Boundary Conditions: A Key Factor in Tubular-String Buckling

SPE Journal ◽  
2015 ◽  
Vol 20 (06) ◽  
pp. 1409-1420 ◽  
Author(s):  
Wenjun Huang ◽  
Deli Gao ◽  
Shaolei Wei ◽  
Pengju Chen
Keyword(s):  
Potential Energy ◽  
Boundary Conditions ◽  
Axial Force ◽  
Virtual Work ◽  
Bending Moment ◽  
Quantitative Relation ◽  
Energy Principle ◽  
Transition Section ◽  
Minimum Potential Energy Principle ◽  
Helical Buckling

Summary Boundary conditions for tubular-string buckling are divided into two kinds on the basis of the virtual work of the nonaxial force on the boundary conditions of the tubular string—namely, the first and the second kinds of boundary conditions. The first kind of boundary conditions means that the virtual work of no-axial force is zero, and both the conventional pinned and fixed ends belong to this kind. The second kind of boundary conditions means that the virtual work of no-axial force is not zero. Previous studies on tubular-string buckling mainly focus on the first kind but ignore the second kind of boundary conditions. In this paper, the effects of the two kinds of boundary conditions on tubular-string buckling are analyzed. The deflection of a long tubular string constrained in a wellbore is divided into the full helical-buckling section and transition section, whereas the transition section is divided further into the no-contact section and perturbed-helix section. The qualitative corresponding relation between boundary conditions and tubular-string buckling in transition and full helical-buckling sections is clarified. To clarify the quantitative relation between boundary conditions and tubular-string buckling, a general-packer model is proposed to depict the two categories of boundary conditions. With the general-packer model, the general potential energy of the tubular string is deduced. According to the minimum-potential-energy principle, the existence and stability of full helical-buckling solutions are given. The deflections of the tubular string in the no-contact and perturbed-helix sections are deduced with buckling differential equation and beam-column model. The bending moment, shear force, and contact force on the tubular string caused by buckling are also analyzed. The results show that boundary conditions, especially the second kind of boundary conditions, are an important factor that makes the tubular-string buckling problem complex, and this paper provides one source for a deeper understanding of boundary conditions.

Buckling Analysis of Tubular Strings in Horizontal Wells

SPE Journal ◽  
2014 ◽  
Vol 20 (02) ◽  
pp. 405-416 ◽  
Author(s):  
Wenjun Huang ◽  
Deli Gao ◽  
Fengwu Liu
Keyword(s):  
Boundary Conditions ◽  
Axial Force ◽  
Shear Force ◽  
Virtual Work ◽  
Bending Moment ◽  
Horizontal Wells ◽  
Comprehensive Description ◽  
New Model ◽  
First Category ◽  
Second Category

Summary A new buckling equation in horizontal wells is derived on the basis of the general bending and twisting theory of rods. The boundary conditions of a long tubular string are divided into two categories: the sum of the virtual work of bending moment and shear force at the ends of tubular strings is equal to zero, and the sum of the virtual work of bending moment and shear force at the ends is not equal to zero. Buckling solutions under different boundary conditions are obtained by solving the new buckling model. For the boundary conditions of the first category, the buckling solutions are identical with previous results. For the boundary conditions of the second category, the buckling solutions are different from the results under the boundary conditions of the first category. The results indicate that buckling behaviors depend on both the axial force and the boundary conditions. Compared with previous results, buckling solutions of the new model provide a more comprehensive description of tubular-buckling behaviors.

A Global Extremum Principle in Mixed Form for Equilibrium Analysis With Elastic/Stiffening Materials (a Generalized Minimum Potential Energy Principle)

1994 ◽  
Vol 61 (4) ◽  
pp. 914-918 ◽  
Author(s):  
J. E. Taylor
Keyword(s):  
Potential Energy ◽  
Problem Formulation ◽  
Extremum Problem ◽  
Equilibrium Analysis ◽  
Minimum Potential Energy ◽  
Problem Statement ◽  
Energy Principle ◽  
Potential Energy Principle ◽  
Minimum Potential ◽  
Minimum Potential Energy Principle

An extremum problem formulation is presented for the equilibrium mechanics of continuum systems made of a generalized form of elastic/stiffening material. Properties of the material are represented via a series composition of elastic/locking constituents. This construction provides a means to incorporate a general model for nonlinear composites of stiffening type into a convex problem statement for the global equilibrium analysis. The problem statement is expressed in mixed “stress and deformation” form. Narrower statements such as the classical minimum potential energy principle, and the earlier (Prager) model for elastic/locking material are imbedded within the general formulation. An extremum problem formulation in mixed form for linearly elastic structures is available as a special case as well.

Analysis of Assumed Mooring Arrangement for Maritime Class Ship

1968 ◽  
Vol 5 (03) ◽  
pp. 257-266
Author(s):  
John L. Horton ◽  
Raymond A. Yagle
Keyword(s):  
Wind Tunnel ◽  
Potential Energy ◽  
Great Lakes ◽  
Minimum Potential Energy ◽  
Energy Principle ◽  
Wind Tunnel Tests ◽  
Potential Energy Principle ◽  
Minimum Potential ◽  
Minimum Potential Energy Principle

An assumed but routine mooring arrangement for a standard Great Lakes ship--in this case a Maritime Class vessel--is analyzed to ascertain what wind conditions would be sufficient to establish the sequence necessary to cause parting of one line, followed by parting of second and third lines and, finally, by full failure of the mooring arrangement. Wind-tunnel tests on a model of the ship are reviewed, and application of the minimum potential energy principle used in the analysis is illustrated.

Stability Analysis of Slope with Arbitrary Sliding Surface on Multi Strata Using Minimum Potential Energy Principle

2011 ◽  
Vol 250-253 ◽  
pp. 2588-2591 ◽  
Author(s):  
Shu Jie Wen ◽  
You Li ◽  
Xin Chen
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Potential Energy ◽  
Safety Factor ◽  
Sliding Surface ◽  
Minimum Potential Energy ◽  
Energy Principle ◽  
Potential Energy Principle ◽  
Minimum Potential ◽  
Minimum Potential Energy Principle

As a rule,the natural slope is not homogeneous,and its sliding surface is arbitrary. However,the common slope stability analysis methods used to assume shape of sliding surface and slope homogeneity,and the calculation process is so complex that accuracy of results is decreasing.In this study,the potential energy function of sliding body is established for slope with arbitrary sliding surface on multi strata.Using minimum potential energy principle, the displacement of sliding body can be got. Then based on Moore - Coulomb criterion and condition of force equilibrium in the sliding direction, the safety factor can be got directly. Case studies show: ①This slope stability analysis methods is valid.② Different definition of safety factor leads to different analysis result.

Discussions on the Two Properties and Applications of Elastic Deformation and Deformation Energy

2011 ◽  
Vol 250-253 ◽  
pp. 232-237 ◽  
Author(s):  
Zhi Hui Li ◽  
Jun Ping Shi ◽  
An Min Tang
Keyword(s):  
Potential Energy ◽  
Elastic Deformation ◽  
Second Law Of Thermodynamics ◽  
Deformation Energy ◽  
Energy Principle ◽  
Energy Value ◽  
Total Potential ◽  
Distribution Rule ◽  
External Forces ◽  
Minimum Potential Energy Principle

During the process of elastic deformation, based on first law of thermodynamics, deformation energy value equals to the work done by external forces moving through elastic deformation, which can determine the amount of elastic deformation. According to second law of thermodynamics, the true deformation energy value should be the minimum of all possible deformations, which can determine the distribution rule of elastic deformation. From this, it can be realized that there are some problems existed in the derived process of the minimum potential energy principle. The total potential energy of system remains constant in all of possible elastic deformation. Applying the two characteristics of elastic deformation, a few application problems could be solved expediently.

Research on Ship Part Nesting System Based on Energy Principle and Intelligent Optimization

2013 ◽  
Vol 694-697 ◽  
pp. 2771-2774
Author(s):  
Xiang Qiang Zhong ◽  
Li Dong Liang ◽  
Yan Hong Yang
Keyword(s):  
Potential Energy ◽  
Physical Meaning ◽  
Minimum Potential Energy ◽  
Energy Principle ◽  
Intelligent Optimization ◽  
Potential Energy Principle ◽  
Minimum Potential ◽  
Nesting Problem ◽  
Minimum Potential Energy Principle ◽  
Intersection Test

A nesting system based on minimum potential energy principle and intelligent optimization for ship part nesting problem was proposed. Discussing polygon judgment and separation, intersection test and collision problems of ship parts, a kind of polygon overlap detection method was put forward, and contacting process was analyzed by use of envelope rectangle intersection test algorithm; During analyzing ship part nesting process based on minimum potential energy principle and genetic algorithm fusion, basic physical meaning of nesting problem was explained from mechanics. Throng intelligent ship part nesting system verification, the algorithm is feasible, physical meaning is clear; it can realize ship part nesting.

On the Inflation of a Plane Nonlinear Membrane

1974 ◽  
Vol 41 (3) ◽  
pp. 767-771 ◽  
Author(s):  
W. W. Feng ◽  
P. Huang
Keyword(s):  
Potential Energy ◽  
Minimum Potential Energy ◽  
Equilibrium Equations ◽  
Energy Principle ◽  
Strain Energy Density Function ◽  
Total Potential ◽  
Minimum Potential ◽  
Minimum Potential Energy Principle ◽  
Admissible Functions ◽  
Nonlinear Membrane

The deformed configurations of an inflated flat nonlinear membrane are obtained by the minimum potential energy principle. The deformed configurations of the membrane are assumed to be represented by a series of geometric admissible functions with unknown coefficients. The unknown coefficients that minimize the total potential energy of the deformed membrane are determined by Fletcher and Powell’s [1] method. The strain-energy-density function for the numerical calculations is assumed to have the Mooney form. The results for a particular case when the Mooney membrane reduces to the neo-Hookean membrane, agree with the previous results obtained by numerical integration of the corresponding equilibrium equations.

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