Fluid-Hammer Effects on Coiled-Tubing Friction in Extended-Reach Wells

Summary The lateral reach and residual bottomhole-assembly (BHA) loads in extended-reach wells strongly depend on the coiled-tubing (CT) mechanical friction. Detailed CT-friction modeling becomes crucial in the prejob planning stage to ensure successful job predictability. However, current numerical simulators consider constant coefficients of friction (CoFs) that are determined from similar operations without taking into account the effects of the operational and downhole parameters on the CoF for a specific operation. This study outlines the modeling of CT-friction force, CoF, and axial BHA loads depending on the operational and downhole parameters when a fluid-hammer tool is used. Recent theoretical, laboratory, and field data have established how CoF depends on the downhole parameters (Livescu and Wang 2014; Livescu and Watkins 2014; Livescu et al. 2014a, b; Livescu and Craig 2015). Previously, these effects were not considered in the CT numerical models, leading to significant CoF differences among available commercial simulators. For instance, the default CoFs in the current prejob simulations for cased holes, when no lubricant or friction-reducing tools such as fluid-hammer tools and tractors are used, vary between 0.24 and 0.30 or even higher. This makes it extremely difficult to consistently evaluate and compare the friction-reduction effects of lubricants, fluid-hammer tools, and tractors in extended-reach wells, especially when the field operator may be consulting with several service companies that use different commercial force-modeling software. This study presents the CT-force matching and fundamental physics on the basis of modeled fluid forces, including radial forces, drag forces, and, most importantly, pressure forces on the CT-friction forces caused by fluid-hammer tools. Extending the method of characteristics, regularly used for studying pressure pulses in straight pipes, the perturbations method also accounts for the helical shape of the CT. The new CT fluid-hammer model is validated against laboratory data. This rigorous method for calculating the axial BHA load and reduced CT-friction force caused by radial vibrations can be easily implemented in currently available tubing-force analysis (TFA) software for CT operations. This novel approach, which uses detailed CT mechanical-friction modeling to take into account parameters such as temperature, internal pressure, pumping rate, and others, improves predictions for CT reach in lateral wells. These findings broaden the current industry understanding of the CT mechanical friction modeling in extended-reach wells, and show benefits for the industry when considering variable friction modeling in commercial CT simulators.

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Increasing Lubricity of Downhole Fluids for Coiled-Tubing Operations

SPE Journal ◽

10.2118/168298-pa ◽

2014 ◽

Vol 20 (02) ◽

pp. 396-404 ◽

Cited By ~ 25

Author(s):

Silviu Livescu ◽

Steven Craig

Keyword(s):

Laboratory Data ◽

Real Life ◽

Friction Reduction ◽

The Other ◽

Case Histories ◽

Measuring Device ◽

Coiled Tubing ◽

General Terms ◽

Metal On Metal ◽

Offshore Crane

Summary The requirement for intervention operations in long-reach lateral wells continues to grow. In the US, it is not uncommon to be asked to run coiled tubing (CT) in 10,000-ft laterals. In general terms, a 2-in. CT typically has enough weight reserves to perform work to approximately half such a lateral. Even though increasing the CT diameter remains a theoretical option to improve reach, practically, it creates logistical challenges with both road transport and offshore crane-lifting/deck-loading limitations. Although fluid-hammer tools and downhole tractors have extended the reasonable operational range of CT significantly, they also increase circulating pressures and operational complexity. To reach a 10,000-ft lateral, the use of metal-on-metal lubricants will be required to work in conjunction with the other systems. Obviously, the use of lubricants is not new. Typical real-life results of current systems are approximately a 15 to 20% reduction in the coefficient of friction (CoF) from a generic 0.24 to 0.19. Occasionally, one could obtain smaller CoF values in the field. However, these actual results compare poorly to laboratory testing with a high-pressure rotational friction test. An extensive set of laboratory measurements was carried out with a linear-friction measuring device to understand and quantify the mechanical, chemical, and thermal metal-on-metal wet frictional effects. Particular attention was paid to the synergy between lubricants and the other commonly circulated brines and fluid friction reducers. Other tests, such as regained-permeability and aging tests were also performed. Arising from the trials is a new lubricant that reduced the linear CoF by approximately 40 to 60% (0.10 to 0.12) under downhole conditions. Friction reduction of this magnitude is expected to make it feasible to run CT in 10,000-ft laterals without the use of fluid-hammer tools or tractors. The paper details the new testing method, technical background of frictional drag, existing lubricant case histories, the new laboratory data, details of compatibility tests, and two new-lubricant case histories.

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Identification of the Effect of Ultrasonic Friction Reduction in Metal-Elastomer Contacts Using a Two-Control-Loop Tribometer

Applied Sciences ◽

10.3390/app11146289 ◽

2021 ◽

Vol 11 (14) ◽

pp. 6289

Author(s):

Michael Weinstein ◽

Christian Nowroth ◽

Jens Twiefel ◽

Jörg Wallaschek

Keyword(s):

Friction Force ◽

Force Control ◽

Sliding Friction ◽

Dynamic Contact ◽

Friction Reduction ◽

Ultrasonic Frequency ◽

Stick Slip ◽

Friction Forces ◽

Variable Position ◽

Sealing Ring

Pneumatic cylinders are widely used in highly dynamic processes, such as handling and conveying tasks. They must work both reliably and accurately. The positioning accuracy suffers from the stick-slip effect due to strong adhesive forces during the seal contact and the associated high breakaway forces. To achieve smooth motion of the piston rod and increased position accuracy despite highly variable position dynamics, sliding friction and breakaway force must be reduced. This contribution presents a specially designed linear tribometer that has two types of control. Velocity control allows the investigation of sliding friction mechanisms. Friction force control allows investigation of the breakaway force. Due to its bearing type, the nearly disturbance-free detection of stick-slip transients and the dynamic contact behavior of the sliding friction force was possible. The reduction of the friction force was achieved by a superposition of the piston rod’s movement by longitudinal ultrasonic vibrations. This led to significant reductions in friction forces at the rubber/metal interface. In addition, the effects of ultrasonic frequency and vibration amplitude on the friction reduction were investigated. With regard to the breakaway force, significant success was achieved by the excitation. The force control made it possible to identify the characteristic movement of the sealing ring during a breakaway process.

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Influence of Nanoscale Textured Surfaces and Subsurface Defects on Friction Behaviors by Molecular Dynamics Simulation

Nanomaterials ◽

10.3390/nano9111617 ◽

2019 ◽

Vol 9 (11) ◽

pp. 1617 ◽

Cited By ~ 1

Author(s):

Ruiting Tong ◽

Zefen Quan ◽

Yangdong Zhao ◽

Bin Han ◽

Geng Liu

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulation ◽

Friction Force ◽

Copper Substrate ◽

Dynamics Simulation ◽

Textured Surfaces ◽

Friction Forces ◽

Subsurface Structures ◽

Texture Orientation ◽

Subsurface Defects

In nanomaterials, the surface or the subsurface structures influence the friction behaviors greatly. In this work, nanoscale friction behaviors between a rigid cylinder tip and a single crystal copper substrate are studied by molecular dynamics simulation. Nanoscale textured surfaces are modeled on the surface of the substrate to represent the surface structures, and the spacings between textures are seen as defects on the surface. Nano-defects are prepared at the subsurface of the substrate. The effects of depth, orientation, width and shape of textured surfaces on the average friction forces are investigated, and the influence of subsurface defects in the substrate is also studied. Compared with the smooth surface, textured surfaces can improve friction behaviors effectively. The textured surfaces with a greater depth or smaller width lead to lower friction forces. The surface with 45° texture orientation produces the lowest average friction force among all the orientations. The influence of the shape is slight, and the v-shape shows a lower average friction force. Besides, the subsurface defects in the substrate make the sliding process unstable and the influence of subsurface defects on friction forces is sensitive to their positions.

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Motion of masses with asymmetric and symmetric friction. Application to fault sliding

10.5194/egusphere-egu21-3934 ◽

2021 ◽

Author(s):

Rui Xiang Wong ◽

Elena Pasternak ◽

Arcady Dyskin

Keyword(s):

Frictional Force ◽

Normal Load ◽

Power Spectra ◽

Inertial Force ◽

Friction Reduction ◽

Relative Mass ◽

Hydraulic Fractures ◽

Driving Frequency ◽

Stick Slip ◽

Friction Forces

This study analyses a situation when a geological fault contains a section of anisotropic gouge with inclined symmetry axes (e.g. inclined layering), Bafekrpour et al. [1]. Such gouge in a constrained environment induces, under compression, asymmetric friction (different friction forces resisting sliding in the opposite directions). The rest of the gouge produces conventional symmetric friction. A mass-spring model of the gouge with asymmetric and symmetric friction sections is proposed consisting of a mass with asymmetric friction connected through a spring to another mass with symmetric friction. These masses are set on a base subjected to vibration. A parametric analysis is performed on this system. Two distinct characteristic regimes were observed: recurrent movement resembling stick-slip motion similar to predicted by [2] and sub-frictional movement. Recurrent movement arises when the inertial force is sufficient to overcome frictional force of a block with symmetric friction. Sub-frictional movement occurs when the inertial force is not sufficient to overcome frictional force of an equivalent system with only symmetric friction. The sub-frictional movement is produced by the force in the connecting spring increased due to the movement of the asymmetric friction block in the direction characterised by low friction. We formulate the criterion at which sub-frictional movement occurs. The occurrence of sub-frictional depends upon the relative mass of the symmetric and asymmetric friction sections, as well as the amplitude and driving frequency of the excitation. Power spectra of the produced vibrations are determined for both regimes. The results can shed light on mechanisms of sliding over pre-existing discontinuities and their effect on seismic event generation and propagation of hydraulic fractures in the presence of discontinuities.[1] Bafekrpour, E., A.V. Dyskin, E. Pasternak, A. Molotnikov and Y. Estrin (2015), Internally architectured materials with directionally asymmetric friction. Scientific Reports, 5, Article 10732.[2] Pasternak, E. A.V. Dyskin and I. Karachevtseva, 2020. Oscillations in sliding with dry friction. Friction reduction by imposing synchronised normal load oscillations. International Journal of Engineering Science, 154, 103313.Acknowledgement. AVD and EP acknowledge support from the Australian Research Council through project DP190103260.

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Experimental Study of a Variable Pressure Damper on Automotive Valve Motion

Volume 3: 22nd Design Automation Conference ◽

10.1115/96-detc/dac-1052 ◽

1996 ◽

Author(s):

Jin-Jang Liou ◽

Grodrue Huang ◽

Wensyang Hsu

Keyword(s):

Experimental Study ◽

Friction Coefficient ◽

Friction Force ◽

High Speed ◽

Experimental Results ◽

Variable Pressure ◽

Friction Forces ◽

Valve Spring ◽

Valve Motion

Abstract A variable pressure damper (VPD) is used here to adjusted the friction force on the valve spring to investigate the relation between the friction force and the valve bouncing phenomenon. The friction force on the valve spring is found experimentally, and the corresponding friction coefficient is also determined. Dynamic valve displacements at different speeds with different friction forces are calibrated. Bouncing and floating of the valve are observed when the camshaft reaches high speed. From the measured valve displacement, the VPD is shown to have significant improvement in reducing valve bouncing distance and eliminating floating. However, experimental results indicate that the valve bouncing can not be eliminated completely when the camshaft speed is at 2985 rpm.

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Mathematical Modeling of Impact of Possible Shock Dynamic Loads on the Modern Composite Materials

EPJ Web of Conferences ◽

10.1051/epjconf/201922402012 ◽

2019 ◽

Vol 224 ◽

pp. 02012

Author(s):

Eugenе Sosenushkin ◽

Oksana Ivanova ◽

Elena Yanovskaya ◽

Yuliya Vinogradova

Keyword(s):

Composite Materials ◽

Friction Force ◽

Equations Of Motion ◽

Elastic Fiber ◽

Dynamic Loads ◽

Friction Forces ◽

Absolute Value ◽

A Value ◽

The Absolute ◽

The Impact

In this paper, we study the dynamic processes in materials reinforced with fibers, that can be represented as composite rods. There has been developed a mathematical model of wave propagation under the impact of a shock pulse in semi-infinite composite rods. It is believed that the considered composite rod consists of two layers formed by simpler rods of different isotropic materials with different mechanical properties. The cross sections of such rods are considered to be constant and identical. When such composite materials are impacted by dynamic loads, a significant part of the energy is dissipated due to the presence of friction forces between the contact surfaces of the rods. In this regard, we study the propagation of waves in an elastic fiber-rod, the layers of which interact according to Coulomb law of dry friction. The case of instantaneous excitation of rods by step pulses is investigated. The blow is applied to a rod made of a harder material. In the absence of slippage, the friction force gets a value not exceeding the absolute value of the limit. In the absence of slippage, the friction force takes a value not exceeding the absolute value of the limit. Let us consider the value of the friction force constant. Normal stresses and velocities satisfy the equations of motion and Hooke’s law. The problem statement results in the solution of inhomogeneous wave equations by the method of characteristics in different domains, which are the lines of discontinuities of the solution. Solutions are found in all constructed domains. On the basis of the analysis of the obtained solution, qualitative conclusions are made and curves are constructed according to the obtained ratios. From the found analytical solution of the problem it is possible to obtain ratios for stresses and strain rates in composite rods and composite materials.

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Estimation of Irregular Wave Runup on Intermediate and Reflective Beaches Using a Phase-Resolving Numerical Model

Journal of Marine Science and Engineering ◽

10.3390/jmse8120993 ◽

2020 ◽

Vol 8 (12) ◽

pp. 993

Author(s):

Jonas Pinault ◽

Denis Morichon ◽

Volker Roeber

Keyword(s):

Time Series ◽

Best Practices ◽

Numerical Models ◽

Laboratory Data ◽

Irregular Waves ◽

Wave Transformation ◽

Model Parameters ◽

Wave Runup ◽

Data Set ◽

Promising Alternative

Accurate wave runup estimations are of great interest for coastal risk assessment and engineering design. Phase-resolving depth-integrated numerical models offer a promising alternative to commonly used empirical formulae at relatively low computational cost. Several operational models are currently freely available and have been extensively used in recent years for the computation of nearshore wave transformations and runup. However, recommendations for best practices on how to correctly utilize these models in computations of runup processes are still sparse. In this work, the Boussinesq-type model BOSZ is applied to calculate runup from irregular waves on intermediate and reflective beaches. The results are compared to an extensive laboratory data set of LiDAR measurements from wave transformation and shoreline elevation oscillations. The physical processes within the surf and swash zones such as the transfer from gravity to infragravity energy and dissipation are accurately accounted for. In addition, time series of the shoreline oscillations are well captured by the model. Comparisons of statistical values such as R2% show relative errors of less than 6%. The sensitivity of the results to various model parameters is investigated to allow for recommendations of best practices for modeling runup with phase-resolving depth-integrated models. While the breaking index is not found to be a key parameter for the examined cases, the grid size and the threshold depth, at which the runup is computed, are found to have significant influence on the results. The use of a time series, which includes both amplitude and phase information, is required for an accurate modeling of swash processes, as shown by computations with different sets of random waves, displaying a high variability and decreasing the agreement between the experiment and the model results substantially. The infragravity swash SIG is found to be sensitive to the initial phase distribution, likely because it is related to the short wave envelope.

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Prophylaxis protocols and their impact on bracket friction force

The Angle Orthodontist ◽

10.2319/020119-72.1 ◽

2019 ◽

Vol 89 (6) ◽

pp. 883-888

Author(s):

Sérgio Elias Neves Cury ◽

Silvio Augusto Bellini-Pereira ◽

Aron Aliaga-Del Castillo ◽

Sérgio Schneider ◽

Arnaldo Pinzan ◽

...

Keyword(s):

Sodium Bicarbonate ◽

Qualitative Analysis ◽

Friction Force ◽

Friction Forces ◽

Debris Accumulation ◽

Intergroup Comparison ◽

Group 3 ◽

Group 2 ◽

Sliding Mechanics

ABSTRACT Objective: To evaluate the effect of two different prophylaxis protocols on the friction force in sliding mechanics during in vivo leveling and alignment. Materials and Methods: The sample comprised 48 hemi-arches divided into three groups according to the prophylactic protocol adopted. Group 1 consisted of patients undergoing prophylaxis with sodium bicarbonate, group 2 consisted of patients submitted to prophylaxis with glycine, and group 3 consisted of patients without prophylaxis, as a control. All patients received hygiene instructions and, with the exception of group 3, prophylaxis was performed monthly. After 10 months, the brackets were removed from the oral cavity and submitted to friction force tests and qualitative analysis by scanning electron microscopy. Analysis of variance followed by Tukey tests was performed for intergroup comparison regarding the friction force. Results: The experimental groups presented significantly smaller friction forces than the group without prophylaxis. Accordingly, qualitative analysis showed greater debris accumulation in the group without the prophylactic procedures. Conclusions: Prophylactic blasting with sodium bicarbonate or glycine can significantly prevent an increase of the friction force during sliding mechanics.

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Friction Force Measurements Using the Instantaneous IMEP Method and Comparison With RINGPAK Simulations

ASME 2005 Internal Combustion Engine Division Fall Technical Conference (ICEF2005) ◽

10.1115/icef2005-1300 ◽

2005 ◽

Cited By ~ 1

Author(s):

Myoungjin Kim ◽

Thomas M. Kiehne ◽

Ronald D. Matthews

Keyword(s):

Friction Force ◽

Piston Ring ◽

Cost Effective ◽

Firing Condition ◽

Force Measurements ◽

Connecting Rod ◽

Friction Forces ◽

Bench Tests ◽

Ring Assembly ◽

Analysis System

Even though many researchers have measured the piston/ring assembly friction force over the last several decades, accurate measurement of the piston/ring assembly friction force is a still challenging problem. The floating liner method is not widely used, in spite of its accuracy, due to the substantial modifications required to the engine. On the other extreme, bench tests of the piston/ring assembly cannot completely simulate the real firing condition although bench tests are rapid, consistent, and cost effective. In this study, friction forces of the piston/ring assembly were measured using the instantaneous IMEP method and compared with modeling results using Ricardo’s RINGPAK software. In this research, a flexible flat cable was used to connect the connecting rod strain gage signal to the analysis system instead of using a grasshopper linkage. Therefore, the piston/ring assembly friction force was measured with the minimum change to the engine hardware.

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Linear Friction Damper Consisted of Cylindrical Block and Inclined Lever (Improvement to Avoid Sprag-Slip Problem and Analytical Model to Verify Cause)

ASME 2011 Pressure Vessels and Piping Conference: Volume 8 ◽

10.1115/pvp2011-57073 ◽

2011 ◽

Author(s):

Hideya Yamaguchi ◽

Hidehisa Yoshida

Keyword(s):

Analytical Model ◽

Friction Force ◽

Friction Damper ◽

Friction Forces ◽

Constant Friction ◽

Linear Friction ◽

New Type ◽

Passive Isolation ◽

Isolation Systems ◽

Cylindrical Block

For the passive isolation systems, the ordinary friction damper of constant friction force has performance limitations. This is, because the isolation characteristic declines and the displacement remains apart from the equilibrium position after the disturbance disappears, when the friction force is large. It is known that the above drawbacks are improved when the friction force varies depending on the displacement. The authors have proposed a new type of friction damper in our previous paper. This friction damper uses an inclined lever, which contacts the cylindrical block by means of a rotational spring. The angle of inclination of the lever varies together with the displacement of the cylindrical block. Then, the normal and friction forces on the contact surface vary depending on the displacement. However, “Sprag-slip” vibration occurred in some cases in the experiments. This paper investigates the cause of the vibration and a design to prevent it. Then, an analytical model is proposed to simulate the problem and to estimate the effect of improvement.

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