Reliability of Electric Submersible Pumps ESP & Determination of Weibull Parameters for Failure Characterization, Ecuador Case Study

2021 ◽  
Author(s):  
Diego Ayala ◽  
Wilson Padilla ◽  
Luis Carrera
Keyword(s):  
Failure Rate ◽  
Life Time ◽  
Production Costs ◽  
Failure Behavior ◽  
Operating Life ◽  
Weibull Parameters ◽  
Warranty Period ◽  
Asymmetric Data ◽  
Maintenance Program ◽  
Initial Stage

Abstract The current research focuses on data modeling of ESP (Electric Submersible Pumps) reliability by obtaining, through mathematical calculations, the parameters that define the Weibull shape (β), scale (ɳ) and location (ϒ) parameters. The scale parameter ɳ is the characteristic life at which 63.2% of the population has failed. These parameters can be helpful in characterizing failure behavior and the ESP system run life. This research stemed from the need to better understand failure behavior to improve maintenance program design and enhance equipment reliability.160 wells from four fields (7-21, 56, 57) of the Ecuadorian Oriente basin were analyzed. Well selection considered only the mechanic failures and excluded other type of failures leaving aside the ESP failures caused by operative issues (reservoir, completions, workover, redesign, zone change). Three mathematical tools were applied to determine the Weibull parameters more accurately. Another type of analysis could have limited this research since the normal distribution shows limitations with asymmetric data, and the exponential distribution assumes a fixed failure rate, but the ESP failure behavior is asymmetric and the failure rate is variable through time due to factors such as wear and also infant failures (e.g. installation errors). For these reasons, Weibull distribution is the best option because it fits asymmetric data better and it has a variable failure rate. Determining the value of the Weibull parameters can assist in answering questions such as: what percentage of failures is expected to occur in time? How many failures can be expected before the warranty period? When should regular maintenance be scheduled? Ultimately, Weibull parameters are the basis of any future reliability analysis. The Weibull parameters obtained in this study can be applied for future ESP reliability analyzes that are being operated in any field in the Oriente Basin of Ecuador. From the research, two relevant findings were foundThere are a significant number of failures in the initial stage of operation of the pumps,, which could be associated with the installation of the equipment, and the failure risk is drastically reduced in the equipment that reaches life time similar to the characteristic life (ɳ)and pumps that operate without failure to a time similar to characteristic life (ɳ) continue to follow this trend throughout their operating life. Initial stage failures are presumed to be associated with unanticipated conditions: solid binding, design errors, defective equipment, or assembly of equipment with reused and new parts. The performance of the ESP affects the productivity of the wells and therefore will influence decision-making to develop a field. The reliability of the ESP systems can favor the productivity of a field when the equipment works within its efficiency range without showing recurrent failures. This significantly improves field production costs and profitability.

IR Thermography for Temperature Measurements and Fault Location on AlGaN/GaN HEMTs and MMICs

2015 ◽  
Author(s):  
Lény Baczkowski ◽  
Franck Vouzelaud ◽  
Dominique Carisetti ◽  
Nicolas Sarazin ◽  
Jean-Claude Clément ◽  
...  
Keyword(s):  
Fault Location ◽  
Hot Spot ◽  
Life Time ◽  
High Electron Mobility Transistors ◽  
Junction Temperature ◽  
High Electron ◽  
Ir Thermography ◽  
Operating Life ◽  
Gan Hemt ◽  
Electron Mobility Transistors

Abstract This paper shows a specific approach based on infrared (IR) thermography to face the challenging aspects of thermal measurement, mapping, and failure analysis on AlGaN/GaN high electron-mobility transistors (HEMTs) and MMICs. In the first part of this paper, IR thermography is used for the temperature measurement. Results are compared with 3D thermal simulations (ANSYS) to validate the thermal model of an 8x125pm AIGaN/GaN HEMT on SiC substrate. Measurements at different baseplate temperature are also performed to highlight the non-linearity of the thermal properties of materials. Then, correlations between the junction temperature and the life time are also discussed. In the second part, IR thermography is used for hot spot detection. The interest of the system for defect localization on AIGaN/GaN HEMT technology is presented through two case studies: a high temperature operating life test and a temperature humidity bias test.

Automatic Condition Monitoring and Early Fault Detection of Gearbox

2009 ◽  
Author(s):  
Dong Wang ◽  
Qiang Miao ◽  
Chengdong Wang ◽  
Jingqi Xiong
Keyword(s):  
Condition Monitoring ◽  
Wavelet Packet ◽  
Life Time ◽  
Health Condition ◽  
Evaluation Index ◽  
Dynamic Threshold ◽  
Time Data ◽  
Machinery Condition Monitoring ◽  
Maintenance Program ◽  
Gear Fault

Condition based maintenance (CBM) improves decision-making performances for a maintenance program through machinery condition monitoring. Therefore, it is a key step to trace machinery health condition for CBM. In this paper, a novel method is proposed to establish a health evaluation index named automatic evaluation index (AEI) and its corresponding dynamic threshold using Wavelet Packet Transform (WPT) and Hidden Markolv Model (HMM). In this process, WPT is used to decompose signal into detail signals and exhibits prominent gear fault features. In addition, HMM employed here is to recognize two concerned states of gear in the whole life validation, including normal gear state and early gear fault state. It is also important to build a dynamic threshold to differentiate the two states automatically. The proposed dynamic threshold not only renews by itself according to the history values of AEI but also easily and automatically detects occurrence of gear early fault. Finally, a set of whole life time data ending in gear failure is used to verify the proposed method effectively. Further, some related parameters included in this method are discussed and the obtained results show that condition monitoring performance of the proposed method is excellent in detection of gear failure.

Important Mechanical and Chemical Factors in the Failure Behavior of Polybutadiene Rubber Undergoing Oxidative Aging at Ambient Temperature

1969 ◽  
Vol 42 (4) ◽  
pp. 1095-1121 ◽  
Author(s):  
C. S. Kim
Keyword(s):  
Oxidative Degradation ◽  
Life Time ◽  
Failure Behavior ◽  
Oxidative Aging ◽  
Mechanical Effects ◽  
Chemical Effects ◽  
Polybutadiene Rubber ◽  
Atmospheric Exposure ◽  
Chemical Factors

Abstract Zhurkov's molecular kinetic concept of failure for hard solid materials was extended for application to rubber systems which undergo oxidative degradation during long-term atmospheric exposure. In an effort to analyze the chemical and mechanical effects separately, the dependency of the life-time of the uniaxially stressed rubber was expressed in terms of (1) chemical effects involving the primary chemical bonds in the effective chains, and (2) mechanical effects involving the network structure of the rubber.

Investigation of fatigue performance of low temperature alloys for liquefied natural gas storage tanks

2015 ◽  
Vol 229 (7) ◽  
pp. 1300-1314 ◽  
Author(s):  
Dong-Jin Oh ◽  
Jae-Myung Lee ◽  
Byeong-Jae Noh ◽  
Wha-Soo Kim ◽  
Ryuichi-Ando ◽  
...  
Keyword(s):  
Low Temperature ◽  
Natural Gas ◽  
Structural Integrity ◽  
Liquefied Natural Gas ◽  
Operating Conditions ◽  
Production Costs ◽  
Fatigue Performance ◽  
Nickel Steel ◽  
Storage Tanks ◽  
Operating Life

One of the most important issues associated with liquefied natural gas (LNG) storage tanks, such as LNG carrier cargo tanks and land LNG tanks, is their structural integrity. In order to ensure the operating life and safety of LNG storage tanks used under operating conditions such as thermal and cyclic loadings, the securing of safety evaluations for fatigue performance is considered to be of particular importance. There have been various efforts to reduce the production costs of LNG storage tanks, such as the optimum selection of materials and the development of new low temperature materials. This, the motivation of this study is to evaluate new material candidates for LNG storage tanks. This study begins with a comprehensive review of the characteristics of low temperature alloys such as SUS 304L, Invar, A5083 and 9% Ni steel that are widely used for LNG storage tanks. Then, the fatigue characteristics of a newly developed low temperature material, 7% nickel steel are investigated. Finally, the fatigue performance of 7% nickel steel is compared with that of 9% nickel steel.

scholarly journals In silico analysis of resveratrol induced PD-L1 dimerisation

2021 ◽  
pp. 39-47
Author(s):  
Viktor A. Urban ◽  
Alexander I. Davidovskii ◽  
Valery G. Veresov
Keyword(s):  
T Cell Activation ◽  
Cell Activation ◽  
Checkpoint Inhibitors ◽  
In Silico Analysis ◽  
Life Time ◽  
Production Costs ◽  
Ligand Docking ◽  
Checkpoint Pathway ◽  
Dynamics Simulations ◽  
Small Molecular Inhibitors

T-cell activation through the blockade of PD-1 – PD-L1 interactions is recognised at present as one of the most promising strategies in the cancer treatment and a number of antibodies targeting the PD-1 – PD-L1 immune checkpoint pathway have been approved after successful clinical trials. However, the use of antibodies suffers from a number of shortcomings including poor tissue and tumor penetration, long half-life time, poor oral bioavailability, and expensive production costs. Small molecule based therapeutic approaches offer the potential to address the shortcomings of the antibody-based checkpoint inhibitors. At present, more than twenty small molecular inhibitors of the PD-1 – PD-L1 interactions whose scaffold is based on substituted biphenyl group connected to a further aromatic ring through a benzyl ether bond have been identified and patented by Bristol – Mayers – Squibb (USA). Structural studies have shown that all these compounds act by inducing the dimerisation of PD-L1 that makes PD-L1 non-competent for forming complex with PD-1. Very recently, the dietary polyphenol resveratrol (RSV) has been reported to inhibit the PD-1 – PD-L1 interactions through the induction of the PD-L1 dimerisation but the mechanisms remain unclear. Here, computational structural biology tools combining protein – protein and protein – ligand docking with molecular dynamics simulations were used to gain structural insights into the mechanisms of the RSV-induced dimerisation of PD-L1.

Production and maintenance strategies for parallel machines with load transfer in case of failure

2019 ◽  
Vol 25 (4) ◽  
pp. 525-544
Author(s):  
Jérémie Schutz ◽  
Anis Chelbi ◽  
Nidhal Rezg ◽  
Safa Ben Salem
Keyword(s):  
Production Rate ◽  
Failure Rate ◽  
Parallel Machines ◽  
Load Transfer ◽  
Production Costs ◽  
The Other ◽  
Random Time ◽  
Production Plan ◽  
Optimal Production ◽  
Content Type

PurposeThe purpose of this paper is to deal with the problem of integration of production and maintenance policies. In this context, the authors consider production systems made of parallel machines producing a single product over a finite horizon made of equal periods for which a forecasted demand is known. The authors investigate the impact of switching production in case of failure of any given machine.Design/methodology/approachA mathematical model is first developed to find an optimal production plan which minimizes the average total storage, shortage and production costs. Then, using this optimal production plan and taking into account the influence of the production rate on the degradation of each machine, optimal preventive maintenance (PM) policies are proposed for the situations with and without switching.FindingsOptimal production rates are determined for each production period and for each machine. Optimal PM periods are also computed for each machine.Practical implicationsUsually, in manufacturing systems, the production rate of a machine influences its failure rate. In case a machine fails, it takes a random time to repair it during which production is lost. The paper attempts to propose a switching policy (SP) according to which the lost production is compensated by all the other machines. The effects of the SP coupled with the PM strategy are shown through a numerical example.Originality/valueContrarily to previous works, the authors consider more realistic settings with a non-negligible random time for repairing failed machines. In order to compensate the lost production during the repair of a failed machine, a SP is proposed to transfer the load uniformly to all the other machines. As a result, those machines will produce at a higher production rate and will consequently have their failure rate increased. It will therefore be essential to determine an optimal PM schedule knowing that durations of these activities are not negligible. It is shown that the simultaneous implementation of periodic PM and load transfer in case of failure is the most economical integrated strategy.

Non-parametric statistical test for testing exponentiality with applications in medical research

2019 ◽  
Vol 29 (2) ◽  
pp. 413-420
Author(s):  
MMM Mansour
Keyword(s):  
Failure Rate ◽  
Survival Data ◽  
Treatment Method ◽  
Negative Influence ◽  
Statistical Test ◽  
Failure Behavior ◽  
Survival Times ◽  
Increasing Failure Rate ◽  
Parametric Statistical Test ◽  
Non Parametric

The aim of designing the non-parametric statistical test in this paper is to assess some treatment methods by studying the failure behavior of the observed survival data. A treatment method represents the application of different healthcare interventions for the cure or reduction of disease-related symptoms. The survival times of patients are registered after applying the proposed treatment method. The behavior of the observed data in this paper is assumed to enjoy an increasing failure rate or constant failure rate (exponential case) property. If the survival data have increasing failure rate property, then the proposed treatment method is useless (has negative influence on patients) and another method should be recommended, while if the collected data have exponential property, then the proposed treatment method has no positive or negative influence on patients. To guarantee a right assessment using the proposed statistical test, its efficiency and power are calculated and compared with other tests. The proposed statistical test is applied in case of some cancer treatments.

Dressing of Vitreous Bonded Wheels for Continuous Generating Grinding of Gears

2005 ◽  
Vol 291-292 ◽  
pp. 201-206 ◽  
Author(s):  
Berend Denkena ◽  
M. Reichstein ◽  
F. Catoni
Keyword(s):  
Heat Treatment ◽  
Load Capacity ◽  
Life Time ◽  
Production Costs ◽  
Speed Ratio ◽  
Present Contribution ◽  
Production Chain ◽  
Quality Requirements ◽  
Gear Grinding ◽  
Generating Grinding

Grinding is a final step in the production chain of gears and therefore determines the quality of the product. In the industrial practice gears are cut - generally by means of a hobbing process - and their surface is hardened through a heat treatment, which has the target of increasing the wear resistance of the tooth flanks. Grinding is therefore necessary to remove the material distortions originating during the heat treatment and to fulfill dimensional and quality requirements. Usually only gears with high quality requirements are ground. Otherwise grinding is not carried out to reduce the production costs. In the recent years however the percentage of ground gears has been growing continuously due to the rising demands on load capacity, quiet running and life time as well as the increasing performance offered by the grinding processes. Generating grinding by means of cylindrical grinding worms shows the highest potential among the existing processes for gear grinding due to the high material removal performance that can be achieved. In order to use dressable worms efficiently the dressing technology has to be optimized. The present contribution describes the technology for dressing vitreous bonded grinding worms. This process is based on the use of form dressing rollers by means of which the grinding worm geometry and topography are generated. The investigations are aimed at analyzing the influence of the dressing parameters, in particular the speed ratio between dressing and grinding tool, and the attainable gear quality and surface properties. The results show significant dependencies between the dressing strategy and the grinding results.

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