Reliability Methods Applied to Drilling Operations

Ligrone, A.; Botto, Giovanni; Calderoni, A.

doi:10.2118/29355-ms

Cited by 3 publications

(1 citation statement)

References 6 publications

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“…In order to describe the distribution law of fatigue life, the fatigue reliability theory was established by introducing reliability method. In recent years, some scholars have carried out fruitful research on reliability of fatigue crack detecting based on reliability theory [6,7]. However, the reliability of drill pipe's fatigue life prediction is rarely reported.…”

Section: Introductionmentioning

confidence: 99%

Research on Drill Pipe’s Fatigue Life Prediction Based on Reliability

2019

MSF

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Fatigue life of drill pipe is studied systematically based on reliability analysis. Calculation results show that bending and tensile stress in drill pipe body is significantly greater than that in the tool joint during drilling process. Drill pipe body’s fatigue strength is about 500MPa under the condition that the stress ratio is -1. The fatigue strength of tool joint is about 360MPa under the condition that the average tensile stress is 496MPa. The fatigue fracture position of drill pipe is concentrated on pipe body, and most fatigue cracks originate from pipe’s outer surface. Compared with material fatigue life, the fatigue life of whole drill pipe is significantly lower. Under the condition that the confidence level is 95% and deviation is 5%, drill pipe’s fatigue life distribution is normal distribution while the stress amplitude is 660MPa, 620MPa, 580MPa and 540MPa respectively. With the decreasing of stress amplitude, the peak of logarithmic fatigue life’ probability density distribution curve decreases gradually, and its dispersion increases gradually. Drill pipe’s fatigue life prediction equations whose reliability are 50%, 90%, 99% and 99.9% are calculated separately.

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Section: Introductionmentioning

confidence: 99%

Research on Drill Pipe’s Fatigue Life Prediction Based on Reliability

2019

MSF

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A New Approach to the Analysis of Drillstring Fatigue Behavior

Барышников¹,

Calderoni²,

Ligrone³

et al. 1997

SPE Drilling &Amp; Completion

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Summary This paper presents a method for determining the fatigue behaviour of Drill String (DS) components under given environmental conditions. Over the past few years. field data for DS failures have been gathered from certain wells drilled in Italy. West and North Africa. Clearly, fatigue phenomena were identified as the main cause of most of such failures. Among the several factors that can affect DS element fatigue resistance are tensile load. makeup torque. material properties. corrosive environment. abrasive wear and so on. However, simply on the basis of the existing guidelines it is difficult to define the real cause of a failure under given operating conditions. Based on a comparative study of full-scale fatigue test results and field data. a new approach is suggested for the analysis of some of the drilling technology factors that can affect the DS fatigue behaviour. IntroductIon DS is subject to great stress variations during service such as different kinds of dynamic and static loading. mud corrosion. temperature and so on. This, in combination with high stress concentrations. makes DS susceptible to fatigue damage which is still a major concern for Oil Companies and Drilling Contractors. On the other hand. in the available literature it is possible to find recommendations on how to take fatigue into account. As a matter of fact. according to, DS fatigue resistance analysis, for drilling directional wells. is carried out by means of drill pipe (DP) combined loading curves or given equations. Published curves display stress as a function of combined tension and dogleg, and show regions of "no fatigue damage" and "fatigue damage". However. this approach is based on the knowledge of the cyclic load history which is usually very difficult to quantify. Current methods for evaluating the drilling equipment fatigue failure risk as well as analysing failures are usually based on full-scale fatigue test results. The results of such investigations show that all factors affecting the DS element fatigue resistance can be divided into two main groups that can be defined as construction factors and drilling technology factors. Construction factors refer to fatigue characteristics of the tubular goods as they leave the manufacturer, such as the following:- type and size of DS components;- material characteristics;- design parameters;- strengthening methods (SRF, CW and so on). None of these factors can be changed at the rig site. On the other hand. drilling technology factors can be defined as those that can be "worked on" at the rig site such as:- tensile load;- makeup torque:- abrasive wear;- mud corrosion;- tripping technique, equipment and so on. In other words, drilling technology factors depend on the drilling technology itself. In this paper, the terms construction and drilling technology factors, as described above, will be used extensively. Full-scale fatigue tests on DS elements have been performed for years and represent the basis for evaluating the effect of these factors on DS fatigue resistance. However. the existing specifications limit the possibility of changing the DS element construction thus making any change of construction factors while operating "unpractical".

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Fatigue of Drillstring: State of the Art

Vaisberg

Vincké

Perrin

et al. 2002

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Fatigue des tiges de forage : état de l'art -La rupture des tiges de forage est un problème coûteux dans l'industrie de ce secteur. Bien que de nombreux spécialistes se soient penchés sur ce point, la fréquence des ruptures demeure toujours importante. Les ruptures par torsion ou par tension restent toutefois limitées, car les causes en sont connues et peuvent être aisément corrigées, en revanche, les ruptures par fatigue sont plus difficilement appréhendées. Le présent article se propose d'établir un état de l'art sur la fatigue des tiges de forage. La prédiction et les calculs d'un dommage de fatigue sont ici abordés selon la méthode simpliste du cumul de dommage (somme de Miner) mais aussi de façon plus complexe, par l'utilisation des éléments de la mécanique de la rupture. Les méthodes d'inspection et leurs limitations sont discutées, des recommandations sont également émises. Par ailleurs, des tests de fatigue sont mis en oeuvre face au risque humain ou environnemental. Cette étude précise les conditions de chargement, la fréquence des essais, le nombre et la taille des éprouvettes. Nous rappelons les effets d'un environnement corrosif ainsi que leur prévention, bien que ce sujet ne soit pas l'objet principal de cet article. Le dernier chapitre résume les différentes façons d'améliorer les tiges de forage. À ce titre, il aborde la géométrie, le design des connexions, les propriétés de l'acier telles que la résilience, le rechargement dur des tool-joints et l'inspection des garnitures de forage.

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Reliability Methods Applied to Drilling Operations

Cited by 3 publications

References 6 publications

Research on Drill Pipe’s Fatigue Life Prediction Based on Reliability

Research on Drill Pipe’s Fatigue Life Prediction Based on Reliability

A New Approach to the Analysis of Drillstring Fatigue Behavior

Fatigue of Drillstring: State of the Art

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