Development of laboratory and field scale passive vibration assisted rotary drilling tools

The Drilling Technology Laboratory (DTL) at Memorial University of Newfoundland has been focused on increasing drilling efficiency through the utilization of downhole vibrations, also known as Vibration Assisted Rotary Drilling (VARD). The pursuit of VARD technologies is split between active and passive vibrations and the current thesis looks at the design, development, and testing of a Passive Vibration Assisted Rotary Drilling tool (pVARD). The pVARD tool acts as a spring and damper inside the bottom hole assembly of the drill string. It is a system that is tuned to utilize the natural vibrations of the drilling process to increase drilling efficiency and rate of penetration. Two different tools were designed. First, a laboratory scale tool designed to allow analysis into pVARD to be performed on the DTL’s inhouse small drilling simulator. This would allow for rapid testing of many spring damper configurations. The second, a field scale tool, that would be used with six-inch drill bits in the DTL’s first field trial of VARD technology. Powered by a water well drilling rig, this tool would be used to drill shale and granite and explore the pVARD technology on an industrial scale. Both tools required the design of axial and torque taking members as well as the arrangement of the spring damper system. Specific design attention was paid to making the tools easily reconfigurable so that different spring damper arrangements could be tested, both in the lab, and the field. This investigation explores the testing results of these two tools as compared to one another, as well as learning from the operation of them in the field and how these learning will be used to improve the next generation of pVARD tools

Investigation of Bit-Rock Interaction for Rotary Drilling and Influence on Penetration Rate

In this thesis a comprehensive investigation of non-natural vibration on enhanced drilling performance is studied. The Drilling Technology Laboratory (DTL) at Memorial University of Newfoundland has been working on a passive Vibration Assisted Rotational Drilling (p-VARD) tool which helps to increase the drilling rate of penetration (ROP) during laboratory testing and filed work for this couple of years. It has been proven by laboratory experiments and filed work that axial vibration can play a dramatically positive role in improving drilling ROP. Meanwhile, the laboratory measurement and field trial results show that the new passive vibration tool with sensor-sub can provide compatible and accurate data to identify drill string motions including rotatory speed, bit orientation, and bit vibrations including axial, lateral, torsional vibrations and bit whirl. These raw data from each drilling experiment can supply a sufficient research basis for numerical simulation. This thesis focuses on the effect of axial vibration on polycrystalline diamond compact (PDC) bit drilling performance using Discrete Element Method (DEM) simulation and experiments with the new vibration tool. Drill-off tests were conducted in the laboratory with axial vibration on the drill string. Vibration properties were adjusted by different settings of spring compliance and dampening layers. In order to study the cutting performance of the new tool, a PFC2D (Particle Flow Code in 2 Dimensions) numerical model was developed to simulate the micro-crack generation and propagation during the drilling process in synthetic rock samples. This experimental data was used to calibrate this numerical model to real drilling situations. The analyses of the Mechanic Specific Energy (MSE), the Material Removal Rate (MRR) and the Depth of Cut (DOC) are compared with a non-vibration case to evaluate ROP and drilling efficiency. The simulations result demonstrated significant increase in drilling performance when the p-VARD tool was used in the process. Simulation results of the two types of conditions of tools were analyzed and compared in lab and field work experiment respectively. The experimental data agrees with numerical simulation results which indicate it as a promising method to simulate PDC cutter-rock interaction with DEM modelling using the new pVARD tool

Experimental and numerical investigation of drilling performance in anisotropic formations and with axial compliance at the bit

As drilling performance is a key indicator of success in the oil and gas industry, numerous academic and industry organizations have been researching how to improve drilling with regard to time and efficiency. A study is done to determine rock isotropy by applying mechanical and physical measurements, along with oriented drilling, as anisotropy has a distinct impact in drill performance. Based on these findings, the study then performs drilling experiments on anisotropic rock in order to gauge the effect of anisotropy on drill efficiency. The tests employ a dual-cutter PDC bit, 35 mm, and use several different WOB under constant atmospheric pressure and water flow. In looking at relationships of WOB, ROP and DOC, it is clear that increasing the WOB leads to a subsequent increase in DOC and ROP. Furthermore, increasing the WOB also leads to increases in cutting sizes as well as material anisotropy. At Memorial University in Newfoundland, Canada, the Drilling Technology Laboratory (DTL) has developed a passive vibration-assisted rotational drilling (p-VARD) tool which enhances drill rates of penetration (ROP) in lab tests. Previous lab experiments, including simulations, point to axial vibrations having significantly improved ROP. These experiments are carried out by applying the Discrete Element Method (DEM) simulation, using the DTL p-VARD configurations tool. To gauge the tool’s cutting efficiency, a PFC2D (i.e., particle flow code in two dimensions) numerical model is utilized in simulating micro-crack generation/propagation for the drill procedure on synthetic rocks. The pVARD tool compares the downhole vibration with the rigid drill configuration of conventional rotary drilling, using low, medium and high spring compliance. Next, output parameters for ROP, MSE, and DOC are analyzed for pVARD/ non-pVARD configurations. The overall results point to the pVARD tool having a positive impact in downhole drilling, showing improvements in DOC, MSE, and ROP

Computational intelligent impact force modeling and monitoring in HISLO conditions for maximizing surface mining efficiency, safety, and health

Shovel-truck systems are the most widely employed excavation and material handling systems for surface mining operations. During this process, a high-impact shovel loading operation (HISLO) produces large forces that cause extreme whole body vibrations (WBV) that can severely affect the safety and health of haul truck operators. Previously developed solutions have failed to produce satisfactory results as the vibrations at the truck operator seat still exceed the “Extremely Uncomfortable Limits”. This study was a novel effort in developing deep learning-based solution to the HISLO problem. This research study developed a rigorous mathematical model and a 3D virtual simulation model to capture the dynamic impact force for a multi-pass shovel loading operation. The research further involved the application of artificial intelligence and machine learning for implementing the impact force detection in real time. Experimental results showed the impact force magnitudes of 571 kN and 422 kN, for the first and second shovel pass, respectively, through an accurate representation of HISLO with continuous flow modelling using FEA-DEM coupled methodology. The novel ‘DeepImpact’ model, showed an exceptional performance, giving an R2, RMSE, and MAE values of 0.9948, 10.750, and 6.33, respectively, during the model validation. This research was a pioneering effort for advancing knowledge and frontiers in addressing the WBV challenges in deploying heavy mining machinery in safe and healthy large surface mining environments. The smart and intelligent real-time monitoring system from this study, along with process optimization, minimizes the impact force on truck surface, which in turn reduces the level of vibration on the operator, thus leading to a safer and healthier working mining environments --Abstract, page iii

DEM study of particle scale and penetration rate on the installation mechanisms of screw piles in sand

Screw piles are efficient anchors to sustain large uplift loads and can be installed with low noise or vibration. Screw piles dimensions are currently increasing, renewing research interest to reduce the installation requirements (torque and crowd or vertical force). The Discrete Element Method (DEM) is an ideal technique to investigate the complex soil behaviour during screw pile installation. Different techniques such as particle upscaling or increase of pile penetration rate have been used to reduce the CPU time to more acceptable durations (e.g. few days or weeks). This paper investigates how such techniques can affect the accuracy of the results and change the installation mechanisms. Results show that maintaining a low particle scaling factor is essential to reproduce the correct mechanism at low pile advancement ratio (AR, defined as the vertical displacement per rotation divided by the helix pitch). The pile overflighting (AR≤1) creates an upwards movement of particles, which in turn creates some tension in the pile. Smaller advancement ratios require smaller particles to accurately capture this effect. Results also show that the pile penetration rate must be maintained relatively low to avoid spurious inertial effects

Influence of formation anisotropy and axial compliances on drilling performance

Drilling provides the path to reach and exploit underground oil and gas reserves. Drilling oil and gas wells can be vertical, inclined, or horizontal. However, as non-vertical drilling has become dominant, success in increasing oil and gas production has been led by horizontal drilling. Trajectories of horizontal wells have three main curvature segments: vertical, inclined (diagonal or oblique), and horizontal, where the properties of the encountered formation during drilling may vary with inclination. Rocks, classified as anisotropic (i.e. shale), whose properties are directional dependent or classified as isotropic (i.e. fine-grained and sandstone), whose properties are not directional dependent, have high influence on drilling performance, especially in nonvertical drilling. The significant shift towards horizontal drilling has increased the interest in laboratory studies and research on directional drilling, particularly in shale, to evaluate the influence of anisotropy orientation on drilling performance (i.e. ROP), and therefore, choose optimal trajectory, enhance performance, and reduce costs. This dissertation focuses on: (i) developing an experimental procedure for classifying rock anisotropy through oriented physical, mechanical, and drilling measurements, (ii) evaluating the influence of shale (as VTI rocks) anisotropy orientation on drilling parameters, and (iii) investigating the enhancement of the drilling rate of penetration (ROP) by implementing the novel drilling technique of passive Vibration Assisted Rotary Drilling (pVARD). First, a laboratory baseline procedure was developed for a rock anisotropy characterization involving oriented physical, mechanical, and drilling tests on rock like materials (RLM). This research objective was to develop the procedure on synthetic rocks (RLM) as well as natural rocks, including shale, granite, and sandstone. Second, detailed oriented physical, mechanical, and drilling measurements were taken for the determined isotropic and non-isotropic rocks in stage I, then aimed to interlink all results of all measurements, through which isotropic rock classifications can be enriched, and confirmed. Third, compliant (i.e. pVARD) versus non-compliant (without pVARD) drilling was performed in various rocks for the purpose of evaluating the influence of axial oscillations on drilling performance. Also, the parameters behind enhancing ROP with compliant versus non-compliant were investigated in this research. Last, a relationship between oriented strength and oriented drilling parameters for isotropic and anisotropic rocks was developed. This research aims to establish relationships between strength variation, drilling performance, and the main drilling parameters that influence ROP in different rock types for the purpose of rock isotropy / anisotropy evaluation

Understanding the Mechanism of Abrasive-Based Finishing Processes Using Mathematical Modeling and Numerical Simulation

Recent advances in technology and refinement of available computational resources paved the way for the extensive use of computers to model and simulate complex real-world problems difficult to solve analytically. The appeal of simulations lies in the ability to predict the significance of a change to the system under study. The simulated results can be of great benefit in predicting various behaviors, such as the wind pattern in a particular region, the ability of a material to withstand a dynamic load, or even the behavior of a workpiece under a particular type of machining. This paper deals with the mathematical modeling and simulation techniques used in abrasive-based machining processes such as abrasive flow machining (AFM), magnetic-based finishing processes, i.e., magnetic abrasive finishing (MAF) process, magnetorheological finishing (MRF) process, and ball-end type magnetorheological finishing process (BEMRF). The paper also aims to highlight the advances and obstacles associated with these techniques and their applications in flow machining. This study contributes the better understanding by examining the available modeling and simulation techniques such as Molecular Dynamic Simulation (MDS), Computational Fluid Dynamics (CFD), Finite Element Method (FEM), Discrete Element Method (DEM), Multivariable Regression Analysis (MVRA), Artificial Neural Network (ANN), Response Surface Analysis (RSA), Stochastic Modeling and Simulation by Data Dependent System (DDS). Among these methods, CFD and FEM can be performed with the available commercial software, while DEM and MDS performed using the computer programming-based platform, i.e., "LAMMPS Molecular Dynamics Simulator," or C, C++, or Python programming, and these methods seem more promising techniques for modeling and simulation of loose abrasive-based machining processes. The other four methods (MVRA, ANN, RSA, and DDS) are experimental and based on statistical approaches that can be used for mathematical modeling of loose abrasive-based machining processes. Additionally, it suggests areas for further investigation and offers a priceless bibliography of earlier studies on the modeling and simulation techniques for abrasive-based machining processes. Researchers studying mathematical modeling of various micro- and nanofinishing techniques for different applications may find this review article to be of great help

Investigation of drilling performance and penetration mechanism using passive vibration assisted rotary drilling technology

Drilling performance is an essential goal in the petroleum and mining industry. Drilling Rate of Penetration (ROP) is influenced by the operating parameter: torque, Weight on Bit (WOB), fluid flow rate, Revolution per Minute (rpm), rock related parameters (rock type, rock homogeneousness, rock anisotropy orientation), and mechanical parameters (bit type, configuration of the Bottom Hole Assembly (BHA)). The Drilling Technology Laboratory (DTL) at Memorial University of Newfoundland has incorporated the passive Vibration Assisted Rotational Drilling Technology (pVARD) as a drilling tool. This tool includes three parts within a compliant part, a part that dampens and a torque transmitting unit that is inside the BHA of the drill string. This tool utilizes the natural vibrations of the drilling process to increase drilling efficiency and rate of penetration. In this thesis, laboratory and field drilling tests have been conducted by first and second generation pVARD tools respectively which could play a positive role in improving drilling penetration rate through modified bit-rock compliance from conventional drilling. This research aims to develop a fundamental guideline for rock strength measurement and to interlink mechanical tests for the purpose of evaluating drilling performance. The compressive rock strength has an inverse relationship with drilling efficiency. The average Unconfined Compressive Strength (UCS) and Indirect Tensile Strength (ITS) of the granite were obtained to be 168.4 MPa and 16.3 MPa respectively by the mechanical loading frame in the laboratory parameters following American Society for Testing and Materials (ASTM) standard. The pVARD operational details are important for optimal configuration and best drilling results. The study focused on designing pVARD to be consistent with a Large Drilling Simulator (LDS) selecting optimal Belleville springs. Compression tests and numerical studies have been carried out using a mechanical frame and simulation analysis respectively, for different Belleville Spring stacking scenarios. Mechanical and simulation studies with details of pre-planned drilling experiments can provide important guidelines for optimizing pVARD basics. The hysteresis effect analysis of LDS-pVARD springs also provided a coherent idea of energy dissipation during the cycle test. Depending on the rock type and drilling parameters can provide pre-settings and configurations of pVARD for optimal drilling performance. Finally, this dissertation focuses on the effects of vibration on the performance of a diamond coring bit when drilling on hard rock with a first-generation small lab scale vibration tool pVARD. Thereafter, Drill off Tests (DOTs) have been performed using a Small Drilling Simulator (SDS) with axial vibrations on the drill string in laboratory conditions. The vibration properties have been adjusted to various settings of spring compliance and dampening (rubber) material. The results of the evaluation of the experimental data show that the ROP increased by a maximum of 28% keeping WOB within the operational limits. The results and knowledge obtained from this study will help to design third generation pVARD tools

New Advances in Oil, Gas and Geothermal Reservoirs

The demand for global fossil energy continues to be strong, meaning that the exploitation of oil and gas resources is still very important. In addition, due to the continuous reduction in conventional oil and gas recoverable resources, the development of unconventional oil and gas resources and geothermal energy has gradually become an important replacement. Therefore, it is urgent to improve the existing mechanism analysis, research methods and engineering technology to improve the production and development efficiency of oil, gas, and geothermal resources. This reprint presents 11 recent works on the application of new theories and technologies in oil, gas, and geothermal reservoirs. The content covers well-drilling, cementing, hydraulic fracturing, improved oil recovery, conformance control, and geothermal energy development. The new progress presented in this reprint will help scientists and researchers to better understand and master the latest theories and techniques for oil, gas, and geothermal reservoirs, which has important practical significance for the economical and effective development of oil, gas, and geothermal resources