Browsing by Author "Kessai, Idir"

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Contribution à l'analyse de la fiabilité et des défaillances des trépans de forage dans les systèmes de forage rotatifs
(Université M'Hamed Bougara Boumerdès : Faculté de Technologie, 2024) Kessai, Idir; Benammar, Samir(Directeur de thèse)
En forant un puits d'exploration ou bien d'exploitation, le système de forage pourrait être sujet à de nombreux problèmes et phénomènes qui le rendent inefficace pour achever les opérations de forage dans les délais qui leur avaient été accordés. Parmi ces problèmes, les défaillances des trépans de forage ont tendance à se manifester fréquemment sur pas mal de chantiers pétroliers. Dans ce contexte, la présente thèse vise à analyser et à évaluer la fiabilité et les défaillances de ces trépans en se servant de plusieurs approches telles que le modèle masse-ressort, la méthode des éléments finis et l'apprentissage profond.
Drill Bit Deformations in Rotary Drilling Systems under Large-Amplitude Stick-Slip Vibrations
(MDPI, 2020) Kessai, Idir; Benammar, Samir
In oil and gas industry, rotary drilling systems are used for energy exploration and productions. These types of systems are composed of two main parts: mechanical and electrical parts. The electrical part is represented by rotating motor called top drive; however, the mechanical part of the system is composed of tool string with many pipes, at the bottom end of these pipes the bit is attached to cut the rock during their contact. Since the bit is in a direct contact with rock characteristic variations, it can be under risk for heavy damage. The latter is principally caused by the fact that the rock–bit interaction term is highly nonlinear and unpredictable. In literature, many mathematical models have been proposed for rock–bit interaction, but they do not reflect the dynamic of the bit under vibrations since torsional and axial vibrations are strongly coupled and synchronized with it. In industrial development, the design of drill bit has faced many improvements in order to overcome these vibrations and mitigate unpredictable phenomena. Even though, the practical use of these drill bits confirmed that there are still many failures and damages for the new designs; moreover, bits’ virtual life become shorter than before. The objective of this study is to analyze the drill bit deformations caused by the stick-slip vibration phenomenon which is characterized by high-frequency high-amplitude in rotary drilling systems. The obtained results were validated through a case study of MWD (measurement while drilling) data of well located in a Southern Algerian oil field
Dynamic failure analysis and lifetime estimation of Tool-string in rotary drilling system under Torsional-Axial coupled vibrations
(Elsevier, 2022) Kessai, Idir; Benammar, Samir; Doghmane, M.Z.
Failure analysis and lifetime assessment of drilling systems are very important to reduce maintenance costs. Of all the failure modes, coupled vibration due to the stick–slip phenomenon is the most common problem that can affect rotary drilling systems. The main objective of this study is to estimate the number of cycles before failure (useful life) of the lower part of rotary drilling system toolstring under axial and torsional vibrations. To achieve this goal, a complete procedure based on different methods and approaches, such as: finite element method (FEM), rainflow counting method (RFM), Goodman approach (GA), S-N diagram and Miner’s rule, has been proposed. To this end, the FEM has been used to determine the loading cycles (equivalent stress); whereas, the number of stress cycles in the loading cycle diagram has been counted using RFM. The GA has been used to select the main cycles that can cause failure on the toolstring and to calculate their amplitudes. Then, S-N diagram has been used to determine the number of cycles to failure of the toolstring. Finally, Miner’s rule has been applied to find the approximate time to failure of the drilling system. Regarding the estimation of the toolstring lifetime, the results obtained have shown a good agreement with real data recorded in an oil field in Algeria
Preventive maintenance optimization of top drives in smart rotary drilling systems
(Springer, 2020) Kessai, Idir; Benammar, Samir; Doghmane, Mohamed Zinelabidine; Khelifa, Sadek
The increased competition in petroleum industry has pushed many companies to revise the preventive maintenance schedules in a way that allows them to use effectively the drilling equipments, and improve the availability of backup equipments while ensuring a continuous production for the hydrocarbons markets. This paper treated the optimization of equipments availability as an objective function, wherein, the manipulated parameters are failure rate, maintenance costs and production loss costs. The optimization algorithm has been transformed into Visual Basic Application (VBA), which provides optimum results in reasonable time. Moreover, the proposed approach has been applied to CANRIG 8050-AC 712 Top Drive used in smart rotary drilling systems; it is very expensive equipment and suffers a lot of failures due torsional vibrations. Furthermore, the effectiveness of the approach has been demonstrated through an application to field rotary drilling system belongs to the national drilling company ENAFOR
Weight-On-Bit variations analyses in the drillstring of rotary drilling systems under Stick-Slip vibrations
(Springer, 2022) Kessai, Idir; Doghmane, Mohamed Zinelabidine; Benammar, Samir
In this article, the main objective is to study the influences of weight-on-bit variation on the severity of stick-slip vibrations that appear in the toolstring of the rotary drilling systems. These types of vibrations can be very harmful to the equipment if not detected in real time and mitigated soon after. The only solution that is adopted in Algerian petroleum industry is the manipulation of drilling parameters, namely weight-on-bit and top drive torque. Where, the drillers as soon as they detect the appearance of such vibrations through abnormal decrease of rate of penetration (ROP) and the increase of the torque, they generally decrease the weight on bit and increase the torque of the top drive by increasing the angular velocity so that the vibrations will disappear and ROP will be maintained. However, the influences of the fast variation of these parameters (either increasing or decreasing) have not been previously studied. For that reason, the simulations conducted in this study are designed with different scenarios in order to analyze these effects for the severity of the stick-slip vibrations. Moreover, the importance of the analysis is that it allowed us to determine at what rate the Wob and Torque should be varied without creating sever vibrations that may damage the toolstring equipment. Therefore, it is highly recommended to consider the results of this study in suppressing the stick-slip vibrations