scholarly journals The Impact of Rheology on the Transition From Stick‐Slip to Creep in a Semibrittle Analog

2019 ◽  
Vol 124 (3) ◽  
pp. 3144-3154 ◽  
Author(s):  
T. Birren ◽  
J. E. Reber
Keyword(s):  
Stick Slip ◽  
The Impact

scholarly journals Kinematics and dynamics analysis of new rotary-percussive PDM drilling tool

2021 ◽  
pp. 146134842198915
Author(s):  
Jialin Tian ◽  
Xuehua Hu ◽  
Liming Dai ◽  
Lin Yang ◽  
Yi Yang ◽  
...  
Keyword(s):  
Drill String ◽  
Structure Design ◽  
Drilling Process ◽  
Analysis Model ◽  
Drilling Tool ◽  
Stick Slip ◽  
Rate Of Penetration ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
The Impact

This paper presents a new drilling tool with multidirectional and controllable vibrations for enhancing the drilling rate of penetration and reducing the wellbore friction in complex well structure. Based on the structure design, the working mechanism is analyzed in downhole conditions. Then, combined with the impact theory and the drilling process, the theoretical models including the various impact forces are established. Also, to study the downhole performance, the bottom hole assembly dynamics characteristics in new condition are discussed. Moreover, to study the influence of key parameters on the impact force, the parabolic effect of the tool and the rebound of the drill string were considered, and the kinematics and mechanical properties of the new tool under working conditions were calculated. For the importance of the roller as a vibration generator, the displacement trajectory of the roller under different rotating speed and weight on bit was compared and analyzed. The reliable and accuracy of the theoretical model were verified by comparing the calculation results and experimental test results. The results show that the new design can produce a continuous and stable periodic impact. By adjusting the design parameter matching to the working condition, the bottom hole assembly with the new tool can improve the rate of penetration and reduce the wellbore friction or drilling stick-slip with benign vibration. The analysis model can also be used for a similar method or design just by changing the relative parameters. The research and results can provide references for enhancing drilling efficiency and safe production.

Resolving the Unique Invariant Slip-Direction in Rigid Three-Dimensional Multi-Point Impacts at Stick-Slip Transitions

2018 ◽  
Author(s):  
Abhishek Chatterjee ◽  
Alan Bowling
Keyword(s):  
Single Point ◽  
Three Dimensional ◽  
Impact Behavior ◽  
Slip Direction ◽  
Stick Slip ◽  
Impact Forces ◽  
Post Impact ◽  
Impact Problems ◽  
Slip Transition ◽  
The Impact

This work presents a new approach for resolving the unique invariant slip direction at Stick-Slip Transition during impact. The solution method presented in this work is applicable to both single-point and multi-point impact problems. The proposed method utilizes rigid body constraints to resolve the impact forces at all collision points in terms of a single independent impact forces parameter. This work also uses an energetic coefficient of restitution to terminate impact events, thereby yielding energetically consistent post-impact behavior.

scholarly journals Experimental Study on Axial Impact Mitigating Stick-Slip Vibration with a PDC Bit

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Yong Wang ◽  
Hongjian Ni ◽  
Yiliu (Paul) Tu ◽  
Ruihe Wang ◽  
Xueying Wang ◽  
...  
Keyword(s):  
Impact Force ◽  
Impact Load ◽  
Similarity Theory ◽  
Impact Frequency ◽  
Stick Slip ◽  
Axial Impact ◽  
Pdc Bit ◽  
Fluctuation Amplitude ◽  
Rotary Speed ◽  
The Impact

Stick-slip vibration reduces the drilling rate of penetration, causes early wear of bits, and threatens the safety of downhole tools. Therefore, it is necessary to study suppression methods of stick-slip vibration to achieve efficient and safe drilling. Field tests show that the use of downhole axial impactors is helpful to mitigate stick-slip vibration and improve rock-breaking efficiency. However, there are many deficiencies in the study of how axial impact load affects stick-slip vibration of a PDC bit. In this paper, based on the two-degrees-of-freedom spring-mass-damper model and similarity theory, a laboratory experiment device for suppressing stick-slip vibration of a PDC bit under axial impact load has been developed, and systematic experimental research has been carried out. The results show that the axial impact force can suppress the stick-slip vibration by reducing the amplitude of weight on bit and torque fluctuations and by increasing the main frequency of torque. The amplitude of impact force affects the choice of the optimal back-rake angle. The impact frequency is negatively correlated with the fluctuation amplitude of the rotary speed. When the impact frequency is greater than 100 Hz, the fluctuation amplitude of the rotary speed will not decrease.

scholarly journals Drillstring Failure: Analytical and Experimental Approach

2019 ◽  
Vol 300 ◽  
pp. 04004
Author(s):  
Edris Hassan ◽  
Jamil Abdo ◽  
Jan Kwak ◽  
Abdullah Al Shabibi
Keyword(s):  
Torsional Vibration ◽  
Oil And Gas ◽  
Drill Pipe ◽  
Oil And Gas Industry ◽  
Drill String ◽  
Design Parameters ◽  
Experimental Investigations ◽  
Torsional Vibrations ◽  
Stick Slip ◽  
The Impact

Drilling is one of the costliest activities in oil and gas industry due to the complexity of interactions with downhole rock formation. Under such conditions, the uncertainty of drillstring behaviour increase and hence it becomes difficult to predict the causes, occurrences, and types of failures. Lateral and torsional vibrations often cause failure of Bottom Hole Assembly (BHA), drillstring failure, drill bit and wall borehole damages. In this work, a model is presented to determine the impact of lateral and torsional vibrations on a drillstring during the drilling operation. The model aims to mimic real drillstring behaviour inside a wellbore with regards to its dynamic movements due to multiple real situations such as eccentricity of collars, drill pipe sections, and stick-slip phenomena occurring due to the interaction of the bit and the drillstring with the well formation. The work aims to develop a basis for determining critical operating speeds and design parameters to provide safe drilling procedures and reduce drill string fatigue failure. Lagrangian approach is used in this study to attain drillstring lateral and torsional vibration coupling equations. The nonlinear equations are solved numerically to obtain the response of the system. In this work, we also present a brief description of an in-house constructed experimental setup. The setup has the capability to imitate the downhole lateral and torsional vibration modes. Parameters from the experimental investigations are incorporated for validation of the mathematical models and for prediction of the drillstring fatigue life. Such investigations are essential for oil and gas industries as they provide solutions and recommendations about operational speed, lateral and torsional amplitudes measurements and corrections, and the conditions for avoiding occurrence of natural frequencies of the system.

Modelling the source of glacial earthquakes for a better understanding of the impact of iceberg capsize on glacier stability

2020 ◽  
Author(s):  
Pauline Bonnet ◽  
Vladislav Yastrebov ◽  
Alban Leroyer ◽  
Patrick Queutey ◽  
Anne Mangeney ◽  
...  
Keyword(s):  
Mass Loss ◽  
Fluid Structure Interaction ◽  
Greenland Ice Sheet ◽  
Stick Slip ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Dynamic Mass ◽  
Glacier Terminus ◽  
Glacier Dynamics ◽  
The Impact

<p>One current concern in climate science is the estimations of the amount of ice loss by glaciers each year and the corresponding rate of sea level rise. Greenland ice sheet contribution is significant with about 30% to the global ice mass losses. Ice loss in Greenland is distributed approximately equally between loss in land by surface melting and loss at the front of marine-terminating glaciers that is modulated by dynamic processes. Dynamic mass loss includes both submarine melting and iceberg calving. The processes that control ablation at tidewater glacier termini, glacier retreat and calving are complex, setting the limits to the estimation of dynamic mass loss and the relation to glacier dynamics. It involves interactions between bedrock – glaciers – icebergs – ice-mélange – water – atmosphere. Moreover, the capsize of cubic kilometer scale icebergs close to a glacier front can destabilize the glacier, generate tsunami waves, and induce mixing of the water column which can impact both the local fauna and flora.</p><p>We aim to improve the understanding of iceberg capsize using a mechanical modeling of iceberg rotation against the glacier terminus, constrained by the generated seismic waves that are recorded at teleseismic distances. To achieve this objective, we develop a fluid-structure interaction model for the capsizing iceberg. Full scale fluid-structure interaction models enable accurate simulation of complex fluid flows in presence of rigid or deformable solids and in presence of free surfaces. However, such models are computationally very expensive. Therefore, our strategy is to construct a simple solid dynamics model involving contact and friction, whose simplified interaction with water is governed by parametrized forces and moments. We fine tune these parametrized effects on an iceberg capsizing in contact with a glacier with the help of reference direct numerical simulations of fluid-structure interactions involving full resolution of Navier-Stokes equations. We assess the sensitivity of the glacier dynamics to the glacier-bedrock friction law and the conditions for triggering a stick-slip motion of the glacier due to iceberg capsize. The seismogenic sources of the capsizing iceberg in contact with a glacier simulated with our model are then compared to the recorded seismic signals for well documented events.</p>

Consistent VIV Assessment Methodology for Unbonded Flexible Risers

2017 ◽  
Author(s):  
Faycal Ferdi ◽  
Marco Puliafito ◽  
Neil Willis
Keyword(s):  
Energy Loss ◽  
Fatigue Damage ◽  
Bending Stiffness ◽  
Operating Conditions ◽  
Critical Parameters ◽  
Assessment Methodology ◽  
Stick Slip ◽  
Modal Damping ◽  
Flexible Risers ◽  
The Impact

One main objective of assessing vortex-induced vibration (VIV) in deep-water (1000 m) riser design analysis is to determine the VIV fatigue damage. Whilst the VIV assessment methodology is well known for steel catenary risers, the unbonded flexible risers require special attention due to their complex composite behaviour. This is especially true when using the superposition modal approach, which is used in Shear7. The VIV response of unbonded flexible risers when modelled by Shear7 is complex and depends on several parameters, mainly: bending stiffness, modal damping and riser configuration. Flexible risers exhibit a non-linear moment response due to the stick/slip hysteresis phenomena of the metallic wires. For low curvatures, a flexible pipe is characterised by a high bending stiffness. However, when the applied loads exceed a threshold level given by the friction resistance between the layers, slippage between the layers occur and the corresponding bending stiffness is significantly reduced, which leads to higher curvature levels. This behaviour is characterised by the moment-curvature response, which is specific to each cross section and is highly dependent on operating conditions (pressure, temperature), external conditions (temperature and hydrostatic pressure) and riser configuration (tension distribution). The objective of this paper is to establish a consistent VIV analysis methodology for unbonded flexible risers taking some of the main critical parameters such as bending stiffness, modal damping, riser configuration and environmental loading into account. This methodology has been developed for a large West African offshore project, where different types of flexible risers with different operating conditions have been assessed. The impact of the pre-slip and post-slip bending stiffness on the VIV response has been studied and an energy-based approach has been used to calculate the modal damping associated with the frictional energy loss due to the stick/slip phenomenon. This energy loss is directly dependent on the curvatures extracted from the modes excited by the oceanic currents acting on the risers. Different riser configurations have also been considered to assess the impact of the vessel offset on the VIV curvature response. Finally, VIV induced fatigue damage of the flexible risers has been determined using both extreme and long term current profiles assuming steady state current in the VIV model. The fatigue damage has been calculated at several critical locations along each flexible riser by converting the curvature histograms obtained from the VIV assessment into stresses using specific S-N data converting stress cycles into aggregated damage benchmarked against wave-induced damage.

Development of a high-frequency torsional impact generator for improving drilling efficiency

2013 ◽  
Vol 228 (11) ◽  
pp. 1968-1977 ◽  
Author(s):  
Xiaohua Zhu ◽  
Liping Tang
Keyword(s):  
High Frequency ◽  
Oil And Gas ◽  
Impact Frequency ◽  
Element Analysis ◽  
Stick Slip ◽  
Deep Wells ◽  
Experimental Apparatus ◽  
The Finite Element Analysis ◽  
Drilling Technology ◽  
The Impact

The drilling of deep wells has to face problems to suppress stick-slip vibrations, especially for tough formations. Such problems induce frequent tool failures and poor well quality. Torsional impact drilling is an emerging drilling technology for improving the productivity of oil and gas by mitigating the stick-slip vibration. In this paper, a high-frequency torsional impact generator has been developed in order to investigate this drilling technology. Mechanism of torsional impact as a means of stick-slip mitigation is studied. Structure and operating principle of the tool have been presented. The finite element analysis approach is utilized in the analysis of applicability of the impact unit which is most significant for the tool. The analysis indicates that the impact unit operates successfully. An experimental apparatus is developed to examine the applicability of the proposed numerical method to the analysis of the impact unit. Laboratory tests with different impact frequency are conducted with the apparatus. It is verified that the impact system operates regularly, and high-frequency torsional impacts are generated. In addition, impact parameters of the apparatus which will be helpful to the study of the high-frequency torsional impact drilling are obtained.

Study of the Stick-Slip Transition of Newton’s Cradle With Friction

2013 ◽  
Author(s):  
Adrian Rodriguez ◽  
Alan Bowling
Keyword(s):  
Impact Behavior ◽  
Multiple Point ◽  
Stick Slip ◽  
Kinematic Relationship ◽  
Short Time Span ◽  
Post Impact ◽  
Newton’S Cradle ◽  
Six Degree Of Freedom ◽  
Slip Transition ◽  
The Impact

This work uses a new discrete approach to analyze the stick-slip transition of Newton’s cradle with frictional contact. The consideration of friction here leads to a simultaneous, multiple point, indeterminate collision. This work strictly adheres to the assumptions of rigid body modeling in conjunction with the notion that the configuration of the system are constant in the short time span of the collision, which enforces a kinematic relationship between the impact points. The post-impact velocities are determined by using the work-energy relationship of a collision and an energetic coefficient of restitution (ECOR) to model energy dissipation. A three and six degree-of-freedom (DOF) model of the system is considered in this work to examine the stick-slip transition and simulate the post-impact behavior. Simulations are conducted for each model using different coefficients of friction (COFs). The results obtained are compared to theoretical and experimental results reported in other works.

Impacts With Friction: Theory and Experiments

1999 ◽  
Author(s):  
Friedrich Pfeiffer
Keyword(s):  
Tangential Direction ◽  
Impact Machine ◽  
Stick Slip ◽  
Expansion Phase ◽  
Friction Theory ◽  
Frictional Losses ◽  
Industry Applications ◽  
The Impact ◽  
Theory And Experiments ◽  
Impacts With Friction

Abstract Various models for impacts with friction have been proposed, the most successful ones taking into consideration a compression and an expansion phase in normal and tangential direction. Impulses are stored during compression and released with frictional losses during expansion. Stick-slip and detachment phenomena during the impact can be considered by complementarity rules. A corresponding model for impacts with friction is presented and verified by measurements with an impact machine. In addition, some industry applications confirm the theory.

A Simple Dynamic Model For Simulating Draft-Gear Behavior In Rail-Car Impacts

1978 ◽  
Vol 100 (4) ◽  
pp. 492-496 ◽  
Author(s):  
T.-K. Hsu ◽  
D. A. Peters
Keyword(s):  
Dynamic Model ◽  
Static Friction ◽  
Full Scale ◽  
Stick Slip ◽  
Drop Hammer ◽  
Draft Gear ◽  
The Individual ◽  
The Impact ◽  
Good Agreement

A new, simple dynamic model is developed for use in simulating draft-gear behavior in rail-car impacts. The model is based on an analysis of the individual components inside several types of draft gears. The transition from kinetic to static friction during the impact is included. Comparisons with drop-hammer tests and full-scale impacts show good agreement with the experimental forces and deflections. In particular two very important phenomena are correctly simulated: 1) the rise in force just before maximum travel, and 2) the stick-slip-grab phenomenon during impact.

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