Drill Bit Research Articles

Reducing delamination risk with response surface methodology-supported drilling analysis for Nomex® aramid fiber composites

This article presents a comprehensive experimental investigation into the drilling behavior of Nomex®, a type of aramid fiber. The study specifically examines the impact of various cutting parameters and drill bit types on drilling outcomes. While Nomex® offers many advantages, difficult chip evacuation during drilling of aramid fiber composites can lead to surface defects and delamination. The research aims to explore how drilling parameters—such as spindle speed, feed rate—and four distinct drill bit types affect drilling performance. The analysis encompasses factors such as thrust force, torque, and surface roughness, studied under different drilling conditions and with various drill bit types. Moreover, the research assesses peeling and push-out delamination factors to gain insights into drill bit and coating characteristics. An examination of burr and chipping further enhances the comprehension of drilling performance. To determine the most effective drilling conditions, the study employs multi-response optimization. The optimal drilling performance is achieved with a combination of a 0.1 mm/rev feed rate, 1402.82 r/min spindle speed, and HSS-TiN drill type. This configuration successfully integrates responses, resulting in a composite desirability value of 0.95.

Wear Prediction of Rock Drill Bits Based on Geomechanical Properties of Rocks

Wear Prediction of Rock Drill Bits Based on Geomechanical Properties of Rocks

New method prediction of rock mechanics parameters in drilling process based on machine learning

During the drilling process, rock mechanics parameters (RMP) are an important basis for optimizing drilling fluid density, drill bit selection, and wellbore stability. However, during the actual drilling, traditional methods cannot obtain the RMP of arbitrary wellbore sections. To solve the problem of RMP, a novel data-driven method for predicting RMP is proposed. Initially, the Pearson correlation coefficient method is used to analyze the correlation between the drilling data of the actual well and the label of RMP obtained by logging. And the major influence factors (e.g., drilling pressure, drilling speed) of RMP are chosen during drilling. Subsequently, three machine learning models of RBF, BP and KNN integrating the major influence factors of RMP are established. Furthermore, based on actual drilling parameters and RMP data as labels, the model is trained and verified, and hyperparameters are optimized. The results show that the RBF neural network exhibited strong generalization ability, achieving an accuracy of 87.69%. Compared to BP and KNN, the optimal model RBF neural network prediction accuracy is 4.74% and 6.13% higher. The new method of data-driven RMP prediction is of great significance in guiding drill bit selection and borehole stability during drilling.

Critical thrust force prediction in unidirectional CFRP drilling: An analytical modeling approach

In recent trends, unidirectional carbon fiber laminates have been extensively used in the aviation sector due to their remarkable material properties. Delamination is a major damage introduced during drilling in composite laminates. One of the prime contributing factors for delamination-induced damages is considered as the thrust force. A mathematical model is proposed using an analytical approach for accurate prediction of the thrust force for the last lamina, which experience the most damage. The linear elastic fracture mechanics (LEFM), the classical bending plate theory (CPT) and the theory of elastic behavior of composite lamina are taken into consideration for the proposed analytical model because numerical prediction greatly depends on material properties and the nature of force as well. In the current research, the mathematical equation is proposed based on assumption of combined loading of drill tip and chisel edges for the elliptical delaminated area. The Mode-I interlaminar fracture toughness of unidirectional CFRP (CTC1-FUD160/CT-E556) is experimented with as per ASTM D5528 for better experimental substantiation of the proposed model. When the outcomes of the proposed model are compared with the experiment results and available literature as well, a plausible relationship between the suggested analytical model and the experimental results is found. The result also reveals that the contribution of the drill tip is more profound than the chisel edges of drill bit in drilling operations.

A New SJ* Value Based on Sievers’ J-Miniature Drill Tests to Determine the Drillability of Limestones

This research presents a new drillability value (SJ*) that corrects the most-used Sievers’ J-value (SJ) by removing the accommodation effect of the drill bit in the first tenths of a millimetre to better represent the real drillability of limestones. Moreover, this research demonstrates how such an effect is more notable when porosity and micro-cracking increase, which in this study has been achieved by inducing thermal damage in the samples. To do so, limestone samples from the Prada formation were subjected to temperatures of 105, 300 and 600 °C and then cooled at fast and slow rates to induce porosity and micro-cracking. Two characteristic zones were identified in the penetration–time plots: (a) a shallow region (Zone 1) with a variable drilling rate including an initial peak and (b) a deeper region (Zone 2) where the drilling rate stabilises. These drilling rates increase with thermally induced porosity and micro-cracking, and the authors propose a new method to delimit Zones 1 and 2. Zone 1 is attributed to the time it takes for the drill bit to adjust and settle in the rock surface, while Zone 2 more realistically represents the drillability of the material. The above influences the SJ value derived from Sievers’ J-miniature drill tests, so a new drillability value SJ* is proposed that corrects SJ by excluding Zone 1 and giving more weight to Zone 2. The novel SJ* presented in this research constitutes a more accurate tool to assess and predict the drilling performance in limestones.

КОНТРОЛЬ НАПРУГИ ЗАНУРЮВАНИХ ЕЛЕКТРОДВИГУНІВ

The methods and means of voltage control on the clamps of submersible electric motors of electric drills are considered. The peculiarities of the submersible electric motor as a consumer of electrical energy when it is powered by three-phase voltage via a cable line with asymmetric electrical resistances of the phases are revealed. The main downhole factors influencing the functioning of the submersible electric motor that rotates the drill bit during drilling of deep oil and gas wells are analyzed. The impact of the temperature of the drilling fluid on the value of the active resistance of the cable cores and the drill pipe in deep drilling conditions has been updated. The results of the analysis of known technical solutions and concepts regarding the possibility of voltage control on the clamps of submersible motors, which would implement its physical measurement in industrial conditions, are presented. A method of analytically calculating the phase voltages on the clamps of the submersible electric motor of the electric drill, which is powered by an electric cable with asymmetric electric resistances of the phases, is proposed. The possibility of practical implementation of a laboratory installation based on the proposed method of calculating phase voltages on the clamps of the submersible electric motor of an electric drill is shown. For the practical implementation of the method of analytical calculation of phase voltages on the clamps of a submersible electric motor, the feasibility of using digital processing of signals from current and voltage transmitters located on the surface during oil or gas well drilling is substantiated. The advantages of the proposed method of controlling the voltage on the clamps of the submersible electric motor of the electric drill are the consideration of the electrical parameters of specific power supply cables obtained as a result of auxiliary measurements, and the possibility of technical implementation on a modern element base. The development and implementation of a device for monitoring phase voltages on the clamps of the submersible electric motor of an electric drill will increase the operational reliability and efficiency of drilling wells with an electric drill, which will reduce their cost.

Research on friction characteristics of the support mechanism of the drilling robot under axial-torsional load

Because the coiled tubing drilling robot (CTDR) needs to pull the coiled tubing (CT) and provide the weight on bit (WOB), the traction force is an essential parameter for evaluating the performance of the CTDR. The friction performance between the support mechanism of the CTDR and the borehole wall will directly affect the traction force. At present, there is not a research paper about the mechanical behavior of the interaction between the support mechanism and the borehole wall. On this basis, a model of contact mechanics of the friction block of the support mechanism and the borehole wall was established. The model of contact mechanics integrates the combined factors of the torsional forces and axial forces generated by the drill bit and the CTDR. The friction performance between the friction block of the support mechanism and the borehole wall under different parameters and conditions was investigated. It is found that the size of the rake angle of the tooth has little effect on the damage of the borehole wall only under normal force. And, the rake angle of the tooth is negatively correlated with the equivalent friction coefficient. The embedded depth is positively correlated with the equivalent friction coefficient. When the rake angle of the tooth is greater than 35°, the influence of the embedded depth on the equivalent friction coefficient is weakened. When the embedding depth of the friction block reaches 0.3 mm, the equivalent friction coefficient is greater than 1. When the bevel angle of the tooth is 20°, the friction block performs best. The optimized structural parameters of the friction block are as follows: rake angle of the tooth of 35°, back angle of 60°, spacing of 4 mm, and bevel angle of the tooth of 20°. Further contact experiments were conducted between a single tooth of the friction block and a rock sample. The differences between the experimental results and the numerical simulation results were analyzed. The correctness of the theoretical model is verified by experiments. This paper reveals the relationship between structural parameters and equivalent friction coefficient. The results can provide a theoretical basis for the structural design of the friction block for high-safety and high-traction CTDR.

An Invention Shading Light to the Socio-History of Bonneuil Quarry Basin: The Roadheaders with Rotating Drill Bits

Abstract The Bonneuil quarry basin is located in the North-East of Paris; it played a role in the well-known stone trade for Paris and its surroundings in the nineteenth and the beginning of the twentieth centuries. Stonecutters of this area mainly used the extraction with the lance, a long iron spin bear by a scaffolding. This tool helped the quarrymen speed up their work allowing them to be competitive in trading. At the end of the 1930s, Martial Lefèvre, a wealthy owner of quarries in the Bonneuil’s basin, created a machine, roadheaders with rotating drill bits, following the movement of his quarrymen using the lance. The story of this machine was also involved in the Second World War and the occupation of France. Merging modern archaeology, history, and archaeology of technique, the aim of this paper is to explore the transition between hand tools and mechanical tools through the chaîne opératoire filter, a subject that is currently little studied. It also crossed the path of the delicate story of a small industry during one of the most events in France, the Second World War. Using it as an example, this article questions the status of these quarries during and after this main event.

Hole Cleaning during Drilling Oil and Gas Wells: A Review for Hole-Cleaning Chemistry and Engineering Parameters

Efficient hole cleaning during drilling operations is critical to maintain a high rate of penetration and smooth drilling, leading to minimum drilling problems and economical drilling efficiency. This process involves several important factors, including pipe-sticking incidents, higher cuttings concentrations in the annulus, noisy vibration of the drill string, erratic equivalent circulating density, lost circulation incidents, well control incidents, geomechanical hole section instability, tight spots during tripping operations, and excessive usage of chemical additives for conditioning hole sections and mud. Various approaches, including correlations, methodologies, developments, algorithms, equipment, charts, field experience, chemicals, and studies involving experiments, can be used to enhance the efficiency of hole cleaning. The development of hole-cleaning models is important for use as hole-cleaning indicators to ensure optimized drilling efficiency. This paper presents a comprehensive overview of the complex field of hole cleaning in the oil and gas industry. It includes techniques, tools, models, and chemical additives. It also encompasses drilling engineering, operations, and chemistry. To facilitate the transit of drill cuttings, maintain hole section stability, cool and lubricate the drill bit, and transmit hydraulic horsepower, this article outlines the important roles of drilling fluids. The significance of chemical additives, including nanoparticles, natural and modified polymers, and synthetic polymers, in preserving wellbore stability, improving drilling efficiency, and lowering drill bit wear is also covered in the study. It concludes by making recommendations for further study to clarify hole cleaning for the reader to facilitate and boost drilling efficiency.

A drilling combination positioning method based on geomagnetic/inertial navigation combined with PSD improved unscented Kalman filtering algorithm*

During the drilling process, the accuracy of measuring drilling tool attitude is severely affected by measurement drift errors in the inertial device itself and the significant interference noise generated by the impact vibration of the drill bit. To address these issues and achieve precise measurement of drilling trajectory, this paper proposes a combined positioning method based on geomagnetism/inertial navigation combined with PSD improved unscented Kalman filtering. An experimental platform was constructed, and a sensor system was installed in the vicinity of the drill bit for short section measurements. Experimental verification was conducted using actual drilling data. The results demonstrate that, compared to general unscented Kalman filtering, the average position error using PSD improved unscented Kalman filtering was reduced from 0.122 m to 0.088 m, and the average velocity error was reduced from 0.019 m s−1 to 0.005 m s−1. By comparing and matching with the drilling trajectory drawn in the logging process, the overall positioning accuracy of the combined positioning method is as high as 90.8%, yielding positioning results that are highly authentic and effective, thereby meeting the on-site usage requirements.

Investigation of field scenarios using a 4n degrees of freedom transient torque and drag model

A coupled drill string dynamics model presents an opportunity to understand, replicate and potentially control the vibrations occurring along a drill string in a deep well. This paper describes a 4n degrees of freedom (4nDOF) model of the axial, torsional and lateral dynamics, consisting of coupled wave equations and lumped elements, which include modeling of the contact between the drill string and wellbore with a stiff string assumption. The model accounts for the bit-rock interaction, structural damping, and hydraulic forces acting on the lumped elements. The 4nDOF model is compared with three field scenarios from a drilling operation in the North Sea: a three-stage top drive start-up procedure, a drilling sequence starting from off-bottom conditions, and a backreaming operation at low rotational speed. The selected cases include instances of stick–slip and higher modes of torsional vibrations, which persist despite the use of a surface vibration mitigation system. High-frequency data recorded by a downhole measurement sub placed near the drill bit are used to verify the simulated downhole rotational speed and triaxial accelerations. The model is useful for analyzing torsional stick–slip events, which are replicated with a similar period and amplitude as in the downhole measurements. Furthermore, the model accurately reproduces the transition between first and second mode torsional oscillations upon the activation of a tuned top drive vibration mitigation system. The model can also be used to analyze lateral deformations and whirling of the drill string at various depths. The field case simulations show that the lateral dynamics can undergo significant changes at certain points in the drill string during torsional stick–slip and higher-mode torsional oscillations. The proposed model can be used to run simulations in close to real-time on a standard personal workstation, thus making it a valuable tool for devising and testing new drill string vibration mitigation solutions.

Stick–Slip Vibration Characteristics Study of the Drill String Based on PID Controller

In order to address the issue of drill string stick–slip vibration, which leads to drill bit wear and reduces the drilling velocity, we conducted a study on the characteristics of stick–slip vibration using a proportional-integral-derivative (PID) controller. By applying the principles of rigid body mechanics, we established a two-degree-of-freedom torsional dynamics equation and derived the first-order differential dynamics equation for the drill string. Subsequently, we designed a PID controller and obtained an equation for the control of stick–slip vibration. The research findings indicate that variations in the difference between the static and dynamic friction coefficients directly impact the nature of the limit cycles in the phase plane. As this difference decreases, the limit cycle narrows and the stick–slip vibrations weaken progressively. When the static and dynamic friction coefficients are equalized, no stick–slip vibrations occur within the drill string. The implementation of PID control effectively manages stick–slip vibrations in the drill string, with greater efficiency observed in controlling the turntable velocity compared to the drill bit velocity. This research provides valuable insights for the development of control strategies aimed at mitigating stick–slip vibrations in drilling engineering applications, thereby facilitating the efficient and safe extraction of oil and gas resources.

Dynamic characteristic response of PDC bit vibration coupled with drill string dynamics

A thorough understanding of the rock breaking process is key to increasing the rate of penetration and reducing bit wear. Currently, many models of drill bit–rock interaction have been developed. However, these models inaccurately reflect the complex movement of polycrystalline diamond compact (PDC) bits in the well. In this study, the finite element method was used to discretize and simulate the rock removal process, and drill string nodes were taken as the boundary conditions of drill bit movement. A model combining drill string dynamics and drill bit–rock interaction was established to describe the complex dynamic behavior of a PDC bit in a well. The accuracy of the model was verified by a PDC bit drilling experiment. Then, the influences of rock type, weight on bit (WOB), rotational speed, and PDC bit blade number on PDC bit vibration characteristics were studied. Results show that drill bit vibration is stronger when drilling in rocks with high hardness and roughness, and the bit runs more smoothly with more blades. Therefore, drill bits with more blades should be used when drilling hard rocks. Bit vibration is enhanced by increasing rotational speed and WOB, but the effect of rotational speed on bit vibration is much smaller than that of WOB.

Research on sealing mechanism and structural improvement of metal sealing structures for high speed drill bits

The main causes of metal seal failure are studied and the main judgment criteria for metal seal failure are provided based on the structural characteristics in this paper. Mechanical analysis is conducted on the assembly and compression process of single metal seals, and the theoretical relationship between the contact pressures of the dynamic sealing surface of single metal seals is obtained. The finite element software was adopted to simulate the assembly process of a single metal seal. The results show that the sealing washer limited the downward deformation of the energy supply ring. The stress is concentrated at the chamfer at the lower end of the original sealing washer and metal ring, which is leading to the failure of the sealing washer. The new sealing structure can not only enhance the function of the energy supply ring on the metal sealing force, but also reduce the normal force of the sealing washer. It is concluded that the new sealing structure can improve the bearing sealing performance of small-sized cone drills through on-site drilling experiments. The conclusion has a certain guiding effect on the design and application of high speed bit.

Drill Bit Selection and Drilling Parameter Optimization using Machine Learning

Machine Learning (ML) Algorithms have demonstrated their tremendous application in optimizing and enhancing the performance of various complex operations in the field of science and technology. In this research work, ML is applied to address two of the most critical factors affecting the drilling performance in the Oil and Gas Industry, which are drilling bit selection and drilling parameters optimization. Rate of Penetration is a key performance indicator of drilling efficiency, higher ROP signifies higher drilling efficiency. In this research work, a hyperparameter tuned Random Forest Regressor algorithm with an accuracy of 0.73 based on the coefficient of determination i.e., R2 Score, is used to develop ROP prediction model and subsequently drill bit selection and drilling parameters optimization is performed using Particle Swarm Optimization. The developed model has practical applicability in the selection of drill bit and optimization of drilling parameters in the Oil and Gas field. Higher ROP results in less drilling time, which correspondingly results in less capital expenditure on the project.

Technology Focus: Bits and Bottomhole Assemblies (December 2023)

As bottomhole-assembly and drill-bit design and operation have embraced new technologies such as artificial intelligence, new materials and manufacturing techniques, and improved design software, the industry continues to research methods of optimizing delivery and understanding of already globally used technologies. It is this approach that has long allowed service companies, operators, and drilling contractors alike to improve drilling performance, as highlighted in the papers summarized here. In the first of these papers, paper SPE 210723, finite element fatigue simulation has been used to minimize the risk of twistoffs in jars, something that many of us in the drilling community have experienced. This paper can help us reduce those unplanned events and lost time. Many rigs worldwide have moved to using autodriller-type control systems, and, in many cases, these systems have shown improved performance. In the second paper, paper SPE 214997, the optimization of these systems is discussed in the review and modification of driller procedures to minimize damage to bottomhole assemblies and the drill bit during drilling. Finally, while many papers have discussed high-frequency torsional oscillations and their effect on the bottomhole assembly and drill bit from an operational or a theoretical view point, the final paper, paper SPE 212566, discusses full-scale laboratory experiments to qualify the drill bit’s influence on this effect. All three of these papers highlight increased understanding in the operation and evolution of existing technologies to improve drilling delivery. In the evolving world of drilling where the final objectives and uses of wells are changing—whether for repurposing; carbon capture, use, and storage; or geothermal uses—these approaches to optimizing existing technologies in conjunction with the introduction of new technologies can help oilfield drilling teams pivot into this adjacent energy environment to deliver successful wells. Recommended additional reading at OnePetro: www.onepetro.org. SPE 212438 Building a System To Solve the Challenges of Drilling Hot Hard Rock for Geothermal and Oil and Gas by Anthony Pink, NOV, et al. SPE 212559 Machine Learning-Based Drilling System Recommender: Toward Optimal BHA and Fluid-Technology Selection by Gregory Skoff, SLB, et al. SPE 212109 World’s First Application of Steel Body Bit in High-Chloride Formation With Water-Based Mud by Bekbolat Uandykov, Zhigermunaiservice, et al.

Characterization of 10 nm – 10 μm coal dust particles generated by simulated different cutting and drilling parameters: mass concentration distribution, number concentration distribution, and fractal dimension

Nano-to-micron-sized coal dust can cause coal workers’ pneumoconiosis (CWP), and cutting and drilling are the main coal dust-generating processes. Based on a self-developed simulated coal cutting and drilling dust generation system, the effects of cutting parameters (tooth tip cone angle, impact angle, roller rotary speed, cutting speed) and drilling parameters (drill bit diameter, drilling speed) on the mass concentration distribution, number concentration distribution and fractal dimension of 10 nm – 10 μm coal dust were investigated. Results show that the mass concentration of 10 nm – 10 μm coal dust generated by cutting/drilling peak at 5.7 – 7.2 μm, while the number concentrations during cutting and drilling respectively peak at 60 – 90 nm and 20 – 30 nm. During both cutting and drilling processes, the generated coal dust particles in 10 – 300 nm account for > 90% of the total 10 nm – 10 μm coal particles, while PM2.5 in PM10 is generally below 18%. It is also found that smaller tooth tip cone angle, larger impact angle, lower roller rotary speed, smaller drill bit diameter, or lower drilling speed can reduce the generation of 10 nm – 10 μm coal dust with a fractal dimension of 0.94 – 1.92. This study reveals the distribution characteristics of nano- to micron-sized coal dust particles under different cutting and drilling parameters, and the research results can serve as reference for adjusting cutting and drilling parameters to lower down the 10 nm – 10 μm coal dust generation and thus prevent the CWP.

Masquelet Technique: Visualization of Cement Spacer Utilizing Methylene Blue

Masquelet Technique: Visualization of Cement Spacer Utilizing Methylene Blue

InAsSb Photodiode Fibre Optic Thermometry for High-Speed, near-Ambient Temperature Measurements

Infrared radiation thermometers (IRTs) overcome many of the limitations of thermocouples, particularly responsiveness and calibration drift. The main challenge with radiation thermometry is the fast and reliable measurement of temperatures close to room temperature. A new IRT which is sensitive to wavelengths between 3 μm and 11 μm was developed and tested in a laboratory setting. It is based on an uncooled indium arsenide antimony (InAsSb) photodiode, a transimpedance amplifier, and a silver halogenide fibre optic cable transmissive in the mid- to long-wave infrared region. The prototype IRT was capable of measuring temperatures between 35 °C and 100 °C at an integration time of 5 ms and a temperature range between 40 °C and 100 °C at an integration time of 1 ms, with a root mean square (RMS) noise level of less than 0.5 °C. The thermometer was calibrated against Planck’s law using a five-point calibration, leading to a measurement uncertainty within ±1.5 °C over the aforementioned temperature range. The thermometer was tested against a thermocouple during drilling operations of polyether ether ketone (PEEK) plastic to measure the temperature of the drill bit during the material removal process. Future versions of the thermometer are intended to be used as a thermocouple replacement in high-speed, near-ambient temperature measurement applications, such as electric motor condition monitoring; battery protection; and machining of polymers and composite materials, such as carbon-fibre-reinforced plastic (CFRP).

Supramolecular porous-based phase change material based on cucurbit[7]uril complexed amino-montmorillonite

Under high-temperature conditions, drill bits, downhole guiding tools, etc. are susceptible to failure, so capturing and storing the heat energy generated is critical for efficient drilling. In this work, a porous material of cucurbit[7]uril (CB[7]) complexed amino-montmorillonite (NH2-MT) was proposed for the first time to encapsulate eutectic nitrate (NIT) to alleviate the high-temperature crisis in the drilling process. The results showed that the structural stability and anti-leakage performance of the supramolecular composite phase change materials (MAC@NIT) were significantly improved by the addition 0.25 g of CB[7], and the adsorption of Na+ and K+ by CB[7] was in the form of monolayer adsorption. The phase change temperature and structure of MAC@NIT-2 remained stable after 200 cycles, and the maximum change of latent heat of solid-liquid was only 3.96 J/g. The special cavity structure of CB[7] further enhanced the thermal conductivity of the MAC@NIT, up to 0.48 W/m·k, which was 20 % higher than the MT@NIT. The addition of MAC@NIT improves the stability of the drilling fluids by 15 %. Additionally, the temperature of the drilling fluids could be reduced by 4.3 °C at a low solid-solid latent heat value. In summary, this study provides ideas for developing ultra-deep oil and gas resources efficiently.