Modelling of the Dynamic Behavior of the Power Transmission of an Automatic Small Scale Drilling Rig

2017 ◽  
Author(s):  
Eric Cayeux ◽  
Hans Joakim Skadsem
Keyword(s):  
Mathematical Models ◽  
Physical System ◽  
Power Transmission ◽  
Drill String ◽  
Laboratory Scale ◽  
Small Scale ◽  
Drilling Process ◽  
Drilling Rig ◽  
Contact Points ◽  
Drilling Conditions

The automatization of the drilling process opens the opportunity to faster reactions in case of unexpected drilling conditions, therefore reducing the risk that a drilling incident escalates to a serious situation. It also allows to push the drilling performance to be as close as possible to the limits of drillability as a function of the varying drilling conditions. But to achieve high level of drilling process automation, it is necessary to have access to accurate mathematical models of the complex physical system that is composed of the drilling rig, the drill-string, the drilling fluid and the borehole itself. As the development of accurate heat transfer, mechanical and hydraulic models and their utilization in full scale drilling applications is a huge and complex task, it is tempting to recreate drilling automatization problems in a laboratory scale setup. Because of sudden variations of the downhole drilling conditions, like when transitioning from soft to hard rock or when the bit is subject to large torque variations induced by interbedded rock layers, the boundary conditions at the bit change suddenly and require quick response from the automatic top-drive and hoisting system controllers. At a small laboratory scale, the necessary reaction times are of the order of milliseconds and therefore exclude any manual intervention. It is therefore crucial that the automatic control methods utilize precise mathematical models of the physical system to accurately estimate the limits by which the drilling process can be managed under safe conditions. For that reason, a general purpose mathematical model of small-scale drilling rigs has been developed. First, the Rayleigh-Ritz method is used to determine the deflection of the drill-string and to estimate the side forces at the contact points along the drill-string and BHA (Bottom Hole Assembly). Then the dynamic response of the power transmission system is modelled for both variable frequency drive controlled tri-phase motors and for stepper motors, including friction effects at the contact points. Friction is modelled using Stribeck theory rather than the classical Coulomb laws of friction. Finally, the expected response of 3D accelerometers, that could be placed on the outside of a BHA component, is modelled to retrieve possible inclination variations and potential vibration modes such as torsional oscillations, forward or backward whirl. The generality of the model is such that it can be used for many small-scale drilling rig designs.

scholarly journals Small-Scale Drilling Test Rig For Investigation of Axial Excitation On The Drilling Process

2018 ◽  
Vol 148 ◽  
pp. 16001
Author(s):  
A. Austefjord ◽  
S. Blaylock ◽  
I. Forster ◽  
M. Sheehan ◽  
C. Wright
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Low Frequency ◽  
Advanced Technology ◽  
Small Scale ◽  
Drilling Process ◽  
Generation Process ◽  
Rock System ◽  
Drilling Rig ◽  
Axial Excitation

This paper describes the design, construction and operation of a small-scale drilling rig for the purpose of investigation of the effect of axial excitation on the drilling process. The rig is bench top in size and has been designed to drill small rock samples, whilst at the same allowing axial excitation to be induced into the drilling process. The rig has been designed to drill the rock without any drilling fluids – so allowing improved observation of the chip generation process. Additionally, the drilling weight on bit is applied via masses, so allowing greater representation of the dynamic behavior of the drilling process – i.e. capturing more natural frequencies. The results from the rig have been obtained over two frequency ranges – low frequency (0-50 Hz) and high frequency (50-250 Hz). Results show that improved rate of penetration is obtained with axial excitation – with low and high frequency optima occurring. These optima can be related to the behavior of the string in the two frequency ranges – in the low frequency range, the entire string acts in unison; whereas at high frequency, only the bit/rock system is active. As a result, it is concluded that for low frequency operation, only information about the drill string is required to optimize performance; whereas for high frequency operation, information about the bit/rock system is required to optimize performance. Observation of the chip generation process via high speed video has shown that during axial excitation, regular shaped bricks are ejected when compared with the typical wedge- shaped chips that are normally ejected during the drilling process. It is concluded that, during the axial excitation process, the chips are being ejected via a levering action, so allowing a more efficient and quicker process. MIT [1] provided background classes, project guidance and project review as part of an NOV/MIT advanced technology program. Larger scale lab tests and/or field tests are required to verify/validate these conclusions.

Directional Drilling Automation Using a Laboratory-Scale Drilling Rig: SPE University Competition

2020 ◽  
pp. 1-10
Author(s):  
Emmanuel Akita ◽  
Forrest Dyer ◽  
Savanna Drummond ◽  
Monica Elkins ◽  
Payton Duggan ◽  
...  
Keyword(s):  
Steering System ◽  
Lessons Learned ◽  
Laboratory Scale ◽  
Small Scale ◽  
Directional Drilling ◽  
Design Development ◽  
Rock Interaction ◽  
Precise Control ◽  
Drilling Rig ◽  
Downhole Sensors

Summary The use of drilling automation is accelerating, mostly in the area of rate of penetration (ROP) enhancement. Autonomous directional drilling is now a high focus area for automating drilling operations. The potential impact is immense because 93% of the active rigs in the US are drilling directional or horizontal wells. The 2018–2019 Drilling Systems Automation Technical Section (DSATS)-led international Drillbotics® Student Competition includes automated directional drilling. In this paper, we discuss the detailed design of the winning team. We present the surface equipment, downhole tools, data and control systems, and lessons learned. SPE DSATS organizes the annual Drillbotics competition for university teams to design and develop laboratory-scale drilling rigs. The competition requires each team to create unique downhole sensors to allow automated navigation to drill a directional hole. Student teams have developed new rig configurations to enable several steering methods that include a rotary steering system and small-scale downhole motors with a bent-sub. The most significant challenge was creating a functional downhole motor to fit within a 1.25-in. (3.18 cm) diameter wellbore. Besides technical issues, teams must demonstrate what they have learned about bit-rock interaction and the physics of steering. In addition, they must deal with budgets and funding, procurement and delivery delays, and overall project management. This required an integrated multidisciplinary approach and a major redesign of the rig components. The University of Oklahoma (OU) team made significant changes to its existing rig to drill directional holes. The design change was introduced to optimize the performance of the bottomhole assembly (BHA) and allow directional drilling. The criteria for selecting the BHA was hole size, BHA dynamics, a favorable condition for downhole sensors, precise control of drilling parameters, rig mobility, safety, time constraints, and economic practicality. The result is an autonomous drilling rig that drills a deviated hole toward a defined target through a 2 × 2 × 1-ft (60.96 × 60.96 × 30.48 cm) sandstone block (i.e., rock sample) without human intervention. The rig currently uses a combination of discrete and dynamic modeling from experimentally determined control parameters and closed-loop feedback for well-trajectorycontrol. The novelty of our winning design is in the use of a small-scale cable-driven downhole motor with a bent-sub and quick-connect-type swivel system. This is intended to replicate the action of a mud motor within the limits of the borehole diameter. In this paper, we present details of the rig components, their specifications, and the problems faced during the design, development, and testing. We demonstrate how a laboratory-scale rig can be used to study drilling dysfunctions and challenges. Building a downhole tool to withstand vibrations, water intrusion, magnetic interference, and electromagnetic noise are common difficulties faced by major equipment manufacturers.

scholarly journals Drilling cores on the sea floor with the remote-controlled sea-floor drilling rig MeBo

2013 ◽  
Vol 3 (2) ◽  
pp. 347-369 ◽  
Author(s):  
T. Freudenthal ◽  
G. Wefer
Keyword(s):  
Deep Sea ◽  
Mineral Resources ◽  
Drill String ◽  
Drilling Process ◽  
Sea Floor ◽  
Climate Fluctuations ◽  
Drilling Rig ◽  
Offshore Installations ◽  
Recovery System ◽  
Marine Environmental

Abstract. Sampling of the upper 50 to 200 m of the sea floor to address questions relating to marine mineral resources and gas hydrates, for geotechnical research in areas of planned offshore installations, to study slope stability, and to investigate past climate fluctuations, to name just a few examples, is becoming increasingly important both in shallow waters and in the deep sea. As a rule, the use of drilling ships for this kind of drilling is inefficient because before the first core can be taken a drill string has to be assembled extending from the ship to the sea floor. Furthermore, movement of the ship due to wave motion disturbs the drilling process and often results in poor core quality, especially in the upper layers of the sea floor. For these reasons, the MeBo drilling rig, which is lowered to the sea floor and operated remotely from the ship to drill up to 80 m into the sea floor, was developed at the MARUM Research Center for Marine Environmental Sciences at Bremen University. The complete system, comprising the drill rig, winch, control station, and the launch and recovery system, is transported in six containers and can be deployed worldwide from German and international research ships. It was the first remote-controlled deep sea drill rig that uses a wireline coring technique. Based on the experiences with the MeBo a rig is now being built that will be able to drill to a depth of 200 m.

scholarly journals Drilling cores on the sea floor with the remote-controlled sea floor drilling rig MeBo

2013 ◽  
Vol 2 (2) ◽  
pp. 329-337 ◽  
Author(s):  
T. Freudenthal ◽  
G. Wefer
Keyword(s):  
Complete System ◽  
Drill String ◽  
Drilling Process ◽  
Stability Studies ◽  
Sea Floor ◽  
Drilling Rig ◽  
Research Fields ◽  
Sea Bed ◽  
Recovery System ◽  
Marine Environmental

Abstract. The sea floor drill rig MeBo (acronym for Meeresboden-Bohrgerät, German for sea floor drill rig) is a robotic drill rig that is deployed on the sea floor and operated remotely from the research vessel to drill up to 80 m into the sea floor. It was developed at the MARUM Research Center for Marine Environmental Sciences at Bremen University. The complete system – comprising the drill rig, winch, control station, and the launch and recovery system – is transported in six containers and can be deployed worldwide from German and international research ships. It was the first remote-controlled deep sea drill rig to use a wireline coring technique. Compared to drilling vessels this technology has the advantage of operating from a stable platform at the sea bed, which allows for optimal control over the drilling process. Especially for shallow drillings in the range of tens to hundreds of metres, sea bed drill rigs are time-efficient since no drill string has to be assembled from the ship to the sea floor before the first core can be taken. The MeBo has been successfully operated, retrieving high-quality cores at the sea bed for a variety of research fields, including slope stability studies and palaeoclimate reconstructions. Based on experience with the MeBo, a rig is now being built that will be able to drill to a depth of 200 m.

scholarly journals VIBRATIONS AND STABILITY OF A GEOMETRICALLY NONLINEAR WEIGHTY DRILL STRING FOR DRILLING OIL AND GAS WELLS

2021 ◽  
Vol 2 (446) ◽  
pp. 6-14
Author(s):  
S. М. Akhmetov ◽  
M. Diarov ◽  
N. М. Akhmetov ◽  
D. T. Bizhanov ◽  
Zh. K. Zaidemova
Keyword(s):  
Oil And Gas ◽  
Drill Pipe ◽  
Nonlinear Problems ◽  
Physical Nonlinearity ◽  
Drill String ◽  
Contact Forces ◽  
Drilling Process ◽  
Geometrically Nonlinear ◽  
Drilling Rig ◽  
Drilling System

Heavy weight drill pipe (HWDP) in wells are hollow, weighty rods with stepwise changing physical properties (for example, stiffness), and each link of the string can deform according to geometrically nonlinear laws. They are the most critical part in the drilling process, transmitting power from the drilling rig to the rock failing tool, and are in hydrodynamic and contact interaction with the borehole walls, and are always curved. This occurs due to the curvature of the well itself, and under the action of its own weight, contact forces, as well as centrifugal forces in the case of rotation of the pipe. In this case, the curvature of the HWDP axis can be significantly influenced by the geometric nonlinearity of the deformation of its pipes. A review of this issue revealed a number of poorly studied problems, which include accounting for both phy- sically and geometrically nonlinear problems, accompanied by various types of complications (loss of stability HDWP, pipe breaks, etc.), as well as other processes in the elements of a dynamic drilling system (DDS). In this paper, based on the use of modern methods for studying dynamic processes in mechanical systems, a method is proposed for studying longitudinal oscillations of a geometrically nonlinear HWDP of its stability under torsion, taking into account the physical nonlinearity in the process of its deformation. The dependences characte- rizing this process are found.

Electromagnetically excited torsional vibration to rock drilling support

2020 ◽  
pp. 1-14
Author(s):  
Tomasz Trawiński ◽  
Marcin Szczygieł ◽  
Arkadiusz Tomas
Keyword(s):  
Mathematical Models ◽  
Torsional Vibration ◽  
Drilling Process ◽  
Torsional Vibrations ◽  
Research Fund ◽  
Incident Response ◽  
European Research ◽  
Rescue Operation ◽  
Drilling Rig ◽  
Drilling System

During a serious underground incident the most important things are the lives of miners and the time necessary for the rescue team to find victims of the accident. The paper presents the concept of a new drilling system that uses torsional vibrations in the drilling process. In the article formulating mathematical models of a drilling rig is one of the tasks of the INDIRES (INformation Driven Incident RESponse) project implemented as a part of the European Research Fund for Coal and Steel. The INDIRES project is dedicated to the task of conducting a rescue operation after accidents in mines.

Similarity Analysis for Downscaling a Full Size Drill String to a Laboratory Scale Test Drilling Rig

2018 ◽  
Author(s):  
Adrian Ambrus ◽  
Hans Joakim Skadsem ◽  
Rodica G. Mihai
Keyword(s):  
Large Scale ◽  
Scaling Laws ◽  
Oil And Gas ◽  
Drill String ◽  
Similarity Criteria ◽  
Laboratory Model ◽  
Similarity Analysis ◽  
Drilling Process ◽  
Drilling Rig ◽  
Laboratory Conditions

The drill string used in drilling oil and gas wells is a long and slender structure that is confined by the wellbore wall and subject to significant axial, lateral and torsional vibrations while drilling. Detection and mitigation of drill string vibrations are especially important, as vibrations can be hard to detect at the surface, yet cause significant damage to the drill bit, downhole tools and the formation being drilled. Study of the drilling process by downscaling to laboratory conditions is an attractive prospect as it is a cost-efficient alternative to dedicated large-scale testing and it can be instrumented to provide vibration measurements from different locations along the string. However, the extreme geometrical length scales, the complex wellbore trajectories and the large mechanical strains on the drill string lead to challenges when attempting to downscale the drilling process to manageable laboratory conditions. Downscaling based on similarity analysis provides consistent scaling laws for predicting large-scale dynamics based on observations from the downscaled test drilling rig. We perform a similarity analysis for an example full scale drill string that illustrates these challenges in terms of similarity criteria for an equivalent laboratory model of the drill string. We focus particularly on the geometric and mechanical properties of the drill string and consequences of downscaling on the time scale and the forces in the string. We illustrate the downscaling criteria through numerical simulations by solving the governing equations of motion at different scales, and provide recommendations for downscaling based on widely available material types.

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.

scholarly journals Autonomous Decision-Making While Drilling

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 969
Author(s):  
Eric Cayeux ◽  
Benoît Daireaux ◽  
Adrian Ambrus ◽  
Rodica Mihai ◽  
Liv Carlsen
Keyword(s):  
Decision Making ◽  
Internal State ◽  
Drilling Process ◽  
Autonomous Decision ◽  
Internal States ◽  
Markov Decision ◽  
Drilling Operations ◽  
Drilling System ◽  
Drilling Conditions ◽  
Erratic Behavior

The drilling process is complex because unexpected situations may occur at any time. Furthermore, the drilling system is extremely long and slender, therefore prone to vibrations and often being dominated by long transient periods. Adding the fact that measurements are not well distributed along the drilling system, with the majority of real-time measurements only available at the top side and having only access to very sparse data from downhole, the drilling process is poorly observed therefore making it difficult to use standard control methods. Therefore, to achieve completely autonomous drilling operations, it is necessary to utilize a method that is capable of estimating the internal state of the drilling system from parsimonious information while being able to make decisions that will keep the operation safe but effective. A solution enabling autonomous decision-making while drilling has been developed. It relies on an optimization of the time to reach the section total depth (TD). The estimated time to reach the section TD is decomposed into the effective time spent in conducting the drilling operation and the likely time lost to solve unexpected drilling events. This optimization problem is solved by using a Markov decision process method. Several example scenarios have been run in a virtual rig environment to test the validity of the concept. It is found that the system is capable to adapt itself to various drilling conditions, as for example being aggressive when the operation runs smoothly and the estimated uncertainty of the internal states is low, but also more cautious when the downhole drilling conditions deteriorate or when observations tend to indicate more erratic behavior, which is often observed prior to a drilling event.

Study of stick–slip suppression and robustness to parametric uncertainty in drill strings containing torsional vibration tool using sliding-mode control

2021 ◽  
pp. 146441932110452
Author(s):  
Jialin Tian ◽  
Jie Wang ◽  
Siqi Zhou ◽  
Yinglin Yang ◽  
Liming Dai
Keyword(s):  
Torsional Vibration ◽  
Complex Dynamics ◽  
Sliding Mode ◽  
Parametric Uncertainty ◽  
Drill String ◽  
Lumped Parameter Model ◽  
Drilling Process ◽  
Drill Bit ◽  
Stick Slip ◽  
Drilling Operations

Excessive stick–slip vibration of drill strings can cause inefficiency and unsafety of drilling operations. To suppress the stick–slip vibration that occurred during the downhole drilling process, a drill string torsional vibration system considering the torsional vibration tool has been proposed on the basis of the 4-degree of freedom lumped-parameter model. In the design of the model, the tool is approximated by a simple torsional pendulum that brings impact torque to the drill bit. Furthermore, two sliding mode controllers, U1 and U2, are used to suppress stick–slip vibrations while enabling the drill bit to track the desired angular velocity. Aiming at parameter uncertainty and system instability in the drilling operations, a parameter adaptation law is added to the sliding mode controller U2. Finally, the suppression effects of stick–slip and robustness of parametric uncertainty about the two proposed controllers are demonstrated and compared by simulation and field test results. This paper provides a reference for the suppression of stick–slip vibration and the further study of the complex dynamics of the drill string.

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