. Torque and drag are sometimes overlooked when drilling simple wells. In deep well this is not acceptable. Proper decision made using correct torque and drag can make all the difference between TD drilling and suspended drilling. Therefore the over pull load plus the torque are the most important points to be considered in deep well drilling, since the resistance of the drill string body to the combined efforts will probably limit its tensional limit. By this I mean, exerting both a tension and torsion load on the drill string of this later will weaken its yield stress consequently applying a high tension effort combined with a significant torque lead to plastifying of the drill pipe body thus reducing its fatigue life. This problem is well observed in back-reaming operation. The results show that fatigue damage from rotation in dogleg during backreaming operation is a significant problem if the severity is greater than the critical value. So the position of drill pipe in the string will influence the amount of fatigue damage it sustains. Furthermore, back reaming can reduce the fatigue life of the drill pipe significantly because of the stress reversal of the drill string under tension in a dogleg
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    Pipeline test finds Monte Carlo superior to FORM
    (2015) Bettayeb, Mourad; Abdelbaki, Noureddine; Gaceb, Mohamed; Bouali, Elahmoune
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    Methods of the rational choice of a labyrinth seal design for gas pumping units
    (2013) Bellaouar, A.; Kopey, B. V.; Abdelbaki, Noureddine
    This present paper describes a method of improving the labyrinth seal design by the development of three-dimensional parametric computer of its model and an anal-ysis of its work for gas pumping units (GPU) using the finite-element method. The authors have improved design labyrinth seal of the GPU according to the criterion of minimum pressure in the last gap by Gauss-Seidel method of optimization, which will increase GPU operational efficiency by reducing flowing medium at various operating modes of GPU. It is shown that change of geometrical sizes and form of creating more compact part of labyrinth seal with inclination them toward greater pressure for an angle of 80° decrease leakages of gas, that in same time considerably influences on the expense of working environment on the output of labyrinth seal