Mechanical Analysis of Fracturing String with Double Packers in Horizontal Well

2013 ◽  
Vol 325-326 ◽  
pp. 800-803
Author(s):  
Zhi Miao Li ◽  
Qian Bei Yue ◽  
Ju Bao Liu
Keyword(s):  
Horizontal Well ◽  
Reaction Force ◽  
Frictional Resistance ◽  
Mechanical Analysis ◽  
Contact Friction ◽  
Curvature Effect ◽  
Technical Problems ◽  
Precise Calculation ◽  
Gap Element ◽  
Space Beam Element

The design and mechanical analysis of fracturing string was one of the key technical problems in fracturing operation. Considering contact friction and curvature effect, contact nonlinear problem of fracturing string was solved by space beam element and multidirectional contact gap element method. Contact state, contact reaction force and corresponding frictional resistance between the fracturing string and borehole or inside casing wall could be accurately described by gap element, which generated less simplification in the mechanical model and more precise calculation of force and deformation. The calculations of field examples has shown that while the distance is 10 m, 20 m or 30 m between two packers of fracturing string, maximum axial sliding displacement of the first packer is 0.19 mm and sliding displacement of the second packer is 11.17mm, 23.78mm , or 36.46 mm. The theory basis is provided for the decision of reasonable distance between two packers.

scholarly journals Crosswise tensile resistance of masonry patterns due to contact friction

2020 ◽  
Vol 476 (2240) ◽  
pp. 20200439
Author(s):  
Shipeng Chen ◽  
Katalin Bagi
Keyword(s):  
Failure Modes ◽  
Frictional Resistance ◽  
Discrete Element ◽  
Mechanical Analysis ◽  
Contact Friction ◽  
Tensile Stresses ◽  
Material Parameters ◽  
Masonry Domes ◽  
Zero Resistance ◽  
Discrete Element Simulations

The presented research focuses on masonry shells with dry (cohesionless) contacts. In the mechanical analysis of such structures, the material is often assumed to have zero resistance to tension. This simplification can be questioned in light of the fact that due to the frictional resistance between masonry layers compressed to each other, significant tension can be carried perpendicularly to the direction of the compression. The effect can be so considerable that the typical orange-slice cracking of masonry domes can be prevented purely by choosing a suitable brick shape and bond pattern. Based on preliminary 3DEC discrete element simulations with realistic and experimentally validated material parameters in order to understand the failure modes, the phenomenon is quantified in the present paper for the two main types of bond patterns applied in masonry shells: (i) different versions of the running bond pattern, and (ii) two versions of the herringbone pattern. The theoretically predicted failure tensile stresses are checked and validated with 3DEC discrete element simulations.

On the Existence of a Solution for a Solid Circular Plate Bilaterally Supported Along Two Antipodal Boundary Arcs and Loaded by a Central Transverse Concentrated Force

2000 ◽  
Vol 68 (5) ◽  
pp. 809-812 ◽  
Author(s):  
G. Monegato ◽  
A. Strozzi
Keyword(s):  
Circular Plate ◽  
Plate Theory ◽  
Reaction Force ◽  
Mechanical Analysis ◽  
Square Root ◽  
Existence Of A Solution ◽  
Concentrated Force ◽  
Boundary Constraints ◽  
Title Problem ◽  
The One

A purely flexural mechanical analysis is presented for a thin, solid, circular plate, deflected by a central transverse concentrated force, and bilaterally supported along two antipodal periphery arcs, the remaining part of the boundary being free. This problem is modeled in terms of a singular integral equation of the Prandtl type, which possesses a unique solution expressed in terms of a reaction force containing a factor exhibiting square root endpoint singularities. This solution is then shown not to respect the requested boundary constraints. It is therefore concluded that, within the framework of the purely flexural plate theory, the title problem cannot admit the weighted L2 solution here examined. It cannot, however, be excluded that a solution to the title problem exists, which possesses stronger endpoint singularities than those examined in this paper, or is of a more general form than the one considered here.

Study on Drilling and Completion Techniques of Horizontal well for Coalbed Methane

2014 ◽  
Vol 513-517 ◽  
pp. 2586-2589 ◽  
Author(s):  
Xin Feng Du ◽  
Yong Zhe Zhao
Keyword(s):  
Coal Seam ◽  
Coalbed Methane ◽  
Horizontal Well ◽  
Horizontal Wells ◽  
Mining Area ◽  
Variable Density ◽  
Technical Problems ◽  
Development Direction ◽  
Drilling Technology ◽  
The Many

Due to the unique reservoir characteristics of the coalbed methane (CBM) in China, many technical problems have to be studied and solved in the development of horizontal wells for CBM. In this paper, based on the V-type wells, we have summarized the many techniques involved in Drilling and completion of horizontal well for CBM in Binchang mining area, such as leakage protection and sealing, geosteering while drilling, remote connection, variable density cementing, Coal seam cavitation, fiberglass casing running into the well, and etc. It is pointed out that the air foam under-balance drilling will be the development direction for coalbed methane drilling technology.

A methodology to develop a patient-specific 3D musculoskeletal model based on MRI, ground reaction forces and motion capture data

2015 ◽  
Vol 6 (2) ◽  
pp. 5
Author(s):  
Arnaud Van Branteghem ◽  
Jan Victor ◽  
Patrick De Baets ◽  
Matthias Verstraete
Keyword(s):  
Motion Capture ◽  
Reaction Force ◽  
3D Models ◽  
Lower Limbs ◽  
Patient Specific ◽  
Knee Prostheses ◽  
Replacement Surgery ◽  
Precise Calculation ◽  
Musculoskeletal Models ◽  
Total Knee

The well-documented dissatisfaction of patients with the results of their total knee replacement surgery has been the incentive for deeper research into the optimisation of knee prostheses. One way to optimise total knee replacements is to develop patient-specific 3D musculoskeletal models, enabling a better understanding of the kinematics and kinetics affecting the lower limbs of the patient. This paper suggests a particular methodology to build such personalised models, by implementing data of additional measurement systems. MRI scanning ensures a morphological match between the model and the patient. Additionally, ground reaction force measurements coupled with motion capture provide the kinematic input. A squat test was performed to illustrate the usefulness of the data obtained through the force plates. The combination of this data into the 3D models allows for a more precise calculation and simulation of knee joints. This will ultimately improve the quality of prosthesis testing in a knee-rig setup by providing more accurate boundary conditions.

scholarly journals Exploring Filling Law of Small Fillet of Dual Clutch Hub

2018 ◽  
Vol 36 (3) ◽  
pp. 464-470
Author(s):  
Yilei Zhang ◽  
Zhili Hu ◽  
Jin Li ◽  
Mingliang Dai
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Bp Neural Network ◽  
Frictional Resistance ◽  
Mechanical Analysis ◽  
Geometric Parameters ◽  
Experimental Result ◽  
Forming Quality ◽  
Concave Shape ◽  
Multi Objective Genetic Algorithm

In extruding the dual clutch hub with small fillet gear, the filling of small fillet gear is not complete due to the large forming resistance. A method of preforming the blank into a concave shape is proposed. The mechanical analysis and finite element simulation are used to analyze the principle that the blank of concave shape can promote the filling of small fillet gear, stamping and extruding are both used to form the dual clutch hub and the preform is used to simulate the fillet gear’s extruding to analyze the influence of the geometric parameters of the preform on the forming quality. The mapping relationship between the geometric parameters of the preform and the size of unfilled fillet gear is established by using the BP neural network. The multi-objective genetic algorithm is used to optimize the geometric parameters of the preform. From the results we can see that the frictional resistance decreases due to reduced contact area between the blank and the mold when the section shape of the blank is concave, and at the same time, the tangential thrust is generated on the blank, so the filling of small fillet gear is better; BP neural network combined with genetic algorithm can reliably optimize the geometric parameters of the preform. The filling performance of the fillet gear is better under the optimal preform, and the forming quality of the dual clutch hub is improved. The experimental result verified the feasibility of the method and the accuracy of the simulation.

scholarly journals The Design of Oil Well Downhole Mechanical Analysis System

2014 ◽  
Vol 8 (1) ◽  
pp. 190-196
Author(s):  
Panpan Zhao ◽  
Xiufang Wang ◽  
Ying Liu ◽  
Mengmeng Wu
Keyword(s):  
Production Process ◽  
Rapid Development ◽  
Frictional Resistance ◽  
Mechanical Analysis ◽  
Oil Field ◽  
Oil Well ◽  
Accurate Analysis ◽  
Well Production ◽  
Analysis System ◽  
Scheme Selection

With the rapid development of drilling technology, borehole has become increasingly complex demanding higher standards for downhole operation. The downhole mechanical analysis is an important part of the oil well production analysis. It is very important for the process of drilling, completion and work over operations. The previous operation based on experience has been unable to meet the modern production requirement in accuracy. For the present situation of oil field information construction and the problems being confronted in the production process, this paper designs and implements the downhole mechanical analysis system based on .NET. This system can provide quick and accurate analysis results of downhole string in the process of well production and can also provide the basis for equipment selection and scheme selection in the production process. The design of this system mainly includes two parts: part one consists of the analysis of the deformation to the tubular column with the packer and the other part comprises of the analysis of frictional resistance of tubular column. This system has the advantages of simple operation, accurate calculation, clear analytical results and comprehensive analysis.

Mechanical Analysis of Three Kinds of Beams on Non-Linear Elastic Foundation Materials

2016 ◽  
Vol 867 ◽  
pp. 147-151
Author(s):  
Xiao Liang Chen ◽  
Zuan Tian ◽  
Jian Ping Ding
Keyword(s):  
Elastic Foundation ◽  
Reaction Force ◽  
Internal Force ◽  
Mechanical Analysis ◽  
Linear Elastic ◽  
Non Linear ◽  
Cubic Polynomial ◽  
Internal Forces ◽  
Newton Iteration Method ◽  
Relative Errors

The deformation and internal forces of beams on non-linear elastic foundation materials were studied. The reaction force between the beam and the foundation was fitted as a cubic polynomial about the deflection of beams by experimental data, and the corresponding control equations were derived by the finite difference method. MATLAB program with the Newton iteration method was used to obtain numerical results. Results of the numerical example show the deformation and internal force of short non-linear and linear elastic Winkler beams are same, but the relative errors can reach 10%-20% for moderate and long beams, so the non-linear foundation effect on the settlement of beams should be considered in engineering; the relative errors of the deformation and internal force between moderate non-linear and linear elastic Winkler beams vary with the length of beams, but keep invariant for long beams.

A MODIFIED COMPLETE NORMAL CONTACT STIFFNESS MODEL OF A FRACTAL SURFACE CONSIDERING CONTACT FRICTION

Fractals ◽  
2020 ◽  
Vol 28 (05) ◽  
pp. 2050081
Author(s):  
CHUNLING WEI ◽  
HUA ZHU ◽  
SHIHUI LANG
Keyword(s):  
Contact Stiffness ◽  
Fractal Dimensions ◽  
Frictional Resistance ◽  
Contact Model ◽  
Contact Friction ◽  
Fractal Surface ◽  
Normal Contact ◽  
Stiffness Model ◽  
Fractal Roughness ◽  
Normal Contact Stiffness

This paper presents a modified complete normal contact stiffness model of a fractal surface considering contact friction. We use this model to study the influence of fractal dimensions and fractal roughness on normal contact stiffness. The fractal micro-contact model of an asperity and the complete length scale contact model of fractal surface (both contrasting classical mechanics) are revised. The influence of frictional resistance at micro-contact interfaces on normal contact stiffness is also considered. Predictions of the new model are found to be in greater agreement with the results of the experiments than the predictions of the original model. The study analyzes the influence of fractal dimensions and fractal roughness on the normal contact stiffness. With the increase of these two fractal parameters, their influences on the normal contact stiffness are opposite and are different under high pressure and low pressure.

scholarly journals Calculation of the Dynamic Characteristics of Ship’s Aft Stern Tube Bearing Considering Journal Deflection

2020 ◽  
Vol 27 (1) ◽  
pp. 107-115
Author(s):  
Hongjun Yang ◽  
Jun Li ◽  
Xiaolong Li
Keyword(s):  
Film Thickness ◽  
Dynamic Characteristics ◽  
Dynamic Properties ◽  
Reaction Force ◽  
Vertical Direction ◽  
Finite Width ◽  
Oil Film ◽  
Precise Calculation ◽  
Shaft Alignment ◽  
Favorable Conditions

AbstractDynamic properties are vital for the working reliability of aft stern tube bearings. However, the determination of such properties currently involves several simplifications and assumptions. To obtain its dynamic characteristics accurately, the aft stern tube bearing was divided into several bearing segments. The oil film reaction force was considered in the calculation of shaft alignment, and the journal deflection and actual oil film thickness were obtained accordingly. Subsequently, the perturbed Reynolds equation was solved using the finite difference method when the dynamic characteristics of journal bearings with finite width were evaluated. Then, a calculation program was developed and verified by comparing with the results of other studies. Finally, the dynamic characteristics were calculated under different revolutions. The results showed that the stiffness at the vertical direction of the aft stern tube bearing was several times that of the horizontal direction and varied with the revolutions of the shafting system. These findings can provide the foundation for the precise calculation of the journal trajectory under dynamic conditions, as well as for the evaluation of the oil film thickness. Moreover, the results led to favorable conditions for the accurate calculation of the shafting whirling vibration.

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