Modeling of Coupled Axial and Torsional Motions of a Drilling System

2015 ◽  
Author(s):  
Zheren Ma ◽  
Dongmei Chen
Keyword(s):  
Time Domain ◽  
Drill Pipe ◽  
Propagation Theory ◽  
Stick Slip ◽  
Proposed Model ◽  
Wide Range ◽  
Drilling Operations ◽  
Drilling System ◽  
Rock Bit ◽  
The Impact

During drilling operations, rock-bit interactions may cause a wide range of undesirable system vibrations. The induced vibrations subsequently reduce drilling efficiency and increase fatigue loads acting on drill bit. In this paper, a coupled torsional and axial drilling model is proposed. It can be used to predict the vibrations including bit bounce and stick-slip. Instead of using finite element (FEM) approach, the drill pipe is accurately modeled based on wave propagation theory. This results in time-delay equations in time domain and significantly reduces the computational complexity associated with FEM. The axial and torsional motions are coupled by bit-rock interactions. Different rock-bit interaction conditions are considered based on bit rotation and contact with formation. Simulations are conducted using the proposed model to analyze the impact of different applied weights on bit and surface rotary speeds on the system vibrations. This information provides insights into optimization of drilling operation.

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.

Stick-Slip and Bit-Bounce Interaction in Oil-Well Drillstrings

2006 ◽  
Vol 128 (4) ◽  
pp. 268-274 ◽  
Author(s):  
Ahmet S. Yigit ◽  
Andreas P. Christoforou
Keyword(s):  
Control Strategies ◽  
Operating Conditions ◽  
Oil Well ◽  
Axial Motion ◽  
Stick Slip ◽  
Well Drilling ◽  
Wide Range ◽  
Equipment Failures ◽  
Drilling Operations ◽  
Major Factors

Drillstring vibrations and in particular stick-slip and bit-bounce are detrimental to oil-well drilling operations. Controlling these vibrations is essential because they may cause equipment failures and damage to the oil-well. A simple model that adequately captures the dynamics is used to simulate the effects of varying operating conditions on stick-slip and bit-bounce interactions. It is shown that the conditions at the bit/formation interface, such as bit speed and formation stiffness, are major factors in shaping the dynamic response. Due to the varying and uncertain nature of these conditions, simple operational guidelines or active rotary table control strategies are not sufficient to eliminate both stick-slip and bit-bounce. It is demonstrated that an additional active controller for the axial motion can be effective in suppressing both stick-slip and bit-bounce. It is anticipated that if the proposed approach is implemented, smooth drilling will be possible for a wide range of conditions.

Drillstring Failure—Identification, Modeling, and Experimental Characterization

2019 ◽  
Vol 5 (2) ◽  
Author(s):  
Jamil Abdo ◽  
Edris M. Hassan ◽  
Khaled Boulbrachene ◽  
Jan C. T. Kwak
Keyword(s):  
Torsional Vibration ◽  
Oil And Gas ◽  
Drill Pipe ◽  
Oil And Gas Industry ◽  
Design Parameters ◽  
Experimental Investigations ◽  
Torsional Vibrations ◽  
Stick Slip ◽  
Coupling Equations ◽  
The Impact

Drilling is one of the costliest and risky activities in oil and gas industry due to complexity of interactions with downhole formation. Under such conditions, the uncertainty of drillstring behavior increases, 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 behavior 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 drillstring 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/gas industries as they provide solutions as well as recommendations about operating speed, lateral and torsional amplitudes measurements and corrections, and the conditions for avoiding occurrence of natural frequency(ies) of the system.

scholarly journals Bifurcation analysis of a SEIR epidemic system with governmental action and individual reaction

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Abdelhamid Ajbar ◽  
Rubayyi T. Alqahtani
Keyword(s):  
Transmission Rate ◽  
Dynamical Behavior ◽  
Step Function ◽  
Model Parameters ◽  
Periodic Behavior ◽  
Proposed Model ◽  
Wide Range ◽  
Individual Reaction ◽  
The Impact ◽  
Governmental Action

Abstract In this paper, the dynamical behavior of a SEIR epidemic system that takes into account governmental action and individual reaction is investigated. The transmission rate takes into account the impact of governmental action modeled as a step function while the decreasing contacts among individuals responding to the severity of the pandemic is modeled as a decreasing exponential function. We show that the proposed model is capable of predicting Hopf bifurcation points for a wide range of physically realistic parameters for the COVID-19 disease. In this regard, the model predicts periodic behavior that emanates from one Hopf point. The model also predicts stable oscillations connecting two Hopf points. The effect of the different model parameters on the existence of such periodic behavior is numerically investigated. Useful diagrams are constructed that delineate the range of periodic behavior predicted by the model.

Rock–bit interaction effects on high-frequency stick-slip vibration severity in rotary drilling systems

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chafiaa Mendil ◽  
Madjid Kidouche ◽  
Mohamed Zinelabidine Doghmane ◽  
Samir Benammar ◽  
Kong Fah Tee
Keyword(s):  
High Frequency ◽  
Drill String ◽  
System Stability ◽  
Practical Implementation ◽  
Rotary Drilling ◽  
Stick Slip ◽  
Content Type ◽  
Drilling System ◽  
Rock Bit ◽  
Slip Phenomenon

PurposeThe drill string vibrations can create harmful effects on drilling performance because they generate the stick-slip phenomenon which reduces the quality of drilling and decreases the penetration rate and may affect the robustness of the designed controller. For this reason, it is necessary to carefully test the different rock-bit contact models and analyze their influences on system stability in order to mitigate the vibrations. The purpose of this paper is to investigate the effects of rock-bit interaction on high-frequency stick-slip vibration severity in rotary drilling systems.Design/methodology/approachThe main objective of this study is an overview of the influence of the rock-bit interaction models on the bit dynamics. A total of three models have been considered, and the drilling parameters have been varied in order to study the reliability of the models. Moreover, a comparison between these models has allowed the determination of the most reliable function for stick-slip phenomenon.FindingsThe torsional model with three degrees of freedom has been considered in order to highlight the effectiveness of the comparative study. Based on the obtained results, it has been concluded that the rock-bit interaction model has big influences on the response of the rotary drilling system. Therefore, it is recommended to consider the results of this study in order to design and implement a robust control system to mitigate harmful vibrations; the practical implementation of this model can be advantageous in designing a smart rotary drilling system.Originality/valueMany rock-bit functions have been proposed in the literature, but no study has been dedicated to compare them; this is the main contribution of this study. Moreover, a case study of harmonic torsional vibrations analysis has been carried out in well-A, which is located in an Algerian hydrocarbons field, the indices of vibrations detection are given with their preventions.

Millennial Green Drilling: Deliver More with Less (Solution to the Drilling Operations)

2021 ◽  
Author(s):  
D. Kusumawardhani
Keyword(s):  
Oil And Gas ◽  
Rapid Change ◽  
Virus Transmission ◽  
Oil And Gas Industry ◽  
Stick Slip ◽  
Gas Industry ◽  
Digital Ecosystem ◽  
Drilling Operations ◽  
People Movement ◽  
The Impact

The impact of the COVID-19 pandemic spread across the oil and gas industry, which required a rapid change on the way we deliver drilling activity and avoid operational disruption. To assure continuous offshore Jackup drilling operations, an Operator in East Java area and Schlumberger decided to implement Performance Live digitally connected service. It reduces the risk of virus transmission as well as substitutes the requirement for logistic and related costs for personnel onboard. The multiskilled and multistage of one crew came in conjunction with a digital ecosystem to deliver safer and higher-performing operations with less personnel onboard, resulting in carbon footprint reduction. This initiative reduced the operator Operations wellsite crew size and enabled performing most analytical tasks from the office environment. Using this approach, the operation was successfully conducted with zero HSE or service quality incidents. In addition to the ability to proceed with the operations, rig crew size was reduced by 33% from standard configuration, which lowered carbon print by the same amount. Background and Challenges: The objective of the drilling campaign was to increase oil production in operator’s concession operating block from the carbonate reservoirs by drilling an exploration well in 2020. Known as one of the toughest areas in Indonesia for drilling conditions, this basin has a high possibility of total losses environment and massive thick limestone that posed high stick/slip and shock and vibration. Moreover, the COVID-19 pandemic crisis added unprecedented uncertainty and posed many challenges for the operator ensuring business continuity and drilling operations, especially with regards to health, safety, and operational considerations where operations would be conducted with tough logistics and people movement.

scholarly journals Quantum Dynamics in Continuum for Proton Transport I: Basic Formulation

2013 ◽  
Vol 13 (1) ◽  
pp. 285-324 ◽  
Author(s):  
Duan Chen ◽  
Guo-Wei Wei
Keyword(s):  
Proton Transport ◽  
Quantum Dynamics ◽  
Density Functional ◽  
Molecular Surface ◽  
Electrostatic Energy ◽  
Model Parameters ◽  
Proposed Model ◽  
Wide Range ◽  
Mathematical Algorithms ◽  
The Impact

AbstractProton transport is one of the most important and interesting phenomena in living cells. The present work proposes a multiscale/multiphysics model for the understanding of the molecular mechanism of proton transport in transmembrane proteins. We describe proton dynamics quantum mechanically via a density functional approach while implicitly model other solvent ions as a dielectric continuum to reduce the number of degrees of freedom. The densities of all other ions in the solvent are assumed to obey the Boltzmann distribution. The impact of protein molecular structure and its charge polarization on the proton transport is considered explicitly at the atomic level. We formulate a total free energy functional to put proton kinetic and potential energies as well as electrostatic energy of all ions on an equal footing. The variational principle is employed to derive nonlinear governing equations for the proton transport system. Generalized Poisson-Boltzmann equation and Kohn-Sham equation are obtained from the variational framework. Theoretical formulations for the proton density and proton conductance are constructed based on fundamental principles. The molecular surface of the channel protein is utilized to split the discrete protein domain and the continuum solvent domain, and facilitate the multiscale discrete/continuum/quantum descriptions. A number of mathematical algorithms, including the Dirichlet to Neumann mapping, matched interface and boundary method, Gummel iteration, and Krylov space techniques are utilized to implement the proposed model in a computationally efficient manner. The Gramicidin A (GA) channel is used to demonstrate the performance of the proposed proton transport model and validate the efficiency of proposed mathematical algorithms. The electrostatic characteristics of the GA channel is analyzed with a wide range of model parameters. The proton conductances are studied over a number of applied voltages and reference concentrations. A comparison with experimental data verifies the present model predictions and validates the proposed model.

THE IMPACT OF LEADERSHIP PRACTICES TO TEAM MEMBERS’ SATISFACTION

2009 ◽  
Vol 8 (1) ◽  
Author(s):  
Chalimah .
Keyword(s):  
Conflict Resolution ◽  
Leadership Practices ◽  
Hotel Industry ◽  
Leader Behavior ◽  
Team Leader ◽  
Shop Floor ◽  
Team Members ◽  
Top Executives ◽  
Wide Range ◽  
The Impact

eamwork is becoming increasingly important to wide range of operations. It applies to all levels of the company. It is just as important for top executives as it is to middle management, supervisors and shop floor workers. Poor teamwork at any level or between levels can seriously damage organizational effectiveness. The focus of this paper was therefore to examine whether leadership practices consist of team leader behavior, conflict resolution style and openness in communication significantly influenced the team member’s satisfaction in hotel industry. Result indicates that team leader behavior and the conflict resolution style significantly influenced team member satisfaction. It was surprising that openness in communication did not affect significantly to the team members’ satisfaction.

Stress, anxiety, depression and burnout in frontline health care workers during COVID-19 pandemic: a brief systematic review and new data from Russia

2021 ◽  
Author(s):  
Ekaterina Mosolova ◽  
Dmitry Sosin ◽  
Sergey Mosolov
Keyword(s):  
Risk Factors ◽  
Systematic Review ◽  
Female Gender ◽  
Assessment Tools ◽  
Care Workers ◽  
Younger Age ◽  
Wide Range ◽  
Associated Risk Factors ◽  
Anxiety Depression ◽  
The Impact

During the COVID-19 pandemic, healthcare workers (HCWs) have been subject to increased workload while also exposed to many psychosocial stressors. In a systematic review we analyze the impact that the pandemic has had on HCWs mental state and associated risk factors. Most studies reported high levels of depression and anxiety among HCWs worldwide, however, due to a wide range of assessment tools, cut-off scores, and number of frontline participants in the studies, results were difficult to compare. Our study is based on two online surveys of 2195 HCWs from different regions of Russia during spring and autumn epidemic outbreaks revealed the rates of anxiety, stress, depression, emotional exhaustion and depersonalization and perceived stress as 32.3%, 31.1%, 45.5%, 74.2%, 37.7% ,67.8%, respectively. Moreover, 2.4% of HCWs reported suicidal thoughts. The most common risk factors include: female gender, nurse as an occupation, younger age, working for over 6 months, chronic diseases, smoking, high working demands, lack of personal protective equipment, low salary, lack of social support, isolation from families, the fear of relatives getting infected. These results demonstrate the need for urgent supportive programs for HCWs fighting COVID-19 that fall into higher risk factors groups.

A MODELING SYSTEM FOR CLIMATE CHANGE RISK ASSESSMENT, MANAGEMENT AND HEDGING IN COASTAL AREAS

2017 ◽  
Author(s):  
Sergei Soldatenko ◽  
Sergei Soldatenko ◽  
Genrikh Alekseev ◽  
Genrikh Alekseev ◽  
Alexander Danilov ◽  
...  
Keyword(s):  
Climate Change ◽  
Risk Assessment ◽  
Coastal Areas ◽  
Mitigation Strategies ◽  
System Structure ◽  
The Arctic ◽  
Risk Modeling ◽  
Wide Range ◽  
Adverse Weather ◽  
The Impact

Every aspect of human operations faces a wide range of risks, some of which can cause serious consequences. By the start of 21st century, mankind has recognized a new class of risks posed by climate change. It is obvious, that the global climate is changing, and will continue to change, in ways that affect the planning and day to day operations of businesses, government agencies and other organizations and institutions. The manifestations of climate change include but not limited to rising sea levels, increasing temperature, flooding, melting polar sea ice, adverse weather events (e.g. heatwaves, drought, and storms) and a rise in related problems (e.g. health and environmental). Assessing and managing climate risks represent one of the most challenging issues of today and for the future. The purpose of the risk modeling system discussed in this paper is to provide a framework and methodology to quantify risks caused by climate change, to facilitate estimates of the impact of climate change on various spheres of human activities and to compare eventual adaptation and risk mitigation strategies. The system integrates both physical climate system and economic models together with knowledge-based subsystem, which can help support proactive risk management. System structure and its main components are considered. Special attention is paid to climate risk assessment, management and hedging in the Arctic coastal areas.

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