Helical Buckling of Pipes in Extended Reach and Horizontal Wells—Part 1: Preventing Helical Buckling

1993 ◽  
Vol 115 (3) ◽  
pp. 190-195 ◽  
Author(s):  
J. Wu ◽  
H. C. Juvkam-Wold ◽  
R. Lu
Keyword(s):  
Theoretical Analysis ◽  
Current Literature ◽  
Laboratory Experiments ◽  
Development Process ◽  
Theoretical Study ◽  
Horizontal Wells ◽  
Buckling Load ◽  
New Equation ◽  
Sinusoidal Buckling ◽  
Helical Buckling

This paper studies the helical buckling of pipes (drillstring and tubing) in extended reach and horizontal wells, theoretically and experimentally, resulting in new equations to correctly predict and effectively prevent the helical buckling of pipes in such wells. The theoretical study shows that the so-called helical buckling load that appears in the current literature is only the average axial load in the helical buckling development process. The laboratory experiments confirm the theoretical analysis. The new helical buckling load equations are formulated by combining the theoretical analysis and the experimental results, thereby resolving the existing assumption-and result inconsistency in the current literature. The new equation predicts the true helical buckling load to be about 1.3 times the so-called helical buckling load in the current literature, and about 1.8 times the critical buckling load that predicts the onset of sinusoidal buckling. Consequently, larger bit weights or packer setting loads can be applied to increase the drilling rate or to ensure a proper seal, before the helical buckling of the pipes can occur.

The Effect of Wellbore Curvature on Tubular Buckling and Lockup

1995 ◽  
Vol 117 (3) ◽  
pp. 214-218 ◽  
Author(s):  
J. Wu ◽  
H. C. Juvkam-Wold
Keyword(s):  
Laboratory Experiments ◽  
Horizontal Wells ◽  
Buckling Load ◽  
Small Scale ◽  
Buckling Loads ◽  
Compressive Loads ◽  
Helical Buckling ◽  
Outer Curve

This paper studies tubular buckling in curved wellbores (such as the build section of horizontal wells) and its effect on tubular “lockup” in horizontal or extended-reach wells. New buckling load equations are derived to properly predict tubular sinusoidal and helical buckling in such wellbores. The results show that the buckling loads to initiate sinusoidal and helical buckling of tubulars in curved wellbores are usually much larger than those in straight wellbores. This is because the curved wellbore tends to hold the axially compressed tubular against the outer-curve side of the wellbore. The tubular becomes less easy to buckle until higher axial compressive loads are applied. Less tubular lockup risk is then predicted for tubulars in horizontal or extended-reach wells by using the new buckling load equations. The new buckling loads in curved wellbores agree with those in straight wellbores when wellbore curvature approaches zero. Small-scale laboratory experiments also confirmed these theoretically derived buckling loads.

Helical Buckling of Pipes in Extended Reach and Horizontal Wells—Part 2: Frictional Drag Analysis

1993 ◽  
Vol 115 (3) ◽  
pp. 196-201 ◽  
Author(s):  
J. Wu ◽  
H. C. Juvkam-Wold
Keyword(s):  
Differential Equation ◽  
Analytical Solution ◽  
Laboratory Experiments ◽  
Horizontal Wells ◽  
Force Balance ◽  
Axial Loads ◽  
Frictional Drag ◽  
Well Completion ◽  
Helical Buckling ◽  
Drag Analysis

This paper studies the frictional drag of helically buckled pipes (drillstring and tubing) in extended reach and horizontal wells to correctly predict the actual bit weight or packer load, in cases where helical buckling of pipes may have occurred. Helical buckling of pipes in such wells may occur, since large axial loads are often required. The differential equation of axial force balance with consideration of the axial friction for helically buckled pipes is resolved, and the solution shows that when the pipes are helically buckled, the frictional drag will become very large. The actual bit weight for drilling or packer load for well completion may therefore become much smaller than estimated under the unbuckled pipe conditions. The analytical solution is also shown to agree with the results from laboratory experiments, which simulate the real wellbore-pipe conditions. An example is provided to show the calculation procedure and the importance of the results.

scholarly journals Notched Hollow Square Section Steel Column Buckling

2019 ◽  
Vol 4 (1) ◽  
pp. 81-84
Author(s):  
Zia Razzaq ◽  
Solomon Tecleab
Keyword(s):  
Carrying Capacity ◽  
Laboratory Experiments ◽  
Theoretical Study ◽  
Buckling Load ◽  
Load Carrying Capacity ◽  
Column Buckling ◽  
Buckling Loads ◽  
Steel Columns ◽  
Load Carrying ◽  
Steel Column

Presented in this paper is an outcome of a study to assess the effect of section loss in the form of longitudinal notches on the buckling load of hollow square section steel columns. The theoretical study includes buckling load estimates based on both an iterative equilibrium as well as a non-iterative energy approach. Buckling loads based on sample laboratory experiments are also presented. The study shows that the presence of a notch can significantly reduce the axial load-carrying capacity of a steel column.   

Development of Low Carbon High Strength H-Beam Steel

2010 ◽  
Vol 168-170 ◽  
pp. 969-972
Author(s):  
Jian Qing Qian ◽  
Ji Ping Chen ◽  
Bao Qiao Wu ◽  
Jie Ca Wu
Keyword(s):  
Mechanical Properties ◽  
Laboratory Experiments ◽  
Theoretical Study ◽  
High Strength ◽  
Rolling Process ◽  
Low Carbon ◽  
Study Product ◽  
H Beam ◽  
Nitrogen Alloy

The application of vanadium-nitrogen alloy to develop a certain low carbon high strength H-beam steel was determined through the combination of theoretical study, product requirements and existing practical conditions. The specific rolling process was further defined through laboratory experiments. The developed low carbon high strength H-beam steel was trial produced and its properties were also analyzed. The results showed that the newly developed low carbon high strength H-beam steel had excellent mechanical properties and good weldability.

scholarly journals Self-realisation, self-actualisation and self-efficacy concepts theoretical analysis

2021 ◽  
Vol 27 (2) ◽  
pp. 7-15
Author(s):  
Tatyana Petrovna Opekina ◽  
Natalya Sergeevna Shipova
Keyword(s):  
Comparative Analysis ◽  
Theoretical Analysis ◽  
Goal Setting ◽  
Self Efficacy ◽  
Theoretical Study ◽  
The Self ◽  
Social Orientation ◽  
Similarities And Differences ◽  
The Individual ◽  
External Forces

This article presents the results of a theoretical study of self-realisation, self-actualisation and self-efficacy phenomena. The main aspects of understanding and correlating these phenomena in classical and modern Russian and foreign psychology are described. The highlighted concepts related to the phenomenon of self-realisation, both in the field of psychology and pedagogy. The similarities and differences of the self-realisation, self-actualisation, self-efficacy phenomena, as well as their correlation and comparison are presented. A comparative analysis of the studied concepts is given. According to the results of the theoretical analysis, the processes of self-realisation and self-actualisation are based on the inner motivation of a person to grow, develop personality, realise its potential. Both of these processes, due to their subjectivity, are difficult to observe and measure from the outside. We have highlighted the main differences, consisting in a greater awareness and orderliness of the process of self-realisation, as well as its predominantly "social" orientation, while self-actualisation is often associated with the struggle with external forces, the desire for self-realisation is rather approved and supported by the society. The concepts of self-realisation and self-efficacy are united by their inherent representation in the external plane of the life of the individual, as well as awareness, activity, goal-setting, and an orientation towards achieving success. In contrast to self-efficacy, self-release is a process rather than a sustainable phenomenon, and can be expressed both externally and internally through a connection with the value-semantic, motivational spheres of the individual.

Incorporating Maintenance Infeasibilities in an Aircraft Rotation Planning Model

2021 ◽  
pp. 2050025
Author(s):  
Ram Gopalan
Keyword(s):  
Computational Complexity ◽  
Theoretical Analysis ◽  
Development Process ◽  
Planning Model ◽  
Sufficient Time ◽  
Fleet Assignment ◽  
Routing Problem ◽  
Eulerian Graph ◽  
Maintenance Requirements ◽  
Periodic Routing

In any airline’s schedule development process, aircraft rotations must be planned for individual fleet types after fleet assignment. The aircraft rotation plans must conform to stringent maintenance requirements and this problem can be formulated as a periodic routing problem on an Eulerian graph. We analyze the computational complexity of developing maintenance rotations when some overnighting aircraft may not have sufficient time on the ground to complete extended maintenance (referred to as a maintenance infeasibility). The paper also provides a theoretical analysis of heuristics for the aircraft maintenance rotation problem with maintenance infeasibilities.

scholarly journals Mechanical Respond and Failure Mode of Large Size Honeycomb Sandwiched Composites under In-Plane Shear Load

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4248 ◽  
Author(s):  
Wang ◽  
Wang ◽  
Liu ◽  
Zhang ◽  
Wan ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Shear Strain ◽  
Failure Mode ◽  
Field Distribution ◽  
Shear Failure ◽  
Buckling Load ◽  
Analysis Method ◽  
Plane Shear ◽  
Large Size ◽  
Honeycomb Sandwich

The present work focuses on the in-plane shear respond and failure mode of large size honeycomb sandwich composites which consist of plain weave carbon fabric laminate skins and aramid paper core. A special size specimen based on a typical element of aircraft fuselage was designed and manufactured. A modified in-plane shear test method and the corresponding fixture was developed. Three large size specimens were tested. The distributed strain gauges were used to monitor the mechanical response and ultimate bearing capacity. The results show that a linear respond of displacement and strain appears with the increase of the load. The average shear failure load reaches 205.68 kN with the shear failure occurring on the face sheet, and the maximum shear strain monitored on the composite plate is up to 16,115 με. A combination of theoretical analysis and finite element method (FEM) was conducted to predict the shear field distribution and the overall buckling load. The out-of-plane displacement field distribution and in-plane shear strain field distribution under the pure shear loading were revealed. The theoretical analysis method was deduced to obtain the variation rule of the shear buckling load. A good agreement was achieved among the experiment, theoretical analysis, and FEM results. It can be concluded that the theoretical analysis method is relatively conservative, and the FEM is more accurate in case of deformation and strain. The results predicted by h element and p element methods are very close. The results of the study could provide data support for the comprehensive promotion of the design and application of honeycomb sandwich composites.

Experiments on the Buckling of Simply-Supported Rectangular Plates

1969 ◽  
Vol 73 (703) ◽  
pp. 607-608 ◽  
Author(s):  
A. C. Mills
Keyword(s):  
Experimental Investigation ◽  
Theoretical Analysis ◽  
Boundary Conditions ◽  
Buckling Load ◽  
Theoretical Solution ◽  
Rectangular Plates ◽  
Uniform Load ◽  
Simply Supported

In ref. (1) Pope presents a theoretical analysis of the buckling of rectangular plates tapered in thickness under uniform load in the direction of taper. An experimental investigation into the end load buckling problem for a plate having simply-supported edges with the sides prevented from moving normally in the plane of the plate is described in ref. (2). For these boundary conditions the theoretical solution is exact. However, the compatability equation is not satisfied exactly when the sides are free to move in the plane of the plate. This experimental investigation demonstrates that the buckling load is nevertheless adequately predicted by the analysis in these circumstances.

Interaction of 5-S-cysteinyl-dopamine with graphene oxide: an experimental and theoretical study for the detection of a Parkinson's disease biomarker

2019 ◽  
Vol 43 (40) ◽  
pp. 15861-15870 ◽  
Author(s):  
Isidro Badillo-Ramírez ◽  
Bruno Landeros-Rivera ◽  
Emmanuel de la O-Cuevas ◽  
Rubicelia Vargas ◽  
Jorge Garza ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Raman Spectroscopy ◽  
Parkinson's Disease ◽  
Graphene Oxide ◽  
Theoretical Analysis ◽  
Theoretical Study ◽  
Disease Biomarker

Spectroscopic and theoretical analysis in the adsorption of 5-S-Cys-DA over GO for the development of platform biosensors with Raman spectroscopy.

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