Dynamic Modeling of Bottomhole Assembly

2014 ◽  
Author(s):  
Madhu Vadali ◽  
Zhijie Sun ◽  
Yuzhen Xue ◽  
Jason Dykstra
Keyword(s):  
Dynamic Model ◽  
Oil And Gas ◽  
System Development ◽  
Beam Theory ◽  
Flexible Beam ◽  
Fluid Mud ◽  
Directional Drilling ◽  
Lumped Mass ◽  
Stick Slip ◽  
Drilling System

This paper presents a comprehensive 4D dynamic model of a bottomhole assembly (BHA) used for directional drilling of oil and gas wells. Although directional drilling has been in practice for some time, it still poses several challenges, particularly related to building an autonomous drilling system. The difficulty with drilling automation derives from the complexity of the process that includes interaction with the borehole and fluid (mud) flow and complex downhole vibrations, such as bit-bounce (axial), whirl (lateral), and stick/slip (torsional). Moreover, the measurements from a limited number of downhole sensors are usually contaminated with high noise levels, and can only be transmitted at low rates with long transmission delays using mud pulsing, or at a high cost using wired pipe. Therefore, it is preferable that the directional drilling system work autonomously with limited communication to the surface. To facilitate this, a compressive physics-based model of the BHA behavior was created to be used in control system development. In this work, the 4D dynamic model of the BHA accounts for the dynamics in rotation, axial motion, and bending along two lateral directions. The model uses a lumped mass-spring system and the system parameters (mass and stiffness) are derived from the shear beam theory of a flexible beam under certain boundary conditions. Simulation results of the model were successful in qualitatively replicating the three types of downhole vibrations, namely bit-bounce, whirl, and stick/slip, and are discussed in this paper. The model is shown to qualitatively replicate downhole conditions and can be implemented in real-time, thereby making it suitable for autonomous directional drilling control.

Training an Automated Directional Drilling Agent with Deep Reinforcement Learning in a Simulated Environment

2021 ◽  
Author(s):  
Yingwei Yu ◽  
Wei Chen ◽  
Qiuhua Liu ◽  
Minh Chau ◽  
Velizar Vesselinov ◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
Oil And Gas ◽  
Cost Effective ◽  
Oil And Gas Industry ◽  
High Volume ◽  
Optimal Operation ◽  
Earth Model ◽  
Directional Drilling ◽  
Simulated Environment ◽  
Drilling System

Abstract Drilling a directional well becomes an essential process in the oil and gas industry to ensure better reservoir exposure and less wellbore collision risk. In the high-volume drilling market, cost-effective mud motors are dominant. The motor is capable of delivering the desired well curvature by switching between rotating and sliding operations. Therefore, to follow a predefined well trajectory, it is a critical mission to determine the optimal operation control sequence of the motor. In this paper, a method of training an automatic agent for motor directional drilling using the deep reinforcement learning approach is proposed. In designing the method, motor-based directional drilling is framed into the reinforcement learning with an automatic drilling system, also known as an agent, interacting with an environment (i.e., formations, wellbore geometry, equipment) through choices of controls in a sequence. The agent perceives the states such as inclination, MD, TVD at survey points and the planned trajectories from the environment, and then decides the best action of sliding or rotating to achieve the maximum total rewards. The environment is affected by the agent's actions and returns corresponding rewards to the agent. The rewards can be positive (such as drilling to target) or negative (such as offset distance to the planned trajectory, cost of drilling, and action switching). To train our agent, currently, a drilling simulator in a simulated environment is created with layered earth model and BHA directional responses in layers. Other attributes of the drilling system are assumed to be constant and handled automatically by the simulator. The planned trajectory is also provided to the agent while training. The directional-drilling agent is trained for thousands of episodes. As a result, the agent can successfully drill to target in this simulated environment through the decisions of sliding and rotating. The proposed workflow is known as the first automated directional drilling method based on deep reinforcement learning, which makes a sequence of decisions of rotating and sliding actions to follow a planned trajectory.

scholarly journals Dynamic Model of a Rotating Flexible Arm-Flexible Root Mechanism Driven by a Shaft Flexible in Torsion

2006 ◽  
Vol 13 (6) ◽  
pp. 577-593 ◽  
Author(s):  
S.Z. Ismail ◽  
A.A. Al-Qaisia ◽  
B.O. Al-Bedoor
Keyword(s):  
Dynamic Model ◽  
Equations Of Motion ◽  
Beam Theory ◽  
Small Deformation ◽  
Coupled System ◽  
Practical Implementation ◽  
Flexible Beam ◽  
Nonlinear Coupled System ◽  
Linearized System ◽  
Euler Bernoulli Beam

This paper presents a dynamic model of a rotating flexible beam carrying a payload at its tip. The model accounts for the driving shaft and the arm root flexibilities. The finite element method and the Lagrangian dynamics are used in deriving the equations of motion with the small deformation theory assumptions and the Euler-Bernoulli beam theory. The obtained model is a nonlinear-coupled system of differential equations. The model is simulated for different combinations of shaft and root flexibilities and arm properties. The simulation results showed that the root flexibility is an important factor that should be considered in association with the arm and shaft flexibilities, as its dynamics influence the motor motion. Moreover, the effect of system non-linearity on the dynamic behavior is investigated by simulating the equivalent linearized system and it was found to be an important factor that should be considered, particularly when designing a control strategy for practical implementation.

scholarly journals A Dynamic Model for Continuous Lowering Analysis of Deep-Sea Equipment, Based on the Lumped-Mass Method

2020 ◽  
Vol 10 (9) ◽  
pp. 3177
Author(s):  
Pan Gao ◽  
Keliang Yan ◽  
Mingchen Ni ◽  
Xuehua Fu ◽  
Zhihui Liu
Keyword(s):  
Dynamic Model ◽  
Oil And Gas ◽  
System Response ◽  
Dynamic Force ◽  
Structural Damping ◽  
Lumped Mass ◽  
Nonlinear Loads ◽  
Oil And Gas Development ◽  
Lumped Mass Method ◽  
Heave Motion

The installation of subsea equipment is a critical step in offshore oil and gas development. A dynamic model to evaluate the lowering process is proposed. The cable–payload system is discretized as a series of spring dampers with the lumped-mass method. For the first time, not only the lowering velocity but also the rope’s structural damping and the nonlinear loads, such as drag force and snap load, are considered. The lowering velocity of the cable is considered through a variable-domain technique. Snap loads are considered by setting the internal forces in the elements to be zero when the cable slacks. A series of simulations reveals that the lowering velocity has great effects on the dynamic force in the cable. However, the structural damping of the cable has little effect on the system response. The snap load may occur in the cable when subjected to rapid downward heave motion, and decreases with the lowered depth increasing. The cable stiffness affects the system’s resonance depth, but has little effect on the peak dynamic force. The present work should be a valuable reference for future subsea equipment installation analysis.

Technology Focus: Bits and Bottomhole Assemblies (December 2020)

2020 ◽  
Vol 72 (12) ◽  
pp. 52-52
Author(s):  
Graham Mensa-Wilmot
Keyword(s):  
High Frequency ◽  
System Analysis ◽  
Vibration Modes ◽  
Directional Drilling ◽  
Stick Slip ◽  
Drilling Performance ◽  
Downhole Tool ◽  
Drilling Parameter ◽  
Drilling System ◽  
Project Objectives

Achieving and sustaining performance drilling’s intended benefits - improved drilling efficiency with minimal down-hole tool failures and the associated reductions in project cycle time and operational costs - requires new protocols in drilling-system analysis. Drilling-system components [bits, reamers, bottomhole assemblies (BHAs), drive systems, drilling parameters, and hydraulics] must be analyzed independently for their relevance on the basis of application types and project challenges. Additionally, the drilling system must undergo holistic evaluations to establish functional compatibility and drilling-parameter responses and effects, considering project objectives and key performance indicators. This comprehensive physics-based approach ensures durability and rate-of-penetration (ROP) improvements without compromising stability and downhole tool reliability. The success of this process is strongly dependent on vibration control. Considering the different vibration modes - axial, torsional, lateral, stick/slip, and whirl - and their many dissimilar initiating and amplification factors, their sources always must be identified. Researchers have challenged the usual classification of erratic torque and revolution-rate behavior as stick/slip. BHA design and drilling-parameter ranges, considering blade spacing, can produce unfavorable tubular deformations, contact points, and side loads. This condition creates torque and revolution-rate fluctuations that have been linked to lateral vibrations. Awareness of these vibration modes, particularly their sources and intensifying conditions, ensures development of effective remediation solutions. Improved borehole quality, with regard to tortuosity and rugosity, must always be considered as a critical requirement in performance drilling. This condition reduces borehole drag, enhances drilling-parameter transfer, and improves ROP and overall run lengths. Most importantly, it reduces vibrations, leading to improvements in downhole tool life and directional drilling performance. In addition to formation drillability effects, drilling-systems components and operational practices have strong effects on borehole quality. Consequently, this must be part of the drilling-system analysis. The industry’s advancements at developing physics-based solutions for drilling challenges have matured. Continuing to ask questions that help us understand how and why we fail or succeed puts more wind beneath our wings to accelerate learning and reduce cycle times. Recommended additional reading at OnePetro: www.onepetro.org. SPE 200740 Digital Twins for Well Planning and Bit-Dull-Grade Prediction by Mehrdad Gharib Shirangi, Baker Hughes, et al. SPE 201616 Validating Bottomhole-Assembly Analysis Models With Real-Time Measurements for Improved Drilling Performance by Mark Smith, Premier Directional Drilling, et al. IADC/SPE 199658 Simulation and Measurement of High-Frequency Torsional Oscillation (HFTO)/High-Frequency Axial Oscillation and Downhole HFTO Mitigation: Knowledge Gains Continue by Using Embedded High-Frequency Drilling Dynamics Sensors by Junichi Sugiura, Sanvean Technologies, et al.

scholarly journals Optimization of Drillstring Design to Produce More Stable Dynamic Drilling on Horizontal Drilling by Applying Different Stiffness Combinations

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Dundie Prasetyo ◽  
Ratnayu Sitaresmi ◽  
Suryo Prakoso
Keyword(s):  
Data Acquisition ◽  
Oil And Gas ◽  
Drill Pipe ◽  
Drill String ◽  
Drilling Process ◽  
Directional Drilling ◽  
Horizontal Section ◽  
Stick Slip ◽  
Horizontal Drilling ◽  
Drilling Operation

<p>Horizontal drilling technique is one of the methodologies that have been widely implemented recently to improve the production of oil and gas wells. Several directional drilling technologies can be utilized to drill the horizontal wells, vary from the simple mud motor technology to Bottom Hole Assembly (BHA) with the advanced motorized rotary steerable system. The most common challenges that are faced on horizontal drilling process are on the torque and the stick-slip throughout drilling process, which can be a technical limiter for the length of horizontal section that would be achieved. Stick-slip is the vibration <br />that occurs due to cyclical rotation acceleration and deceleration of the bit, BHA or drill string. This speed fluctuation can be zero to rate of penetration (ROP) or far in excess of twice the rotational speed measured at the surface. Stick-slip can significantly decrease the ROP, increases tool failures and damage, affects borehole quality, and impacts the data acquisition. Several studies had been done on the stick-slip prevention and mitigation throughout creation of new technology and drilling parameters envelope throughout drilling operation, however no study has ever been done on the modification of the design and <br />arrangement of the BHA itself to produce more stable BHA. Drill pipe is the longest component of the drill string and hence it has biggest contribution towards the drill string dynamic. This study will focus on the analysis of the combination of several designs of the drill-pipe and heavy weight drill-pipe (HWDP) that has different stiffness and characteristic to produce less <br />vibration, more efficient drilling operation and to create zero impact on the data acquisition measured while drilling. FEA drilling dynamic simulator was used to optimize the drill sting configuration. The calculation is made from the depth of 750 m to 2801 m. Based on the drilling simulation results of FEA modeling, it is concluded that the minimum stiffness ratio to give stability of the drill string of Well-Z7 BHA and Well-Z6 BHA is 0.012175272 and 0.07366999, respectively.</p>

Robotic Controlled Drilling: A New Rotary Steerable Drilling System for the Oil and Gas Industry

2002 ◽  
Author(s):  
Yonezawa Tetsuo ◽  
Edward J. Cargill ◽  
Tom M. Gaynor ◽  
J.R. Hardin ◽  
Richard T. Hay ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Gas Industry ◽  
Drilling System

scholarly journals The Study of Dynamic Modeling and Multivariable Feedback Control for Flexible Manipulators with Friction Effect and Terminal Load

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1522
Author(s):  
Fuli Zhang ◽  
Zhaohui Yuan
Keyword(s):  
Dynamic Model ◽  
Vibration Suppression ◽  
Control Method ◽  
Coupling Effect ◽  
Flexible Manipulator ◽  
Flexible Beam ◽  
Robot Dynamics ◽  
Joint Friction ◽  
Balance Principle ◽  
Multivariable Feedback

The flexible manipulato is widely used in the aerospace industry and various other special fields. Control accuracy is affected by the flexibility, joint friction, and terminal load. Therefore, this paper establishes a robot dynamics model under the coupling effect of flexibility, friction, and terminal load, and analyzes and studies its control. First of all, taking the structure of the central rigid body, the flexible beam, and load as the research object, the dynamic model of a flexible manipulator with terminal load is established by using the hypothesis mode and the Lagrange method. Based on the balance principle of the force and moment, the friction under the influence of flexibility and load is recalculated, and the dynamic model of the manipulator is further improved. Secondly, the coupled dynamic system is decomposed and the controller is designed by the multivariable feedback controller. Finally, using MATLAB as the simulation platform, the feasibility of dynamic simulation is verified through simulation comparison. The results show that the vibration amplitude can be reduced with the increase of friction coefficient. As the load increases, the vibration can increase further. The trajectory tracking and vibration suppression of the manipulator are effective under the control method of multi-feedback moment calculation. The research is of great significance to the control of flexible robots under the influence of multiple factors.

Learnings from Building a Vendor Agnostic Automated Directional Drilling System

2021 ◽  
Author(s):  
Titto Thomas Philip ◽  
Sergey Ziatdinov
Keyword(s):  
Business Performance ◽  
Low Cost ◽  
Directional Drilling ◽  
Paradigm Shifts ◽  
Process Data ◽  
Vast Number ◽  
Automation Systems ◽  
Bottom Hole Assembly ◽  
Drilling System ◽  
Roll Out

Abstract The post COVID-19 era will undoubtedly present paradigm shifts in operational planning and execution and advanced automation will become an important factor. However, drilling automation without directional drilling (Cayeux 2020) capability will exclude the use of automation in a vast number of fields where precise placement of the wellbore has shifted from a luxury to a necessity. This is important in unconventional plays where automation can make a step change in operational outcomes (Chmela 2020). However, most efforts in automating directional drilling are using bespoke rigs (Slagmulder 2016) and bespoke bottom hole assembly (BHA) that limit operational options. The goal is in designing systems that enable directional drilling automation (Chatar 2018) with existing BHAs. This paper will look at three challenges that were identified and overcome to deploy a vendor agnostic system for automating the directional drilling (DD) process. The three challenges identified here are as follows:Using any mud motor including low-cost motors in a closed loopIntegration with an existing measurement and logging while drilling (MLWD) systemAbility to roll out automation systems on any operations with existing rigs The system is a modification of an operator’s autonomous drilling system (Rassenfoss 2011), designed to use existing rigs, BHAs and have minimum footprint on the rigs for operational use. The system will have a dedicated connection to the rig’s programmable logic controller (PLC) via common industrial protocols including Modbus, EthernetIP or Profinet, a physical connection the MLWD receiver and a brain box with a cloud connection to aggregate, process data and send commands to the rig PLC to execute directional commands. A vendor agnostic system will increase adoption of automated technologies and further drive improvements in operational and business performance.

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