Analysis of Critical Buckling Loads For Tool-Jointed Drillstrings in Deviated Wellbores

2021 ◽  
Author(s):  
Nnaemeka Princewill Ohia ◽  
Stanley Toochukwu Ekwueme ◽  
Gabriel Ifeanyi Achumba ◽  
Ndubuisi Okechukwu Okereke ◽  
Ifeanyi Valerian Nwankwo ◽  
...  
Keyword(s):  
Compressive Force ◽  
Buckling Loads ◽  
Force Transfer ◽  
Open Hole ◽  
Post Buckling ◽  
Definition Of ◽  
Comparison Of The Results ◽  
Sinusoidal Buckling ◽  
Helical Buckling ◽  
Tool Joint

Abstract Excessive torque and drag, buckling and shear forces on downhole strings and tubulars are often encountered in the drilling of longer reach or deviational wells. Buckling of drillstring and BHA occurs in drillstring mainly due to high compressive forces. A point may be reached where these compressive forces rise and exceed the critical buckling loads leading to buckling of the drillstring/BHA or tubulars. This study focuses on the evaluation of the effect of tool-joint on the buckling of drillstrings for highly deviated wells. Tool-joint in pipes changes the pipes geometry in the wellbore thus affecting its hydraulics, orientation and stress distribution. A notable error will arise when straight pipe (with uniform outside diameter (OD) models are used to model pipes with end couplings and connections (such as tool joints). These errors may impact critical buckling loads, buckling initiation points, and post-buckling analysis of the pipe or BHA, thus affecting the success of drilling and completion operations. Torque and drag simulation and analysis was carried out for drillstring and BHA components in 9 5/8 in casing and 8.5 in open-hole sections to determine buckling loads. Two cases were considered; case 1 investigated the modeling and definition of buckling conditions for single straight body drillstrings and case 2 evaluated the buckling conditions for tool-jointed pipes. The result shows that buckling in tool-jointed pipes follows similar trend to that of straight body pipes with sinusoidal or lateral buckling being initiated first, and gradually progresses to helical buckling on increased axial force transfer. Furthermore, from the comparison of the results from two cases considered, it was observed that the presence tool-joint in the pipes led to a critical buckling load of 5.8% for sinusoidal buckling modes. The paper suggests that higher compressive force is needed to buckle the tool-jointed ends of the drillstring than the straight ends.

Effect of Matching Buckling Loads on Post-Buckling Behavior in Compliant Mechanisms

2021 ◽  
Author(s):  
A. Numić ◽  
T. W. A. Blad ◽  
F. van Keulen
Keyword(s):  
Compliant Mechanisms ◽  
Relative Length ◽  
Optimal Designs ◽  
Element Analysis ◽  
Buckling Loads ◽  
Actuation Force ◽  
Stepped Beam ◽  
Buckling Behavior ◽  
Post Buckling ◽  
Novel Method

Abstract In this paper, a novel method for stiffness compensation in compliant mechanisms is investigated. This method involves tuning the ratio between the first two critical buckling loads. To this end, the relative length and width of flexures in two architectures, a stepped beam and parallel guidance, are adjusted. Using finite element analysis, it is shown that by maximizing this ratio, the actuation force for transversal deflection in post-buckling is reduced. These results were validated experimentally by identifying the optimal designs in a given space and capturing the force-deflection characteristics of these mechanisms.

The Role of Adhesive in the Load Response of Adhesively Bonded Aluminum Hat Sections Under Axial Compression

2001 ◽  
Author(s):  
Jianping Lu ◽  
Golam M. Newaz ◽  
Ronald F. Gibson
Keyword(s):  
Compressive Strength ◽  
Plastic Collapse ◽  
Adhesively Bonded ◽  
Buckling Mode ◽  
Buckling Loads ◽  
Buckling Modes ◽  
Load Response ◽  
Peak Loads ◽  
Post Buckling

Abstract Aluminum hat section, either adhesively bonded or unbonded, experiences buckling, post buckling and plastic collapse when axially compressed. However, there exist obvious differences in the load response between the bonded and unbonded hat sections. Finite element eigenvalue buckling analysis is carried out to predict the buckling load and mode. Experiments show that when adhesively bonded hat sections begin to buckle there is a transformation from the first buckling mode to the higher ones, while the unbonded hat sections develop the post buckling based on the lowest buckling mode. The different buckling modes result in not only different buckling loads but different peak loads of the hat sections as well. Finally, the ultimate compressive strength formulae are proposed for the hat sections.

Delamination Suppression in Sandwich Beams Using Translaminar Reinforcements

1999 ◽  
Author(s):  
Brian T. Wallace ◽  
Bhavani V. Sankar ◽  
Peter G. Ifju
Keyword(s):  
Axial Compression ◽  
Sandwich Beam ◽  
Sandwich Beams ◽  
Thickness Direction ◽  
Compression Tests ◽  
Honeycomb Core ◽  
Element Analysis ◽  
Buckling Loads ◽  
Buckling Behavior ◽  
Post Buckling

Abstract The present study is concerned with translaminar reinforcement in a sandwich beam for preventing buckling of a delaminated face-sheet under axial compression. Graphite/epoxy pins are used as reinforcement in the thickness direction of sandwich beams consisting of graphite/epoxy face-sheets and a Aramid honeycomb core. Compression tests are performed to understand the effects of the diameter of the reinforcing pins and reinforcement spacing on the ultimate compressive strength of the delaminated beams. A finite element analysis is performed to understand the effects of translaminar reinforcement on the critical buckling loads and post-buckling behavior of the sandwich beam under axial compression.

scholarly journals Midcarpal Structure Effect on Force Distribution through the Radiocarpal Joint

2019 ◽  
Vol 08 (06) ◽  
pp. 477-481
Author(s):  
Ronit Wollstein ◽  
Aviv Kramer ◽  
Scott Friedlander ◽  
Frederick Werner
Keyword(s):  
Compressive Force ◽  
Structural Variations ◽  
Level Of Evidence ◽  
Ulnar Deviation ◽  
Level Ii ◽  
Force Transfer ◽  
Radiocarpal Joint ◽  
Flexion Extension ◽  
Tensile Forces ◽  
Midcarpal Joint

Abstract Background Wrist structure is complicated by distinct anatomical patterns. Previous studies defined radiographic wrist types based on lunate and capitate shape within the midcarpal joint. We hypothesized that these disparate structural patterns will transfer forces differently through the wrist. Objective This study aims to correlate force transferred to the distal radius and ulna with morphological measurements in cadaver arms. Methods Radiographs from 46 wrists, previously tested for force transfer between the radius and ulna, were examined. The percentage of compressive force through the distal ulna was determined by mounting load cells to the radius and ulna, while 22.2 Newton (N) tensile forces were individually applied to multiple tendons. Each wrist was tested in a neutral flexion–extension and radial-ulnar deviation position. Results Wrist type and lunate type were associated with percentage of force transfer through the ulna (p = 0.002, p = 0.0003, respectively). Percentage of force transfer was correlated with capitate circumference (p = 0.02, r = 0.34). Conclusions This study supports distinct force transfer between morphological wrist types. Clinical Relevance Understanding the mechanical significance of different structural variations in the wrist bones will improve our ability to understand wrist function and the distinctive development of wrist pathology. Level of Evidence This is a Level II study.

The Buckling Behavior of Pipes and Its Influence on the Axial Force Transfer in Directional Wells

2000 ◽  
Vol 122 (3) ◽  
pp. 129-135 ◽  
Author(s):  
Ergun Kuru ◽  
Alexander Martinez ◽  
Stefan Miska ◽  
Weiyong Qiu
Keyword(s):  
Internal Pressure ◽  
Axial Force ◽  
Current Theory ◽  
Pipe Diameter ◽  
Computer Simulator ◽  
Buckling Behavior ◽  
Force Transfer ◽  
Post Buckling ◽  
Support Conditions ◽  
The University

An experimental setup was built at the University of Tulsa to study buckling and post-buckling behavior of pipes constrained in straight horizontal and curved wellbores. Experiments were conducted to investigate the axial force transfer with and without static internal pressure. Different stages of buckling phenomena and their relation to the axial force, the pipe diameter (1/4 and 3/8 in.) and the pipe end-support conditions have also been investigated. Experimental results have shown that the buckling load is a strong function of the pipe diameter and the pipe end-support conditions. Static internal pressure appears to have insignificant influence on the buckling behavior of pipes. A brief review of recently developed mathematical models to predict buckling behavior of pipes in inclined, curved, and horizontal sections of wellbore is also presented. Applications of the current theory are presented by using recently developed computer simulator. Results of the theoretical analysis have confirmed the versatility and effectiveness of computer simulator for better understanding and solving buckling related problems in the field. [S0195-0738(00)00903-1]

Effects of Friction on Post-Buckling Behavior and Axial Load Transfer in a Horizontal Well

SPE Journal ◽  
2010 ◽  
Vol 15 (04) ◽  
pp. 1104-1118 ◽  
Author(s):  
Guohua Gao ◽  
Stefan Miska
Keyword(s):  
Boundary Conditions ◽  
Critical Load ◽  
Axial Load ◽  
Load Transfer ◽  
Experimental Studies ◽  
Proper Solution ◽  
Buckling Behavior ◽  
Post Buckling ◽  
Helical Buckling ◽  
Lateral Friction

Summary In this paper, the buckling equation and natural boundary conditions are derived with the aid of calculus of variations. The natural and geometric boundary conditions are used to determine the proper solution that represents the post-buckling configuration. Effects of friction and boundary conditions on the critical load of helical buckling are investigated. Theoretical results show that the effect of boundary conditions on helical buckling becomes negligible for a long pipe with dimensionless length greater than 5π Velocity analysis shows that lateral friction becomes dominant at the instant of buckling initiation. Thus, friction can increase the critical load of helical buckling significantly. However, once buckling is initiated, axial velocity becomes dominant again and lateral friction becomes negligible for post-buckling behavior and axial-load-transfer analysis. Consequently, it is possible to seek an analytical solution for the buckling equation. Analytical solutions for both sinusoidal and helical post-buckling configurations are derived, and a practical procedure for modeling of axial load transfer is proposed. To verify the proposed model and analytical results, the authors also conducted experimental studies. Experimental results support the proposed solutions.

Behavior of Thin-Film-Type Delamination of Layered Composite in Post-Buckling

2013 ◽  
Vol 774-776 ◽  
pp. 1312-1321 ◽  
Author(s):  
Vitalijs Pavelko
Keyword(s):  
Compressive Force ◽  
Layered Composite ◽  
Stress And Strain ◽  
Elastic Plates ◽  
Post Buckling ◽  
Complete Elliptic Integrals ◽  
Analysis Of Stability ◽  
Delamination Propagation ◽  
State Stress ◽  
Buckled State

A revision of the basic assumptions those are usually used in the analysis of stability of thin delaminated layer and delamination propagation in a compressed composite is presented in this paper. For this purpose, the theory of flexible elastic plates with large displacements was used. As a result the compressive force and the total longitudinal strain of sub-laminate are expressed in terms of complete elliptic integrals, which uniquely identify the buckled shape of sub-laminate, the effect of buckling on the compression strain and increment of the compressive force in the buckled state. Stress and strain, as well as the strength of the buckled sub-laminate in the dangerous cross-section were also analyzed. The results of the general analysis of delamination propagation and its compression-bending destruction in the buckled state allow to define the basic regularities of the damage behavior of compressed layered composite.

Design Sensitivity of Buckled Thin-Walled Composite Structural Elements

1997 ◽  
Vol 50 (11S) ◽  
pp. S3-S10 ◽  
Author(s):  
Leonel I. Alma´nzar ◽  
Luis A. Godoy
Keyword(s):  
Volume Fraction ◽  
Local Buckling ◽  
Design Sensitivity ◽  
Transverse Load ◽  
Design Parameters ◽  
Structural Elements ◽  
Perturbation Expansions ◽  
Cross Sectional ◽  
Buckling Loads ◽  
Post Buckling

This paper presents a theory and applications to account for changes in the fundamental, buckling, and post-buckling states when design parameters of a composite material are modified. The influence of micro-mechanical parameters (the volume fraction and the fiber orientation) and of cross-sectional dimensions is investigated. A numerical example for columns made of composite materials is presented. Sensitivity is studied for local buckling loads. Explicit expressions are obtained for the sensitivities in the form of perturbation expansions. A beam under transverse load is also investigated, and geometric design parameters employed to investigate sensitivity. The information from the sensitivity analysis can be used to improve a design by modification of the buckling load.

On Buckling Loads of Timoshenko Columns with Elastically Supported Ends

2012 ◽  
Vol 446-449 ◽  
pp. 578-581
Author(s):  
Hua Zhang ◽  
Xiang Fang Li
Keyword(s):  
Lower Bound ◽  
Closed Form ◽  
Upper Bound ◽  
Intermediate State ◽  
Critical Loads ◽  
Compressive Force ◽  
Buckling Loads ◽  
Characteristic Equations ◽  
The Stability ◽  
Elastically Supported

The stability of Timoshenko columns with elastically supported ends under axially compressive force is analyzed. Characteristic equations are obtained according to an intermediate state between Haringx’s and Engesser’s models. For clamped-free, clamped-clamped, and pinned-pinned columns, buckling loads are given in closed form. The influences of elastic restraint stiffness on the critical loads are elucidated. Haringx’s and Engesser’s models are two extreme cases of the present. Critical buckling loads using Haringx’s model are upper bound, and those using Engesser’s model are lower bound.

scholarly journals Helical post-buckling of a rod in a cylinder: with applications to drill-strings

2012 ◽  
Vol 468 (2142) ◽  
pp. 1591-1614 ◽  
Author(s):  
J. M. T. Thompson ◽  
M. Silveira ◽  
G. H. M. van der Heijden ◽  
M. Wiercigroch
Keyword(s):  
Petroleum Industry ◽  
Approximate Solutions ◽  
Drill String ◽  
Elastic Rod ◽  
Continuous Contact ◽  
Axial Tension ◽  
Cylindrical Casing ◽  
Post Buckling ◽  
Universal Graphs ◽  
Helical Buckling

The helical buckling and post-buckling of an elastic rod within a cylindrical casing arises in many disciplines, but is particularly important in the petroleum industry. Here, a drill-string, subjected to an end twisting moment combined with axial tension or compression, is particularly prone to buckling within its bore-hole—with potentially serious results. In this paper, we make a detailed theoretical study of this type of instability, deriving precise new results for the advanced post-buckling stage when the rod is in continuous contact with the cylinder. Results, including rigorous stability analyses and contact pressure assessments, are presented as equilibrium surfaces to facilitate comparisons with experimental results. Two approximate solutions give insight, universal graphs and parameters, for the practically relevant case of small angles, and highlight the existence of a critical cylinder diameter. Excellent agreement with experiments is achieved.

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