Drill Bit Research Articles

Research on the mixed-mode fracture damage characteristics of shale soaked in different drilling fluids

Drilling fluid is a vital component in drilling engineering and can be considered as the lifeblood of the drilling. It serves multiple functions such as cooling the drill bit, cleaning the wellbore, and maintaining wellbore stability. However, when the drilling fluid penetrate into the formation, it significantly reduces the mechanical properties of the rocks thus making the wellbore prone to instability. This paper focuses on the studying the fracture characteristics of shale samples with different pre-crack angles (15°, 30°, 45°) when immersion in different types of drilling fluids (water-based drilling fluid, alcohol-based drilling fluid, oil-based drilling fluid) using the SCB (Semi-circular bending) test. During the experiment, digital image correlation and acoustic emission techniques were employed to monitor and analyze the fracture characteristics of shale. The research findings showed that as the pre-crack angle increases, the fracture toughness and effective fracture toughness of Mode I fractures decrease continuously, while the fracture toughness of Mode II fractures gradually increases. The impact of drilling fluids on the fracture toughness of shale samples is in the following order: water-based drilling fluid > alcohol-based drilling fluid > oil-based drilling fluid. The length of the fracture process zone (FPZ) decreased with the increase of the pre-crack angle, and the FPZ length under different drilling fluid immersion shows varying degrees of enlargement, with the following effect: water-based drilling fluid > alcohol-based drilling fluid > oil-based drilling fluid. The horizontal strain and horizontal displacement generated before the rock sample fractures increase with the increasing angle of the pre-crack. After immersion in drilling fluid, the layering of horizontal displacement field becomes more evident, with the degree of straightness of horizontal displacement affecting it in the following order: oil-based drilling fluid > alcohol-based drilling fluid > water-based drilling fluid. As the pre-crack angle of the SCB sample gradually increases, the relative decrease in acoustic emission energy becomes more pronounced, and the decrease in b-value becomes more significant. After immersion in drilling fluid, the acoustic emission becomes more pronounced, and the b-value becomes more disorderly and decreases further. Finally, by analyzing the fracture patterns of SCB samples immersed in different drilling fluids, relevant fracture mode diagrams were established. The findings could be useful in developing strategies for optimizing drilling fluid selection and fracture stimulation design in shale formations.

Multiphase simulation of sustainable nanoenhanced ionic liquid coolants for improved thermal performance in Ti–6Al–4V alloy drilling

Extensive research has been conducted by the manufacturing industry to enhance the efficiency of drilling processes by focusing on the utilization of nanoenhanced cutting fluids that possess excellent heat conductivity. Due to their eco-friendliness and adaptability of physical and chemical properties, ionic fluids offer enormous potential for application as cutting fluids. This study investigates the computational fluid dynamics analysis of the heat transfer performance of various ionanofluid pairs dispersed with nanoparticles as cutting fluids in the drilling process using Ansys Fluent software. For this purpose, 1-Hexyl-3-methyl-imidazolium-tetrafluoroborate is considered the ionic fluid, and its thermal behavior is examined by dispersing it with nanoparticles of copper, silver, and multiwalled carbon nanotubes (MWCNT) at different particle volume fractions and Reynolds numbers. The workpiece is composed of an alloy of titanium Ti–6Al–4V, while the drill bit is made of tungsten carbide-cobalt. It is observed that the ionic nanocoolant mist emanates from the spray tip and moves towards the drill bit-workpiece interface. Initially, the coolant's velocity is greatest close to the orifice, and as time passes, it approaches the drilling space. The data indicates that the spraying velocity of the coolant augments over time and that it disperses heat at the tool-chip interface. The results help us validate the flow and interaction of ionanocoolant with the drilling zone. With a rise in the volume fraction of added nanoparticles and Reynolds number, the results indicated a significant decrease in the drilling temperature. With a higher particle volume fraction, the MWCNT-ionic coolant combination decreases the drilling temperature of pure ionic liquid by 25.64 %. The copper, silver, and MWCNT ionanofluids enhance the average heat transfer coefficient of pure ionic coolant by 35.14 %, 47.42 %, and 62.75 %, respectively. In addition, MWCNT nanocoolants demonstrated improved thermal performance and heat removal rate in comparison to copper and silver ionanocoolants.

Measuring and modeling the tool path of the small-sized drill bit in wood-based materials

ABSTRACT The aim of this study was to investigate the trajectory of a hole drilled using a small-dimension drill bit (0.5 mm) in wood-based materials. Computer vision was used to determine the three-dimensional position of the hole. Scans were made to a depth of 5 mm every 0.5 mm (access to subsequent layers was obtained by milling with three three-blade cutter with a diameter of 26 mm). The obtained results allowed us to determine the parameters of the obtained hole, allowing to correlate the quantities, such as deviations (initial, relative, total) and angle of relative azimuth. A good correlation (R2 > 0.75) between total deviation and initial deviation for medium-density boards and hardboards can be found. The initial deviation of the drill determines the direction of the tool into the material and the initial deviation forces a specific direction of further deviation.

An algorithm to improve magnetic ranging accuracy for cluster horizontal wells with narrow spacings

In order to realize the efficient development of unconventional oil and gas, the measurement accuracy of wellbore spacing in the drilling of parallel horizontal wells is more and more required. Although the Rotating Magnet Ranging System or Magnetic Guidance Tool is used to achieve a good ranging effect in the drilling of dual horizontal wells, the position measurement of the magnetic sub leads to a large ranging error. A new ranging algorithm for the Two Sensor Packages-Rotating Magnet Ranging System is presented in this paper. The algorithm takes the magnetic signal generated by the rotation of the magnetic sub at a fixed position, the tilt measurement data of the two wells, the length of the magnetic sub, and the distance between the two fluxgate sensors as input parameters to avoid measuring the position of the magnetic sub and to reduce the influence of the degree of non-parallelism and the length of the magnetic sub. The simulation and experiment demonstrate that the inclination and azimuth angles of the two wells have a significant impact on the magnetic ranging results when the ranging well sections are not parallel and that the distance between the bottom of the drill bit and the center of the magnetic sub cannot be ignored. Moreover, the accuracy of the relative distance calculated by this new algorithm can reach 97%, and the error of direction calculation is less than 3°. Applying this algorithm in the field can successfully aid in controlling the spacing of cluster horizontal wells more accurately.

Do It Yourself (DIY) Radiolucent Drill Guide Using a 10 ml Syringe for Freehand Distal Interlocking in Intra-medullary Nailing: A Surgical Technique.

Distal interlocking during intramedullary femoral, tibial, and humeral nailing is frequently challenging. In the traditional image intensifier (II) 'bull's eye' technique, the implant's interlocking screw hole can be obscured by the radio-opaque chuck, necessitating multi-planar checks by tilting the drill bit before drilling. This manoeuvre can adversely alter the drill trajectory, compromise fixation, or damage the implant. We introduce a surgical technique that uses a 10 ml syringe to overcome this difficulty.

A Data-Driven Approach to Predict the ROP of Deep Wells in Fukang Sag

In the deep well drilling process in the Fukang Depression of the Eastern Junggar Basin, rock fracturing issues and low rate of penetration (ROP) have posed significant challenges to drilling efficiency. Accurate predictions of ROP prior to drilling are of considerable value in this context. Precise predictions enable on-site engineering teams to proactively identify drilling difficulties and anticipate potential complex scenarios, facilitating them in designing preventive measures in advance, such as selecting appropriate drill bits, adjusting drilling parameters, or employing specific drilling techniques to address these issues. This, in turn, enhances drilling efficiency and greatly reduces drilling risks. Traditional mechanical-specific energy drilling rate models, despite their widespread use, exhibit significant disparities with actual results when predicting ROP. These models only consider the influence of drill bits, drilling tools, and some drilling parameters on ROP, failing to adequately account for the variations caused by engineering factors and failing to capture the interrelationships between various parameters, especially when dealing with complex subsurface formations in the Fukang Depression. Random forest is a non-parametric algorithm in the field of machine learning that is suitable for analyzing and predicting ROP affected by various complex and non-linear drilling parameters. This paper establishes a Random forest model based on a dataset containing multiple variables of logging parameters and the actual ROP. The model ranks and assesses the important feature parameters of ROP to reveal their impact. Additionally, the model uses bootstrap sampling and feature random selection to construct multiple decision trees, reducing the risk of overfitting and endowing the model with a high generalization capability. Evaluation metrics indicate that the model exhibits a high prediction accuracy and performs well, significantly improving the accuracy of mechanical drilling rate predictions in the deep wells of the Fukang Depression. This model provides robust support and serves as a positive demonstration for addressing mechanical drilling rate issues in complex subsurface formations in the future.

Combining Artificial Neural Network and Response Surface Methodology to Optimize the Drilling Operating Parameters of MDF Panels

Most of the parts of furniture made of medium density fiberboards (MDF) require at least one hole to be assembled. The drilling technological parameters influence the quality of holes. Factors such as tip angle of the drill bit, feed rate, type and diameter of the drill bit, and spindle rotational speed could affect the drilling process. Therefore, the right choosing of drilling parameters is a mandatory condition to improve the drilling efficiency that is expressed through tool durability, cost, and quality of the drilling. Thus, in this work, we are proposed an approach that consists in combining two modelling techniques, which were successfully applied in various fields, namely artificial neural network (ANN) and response surface methodology (RSM), to analyze and optimize the drilling process of MDF boards. Four artificial neural network models with a reasonable accuracy were developed to predict the analyzed responses, namely delamination factor at inlet, delamination factor at outlet, thrust force, and drilling torque. These models were used to complete the experimental design that was requested by the RSM. The optimum values of the selected factors and their influence on the drilling process of the MDF boards were revealed. A part of optimum combinations among analyzed factors could be used both during the drilling of the MDF boards and prelaminated wood particleboards.

Influence of blades’ shape and cutters’ arrangement of PDC drill bit on nonlinear vibration of deep drilling system

In this paper, the surface morphology method is improved and the bit-rock interaction model between the rock and the PDC bit is studied, considering the influence of blades’ shape and the cutters’ arrangement. Based on this model, the dynamic model of the deep drilling system equipped with arbitrary shape PDC bit is established, and the stability prediction method is proposed. Based on the improved surface morphology method, the dynamic characteristics of the drilling system equipped with four different types of bit (an actual bit, a Tian bit, a Tian bit with blades, and a traditional bit) are studied, comparing with the Tian model based on polygon clipping. The results indicate that the influence of blades’ shape and cutters’ arrangement of PDC bit on the nonlinear vibration of the drilling system cannot be ignored. By applying the proposed method, the dynamic model of the drilling system equipped with an actual PDC bit presents excellent computational efficiency, accuracy, and avoids unreasonable behavior, which provides a reliable theory for the dynamic analysis of the drilling system. In addition, the proposed uncut volume error and repeated cutting volume error can be used to evaluate the shape design of the drill bit and the accuracy of the bit-rock interaction model.

Evaluation of the Wear Resistance and Electrochemical Behavior of Drill Bits for Drilling Oil and Gas Wells

This work aims to study the relation between the hardness and behavioral wear of tungsten carbide inserts (TCI) and polycrystalline diamond compact (PDC) cutters, used as drill bits for drilling oil and gas wells, through wear testing conducted using the pin-on-disc test and the measure of microhardness Knoop test. The morphology of the worn surface was characterized using scanning electron microscopy (SEM), and the chemical composition was taken before and after the wear test inside the tracks using energy-dispersive X-ray spectrometry (EDX). Additionally, the behavior of the corrosion resistance was evaluated with the electrodynamic polarization technique and was compared with a coating of diamond-like carbon (DLC) in order to determine whether this coating applied to tool steel could serve as a substitute for insert-based coatings in future applications, as its cost is lower than that of the inserts. A paragraph discusses what characteristics must be taken when selecting or manufacturing materials for drill bit applications. In conclusion, it was found that the TCI insert presented cracks in the test tracks, while the PDC insert showed soft wear; this was due to the uncertain hardness, which was greater than the indenter used. Concerning the Tafel test, the curves showed that the PDC insert presents better behavior under corrosion; however, the DLC can be a good substitute.

The Development of Advanced Fluorescent Tracers Aimed at Drill Cuttings Labelling and Depth Correlation via Injection with Oil-Based Drilling Mud

Fast and precise geo-steering and geo-navigation upon well drilling are the key parameters for improved well targeting, optimal well placement, and maximal hydrocarbon recovery. To advance geo-steering parameters, we propose a new approach to on-site formation evaluation through the use of fluorescent tracers for drill cuttings tagging according to the depth of origin. Cuttings labelling at the drill bit site is followed by near-real-time drilling depth correlation at the well-head via a camera and AI image recognition systems. To suite the drilling process, the engineered tracers should match to the rheology of the utilized drilling mud. This study was performed to comprehensively investigate the effect of fluorescent tracers on the rheological properties of oil-based drilling mud (OBM) and to determine the optimal quantities of the tracers’ addition. We evaluated critical mud characteristics including electrical stability, thixotropic parameters, shear stress, gel strength, plastic viscosity, and yield point as prepared and in the presence of fluorescent tracers at the range of 1 to 20 wt.%. Additionally, the mud’s effects on the long-term stability of the fluorescent tracers were assessed via hot-rolling tests in conditions mimicking downhole conditions, with the aim of determining the tags’ feasibility for drill cuttings labelling applications. The study also examines the recovery potential of the tracers and their reusability in the drilling process. This investigation provides valuable insights into the potential application of fluorescent tracers for downhole drill cuttings depth correlation which will improve geo-steering works.

The Influence of Internally Cooled Drill Bits on Cutting Dynamics and Workpiece Hardness Monitoring in Stone Machining

Drill bits with internal cooling capabilities are still not employed in stone machining practices within shop floor environments. Therefore, a conventional industrial drill bit used in stone machining was subject to a redesign wherein an axial cooling channel was machined throughout its body. A comparison was drawn between the standard drill bit without cooling capabilities and the redesigned drill bit, which used compressed air as a cooling medium. The experiment was performed by drilling three types of stone samples varying in hardness with nine combinations of cutting speed and feed rate. During the machining process, two types of process signals were continuously measured—namely, cutting forces and vibrations. Additionally, the cutting edges of the drill bits were inspected after a specific number of drilling cycles using a vision system. The primary objective of this study was to compare the cutting forces and tool wear dynamics achieved by those two drill bits. Furthermore, the usage of vibration signals in the classification of stone hardness during machining with an internally cooled drill bit was additionally analyzed. The results of this study unveiled improvement in minimizing cutting forces, vibrations, and the intensity of tool wear when utilizing an internally cooled drill bit. Even though the machining system generally exhibited lower vibrations, vibration signals again demonstrated commendable efficacy in classifying stone hardness.

Investigation of the drilling behavior of the Ti6Al4V alloy and developing prediction model using artificial neural network

This study investigates the influence of cutting parameters on drilling performance for Ti6Al4V alloy using TiN-coated carbide drill bits in a dry drilling environment. The surface roughness, feed force, cutting moment, cutting temperature, tool performance, hole diameter, circularity, and cylindricity values of the hole were studied. The optimal drilling parameters were determined using ANOVA to achieve the desired hole sizes, and prediction models were developed using artificial neural networks (ANN). The experimental results revealed that the feed rate was the most influential parameter for feed forces (92%), whereas the cutting speed had the greatest effect on tool performance (98%). It was determined as a result of the analyses that the optimal feed rate for tool performance, cutting moment, surface roughness, cutting temperature, and feed forces was 0.05 mm/rev. The diameter of the hole was positively affected at high cutting speeds and feed rates. The circularity and cylindricity of the hole were adversely affected by these cutting conditions. Adhesive wear was seen on the drill bits in all cutting conditions, and surface roughness was negatively affected by this adhesive wear. Artificial neural networks (ANN) were used to predict operating cost outputs (feed force, tool performance) and hole quality outputs (surface roughness, deviation of hole diameter). The compatibility of the experimental results and the ANN model was examined in the control experiment. ANN was able to predict the surface roughness and hole diameter with deviation values of 3% and 7%, respectively. Similarly, the deviation values for feed force and tool performance were determined at 3% and 10%, respectively.

Attitude Control of Stabilized Platform Based on Deep Deterministic Policy Gradient with Disturbance Observer

A rotary steerable drilling system is an advanced drilling technology, with stabilized platform tool face attitude control being a critical component. Due to a multitude of downhole interference factors, coupled with nonlinearities and uncertainties, challenges arise in model establishment and attitude control. Furthermore, considering that stabilized platform tool face attitude determines the drilling direction of the entire drill bit, the effectiveness of tool face attitude control and nonlinear disturbances, such as friction interference, will directly impact the precision and success of drilling tool guidance. In this study, a mathematical model and a friction model of the stabilized platform are established, and a Disturbance-Observer-Based Deep Deterministic Policy Gradient (DDPG_DOB) control algorithm is proposed to address the friction nonlinearity problem existing in the rotary steering drilling stabilized platform. The numerical simulation results illustrate that the stabilized platform attitude control system based on DDPG_DOB can effectively suppress friction interference, improve non-linear hysteresis, and demonstrate strong anti-interference capability and good robustness.

Drill Bit Design and Its Effect on Temperature Distribution and Osteonecrosis During Implant Site Preparation: An Experimental Approach

In this study, the drilling parameters will be evaluated to obtain optimal parameters in minimizing the impact of drilling damage on synthetic bone blocks. The effect of damage observed in the study is osteonecrosis that occurs in the drill hole for implant site preparation, where a smaller value is desired. The drilling parameters are optimized using the Taguchi method with two control factors: the feed rate and spindle speed; each parameter is designed in five levels. This experiment was then carried out on four different designs of drill bits, i.e., Twist (118°and 135°), spherical, and conical drill bits. While experimental planning uses L25 orthogonal arrays, the “smaller is better” approach is used as a standard analysis. The main findings of this research are 118° point angle twist drill bit is the ideal type of drill bit for bone drilling, as it produces less heat than other types of drill bits. The optimal range of feed rate and drilling speed for bone drilling is 40-60 mm/rev and 1000-1400 RPM, respectively. Combining these parameters helps to minimize heat generation during implant site preparation drilling.

Оценка точности метода измерения сопротивления сверлению древесины в дендрохронологических исследованиях

One of the promising methods for determining physical and mechanical properties and structure of wood is the method based on the measurement of drilling resistance. Limitations of application of the method of measuring drilling resistance in dendrochronological studies are related to a number of factors that have a significant impact on the accuracy of determining the variation of physical and mechanical properties of wood within annual layers: the depth of drilling, its direction relative to the fibers, and the speed parameters of the drilling process. In order to assess the accuracy of measuring the radial growth of pine wood (Pinus sylvestris L.) with moisture content of 6–8 %, the ResistYX device and standard thin drill bits were used. On the basis of comparative analysis of radial wood growth determined by the optical method and the method of measuring resistance to drilling, it was found that in order to obtain accurate data on growth with a correlation coefficient greater than 0.7, it is recommended to measure no more than 17 annual layers on one sample, which corresponds to an average total width of annual layers of 36.6 mm. The influence of the main reasons for the decrease in the accuracy of radial growth determination by the drilling resistance measurement method was studied: geometrical parameters of the cutting part of a thin drill bit, deviation of the drilling direction from the specified one, impossibility of precise determination of the strictly radial drilling direction, wood flaws, as well as friction of the drill shank when the drilling depth increases. To increase the accuracy of the method of measuring drilling resistance in dendrochronological studies it is proposed to develop a method including the use of a special or newly developed tool for more accurate determination of the core and radial drilling of wood or round timber; to increase the rigidity of the thin drill bit; to provide the required fixation of the thin drill bit during its initial contact with wood and inside the device. Further studies in this direction will be associated with the assessment of measuring accuracy for the radial growth of coniferous wood by the feeding force for drill bit penetration. For citation: Chernov V.Yu., Sharapov E.S., Gaisin I.G. Evaluation of the Accuracy of Wood Drilling Resistance Measurement Method in Dendrochronological Studies. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 5, pp. 135–150. (In Russ.). https://doi.org/10.37482/0536-1036-2023-5-135-150

Correction to: Study on Different Kinds of Drill Bits and Their Usage in Hard-to-Drill Formations

Correction to: Study on Different Kinds of Drill Bits and Their Usage in Hard-to-Drill Formations

<i>i</i>-MSE: A Fine Structure Imaging for Surface and Its Inside of Solid Material with Micro Slurry-Jet Erosion Test

We propose a fine structure imaging for the surface and its inside of solid material such as coated drill bits with TiN (Titanium Nitride). We call this method i-MSE (innovative MSE) since the fine structure is visualized with a local mechanical strength (the local erosion rate) which is obtained from a set of erosion depth profiles measured with Micro Slurry-jet Erosion test (MSE). The local erosion rate at any sampling point is estimated from the depth profile using a sliding window regression and for the rest of the 2-dimensional points it is interpolated with the mean value coordinate technique. The interpolated rate is converted to a 2D image (i-MSE image) with a color map. The i-MSE image can distinguish layers if the testing material surface is composed of coats which have different resistance to erosion (erosive wear), while microscopic image such as SEM (Scanning Electron Microscope) and a calotest just provides appearance information, not physical characteristics. Experiments for some layered specimens show that i-MSE can be an effective tool to visualize the structure and to evaluate the mechanical characteristics for the surface and the inside of solid material.

The effect of friction spot stir welding in double rivet lap joint installation of aluminum 2024-T3 on the strength of shear tests

The process of joining materials is very necessary to facilitate the manufacture of industrial products. Among these connections are rivets, bolts, nails, glue, and welding which is mostly done on metal materials. The aircraft skin is usually connected with rivets through a drilling process. Joining metal materials, especially aluminum, uses many welding techniques. The welding method currently being developed is Friction Stir Welding (FSW). FSW developed the Friction Stir Spot Welding (FSSW) process in joining metals, especially in this study using 2024-T3 aluminum. The purpose of combining the rivet method with FSSW is to see the material’s mechanical characteristics when applied to aluminum material. The FSSW method uses a 2500 RPM engine speed milling machine using a blunt tool holder with a pin dimension of 2.5 mm. It is carried out using a pneumatic drill using a drill bit with a dimension of 2.5 mm. Aluminum 2024-T3 has of 200×20×2 mm dimensions, a hole spacing of 15 mm with double rivet lap joint installation. The results showed that the FSSW variation had a higher tensile shear strength of 2.8% than the drilling variation. However, the hardness value in the drilling variation is 56.3% higher than the FSSW variation in the Heat Affected Zone (HAZ). Microstructural observations also indicate differences in the HAZ region, where the FSSW is reduced in size and longer. This is due to the heat treatment process due to friction between the pin tool and the aluminum, thus changing the structure.

Attitude Control of Rotary Steering Drilling Stabilized Platform Based on Improved Deep Deterministic Policy Gradient

Summary The rotary steerable drilling system is an advanced drilling technology, with stabilized platform toolface attitude control being a critical component. Due to a multitude of downhole interference factors, coupled with nonlinearities and uncertainties, challenges arise in model establishment and attitude control. Furthermore, considering that stabilized platform toolface attitude determines the drilling direction of the entire drill bit, the effectiveness of toolface attitude control will directly impact the precision and success of drilling tool guidance. In this paper, a mathematical model and a friction model of the stabilized platform are established, and an improved deep deterministic policy gradient (I_DDPG) attitude control method is proposed to address the friction nonlinearity problem existing in the rotary steering drilling stabilized platform. A prioritized experience replay based on temporal difference (TD) error and policy gradient is introduced to improve sample usage, and high similarity samples are pruned to prevent overfitting. Furthermore, SumTree structure is adopted to sort samples for reducing computational effort, and a double critic network is used to alleviate the overestimated value. Numerical simulation results illustrate that the stabilized platform attitude control system based on I_DDPG can achieve high control accuracy with both strong anti-interference capability and good robustness.

Development and Optimization of a High-Frequency Axial-Torsional Composite Percussion Drilling Tool for Enhanced Impact Technology

Summary A high-frequency axial-torsional composite percussion drilling tool is designed to enhance the drilling efficiency by delivering high-frequency axial and torsional impact loads directly to the drill bit. The impact performance and influencing factors of the tool are analyzed via the large eddy simulation method, and a scaled-down experiment on the pulse nozzle structure is conducted. The analysis reveals that after design optimization, the tool achieves high-frequency axial and torsional impacts of 421 and 284 Hz, respectively, at an inlet flow rate of 30 kg/s. Additionally, the unilateral amplitudes of the axial and torsional impact loads reach 1511 N and 19.3 N·m, respectively, with a pressure drop of 2.998 MPa. Furthermore, the similarity degree between the parameters derived from the experiment and numerical analysis is close to or exceeds 70%, demonstrating the reliability and precision of the numerical analysis results. Overall, this study sets a baseline for high-frequency impact technology, paving the way for further advancements in drilling efficiency.