Optimization Of Drilling Parameters Research Articles

Improvement of the Hammer Drill Performance (Algerian Quarries Conditions)

Abstract The factors which influence the performance characteristics of a hammer drill are examined; drilling data are analyzed to determine these factors. Methods for selecting the appropriate drilling are also highlighted. Two models are used in order to compare optimal drilling parameters. The main one is the machine output.

Drill Hole Orientation: Its Role and Importance on the Compression Response of Pure Magnesium

Drilling is used in creating cylindrical through-holes for various applications. While optimizing drilling parameters is widespread, the effect of a drilled through-hole on the structural stability of components is not fully documented. The base material, along with other parameters, such as drill diameter, drill location and its orientation affect structural stability. Since carrying out tests on different base materials can be time consuming, simulation software can instead be used to provide valuable information. However, the comparison between experiments and simulations gets difficult; hence, this study attempts to provide a basis for effective comparison by studying simulations and compression tests, comparing the two, and documenting the role of drill hole orientation on the compressive response of magnesium, a material with immense potential in light-weight components. Simulations and experiments were carried out on three through-hole orientations and were compared to the undrilled scenario. Results demonstrate significant differences in compression behaviour. While the compressive yield strength increased in all three drill orientations, ultimate strength and ductility was reduced in horizontal and angular drill hole orientations. These observations, therefore, provide valuable insight into choosing the right orientation for different applications.

Evaluation methods and standards for rock drillability in oil and gas drilling engineering in China: A review

In western China, 70% of the oil, gas, and geothermal resources are buried in deep formations (more than 3000 m), but the low rate of penetration has become a key factor restricting the development of these resources. Rock drillability evaluation is a basic task for oil, gas, and geothermal drilling engineering design that includes bit design, bit selection, and drilling parameter optimization. Different tests and standards to evaluate rock drillability have been developed worldwide. Against this backdrop, the evaluation methods and standards for rock drillability are reviewed. Various rock drillability tests and classification standards are compared and analyzed. Results show that these methods and standards are inaccurate and fail to meet the design requirements of drilling technology and bit selection in deep and ultradeep drilling wells. In China, micro-drilling test is commonly used to evaluate rock drillability in oil and gas drilling engineering. This method was developed as an oil and gas industry standard and has been used for more than 40 years. However, its results do not reflect the significant effects of high temperature and pressure at the bottom hole on rock drillability and breaking; thus, the results cannot be used in drilling designs. Testing methods and classification standards for rock drillability require innovative developments. This review highlights the following: (1) the classification standards for rock drillability must be refined in the future to meet the requirements of drilling designs in deep and ultradeep wells; (2) efficient and fast rock drillability tests are required to deal with complex and difficult formations; (3) the influence of the real physical environment of the borehole bottom on rock drillability must be further clarified.

A feasible strategy to produce quality holes using temperature-assisted drilling on CFRP

Drilling of carbon fibre–reinforced polymer composite (CFRP) material is an essential machining process in aerospace structural applications to fix/bolt holes for assembling parts. Here, producing quality holes is essential to avoid rejection of parts and it remains a great challenge to overcome damages while drilling. Monitoring the optimal drilling parameters and environmental conditions is a viable strategy to reduce the drilling-induced damages in CFRP. In this experimental investigation, a comparative study is made between chilled air–, dry air– and hot air–assisted drilling on UD-CFRP material, and the effect of drilling parameters is outlined. The thrust force, delamination, burr formation, surface roughness and surface damages of the drilled hole are analysed at different environments and machining conditions. The experimental results indicated that the drilling at the hot air environmental condition reduces the thrust force and delamination factor at low feed rate. At the same time, a higher burr removal rate and increased surface finish were obtained at the chilled air condition when compared with other environmental conditions.

Optimized selection of process parameters based on reasonable control of axial force and hole-exit temperature in drilling of CFRP

Drilling is a key link of manufacturing carbon fiber-reinforced polymer (CFRP) components. However, due to CFRP’s anisotropy and heterogeneity, effects of drilling induced axial force and hole-exit temperature are much more complicated than conventional metals, which always results in undesirable surface damages at hole exit hindering the engineering application of CFRP. Since the axial force and the hole-exit temperature are highly correlated to process parameters in drilling of CFRP, for effectively overcoming such difficulties, this study focuses on optimized selection of process parameters. The suitable ranges of the axial force and the hole-exit temperature are figured out, upon the specific analysis on the combined effects of the axial force and the hole-exit temperature on the formation of hole-exit surface damages. With that, through establishing the relations between the axial force, the hole-exit temperature, and the drilling parameters, the optimized drilling parameters are finally given. By experimental verifications, it is found that the optimized drilling parameters can control the axial force and the hole-exit temperature within the suitable ranges, and thereby effectively suppress the hole-exit surface damages in drilling of CFRP. The findings of this study will be helpful to further improve the drilling qualities of CFRP.

Effects of cutting temperature and process optimization in drilling of GFRP composites

The present work deals with temperature effects and parametric optimization in the drilling of continuous glass fiber reinforced epoxy composite. Drilling ability was examined operating a drilling system with different drill bits, feed rate, and spindle speed parameters. The investigation was performed by changing the tool and composite interface. Drilling experiments were carried out under the dry condition. Thrust force and drilling temperatures were measured using dynamometer and thermal camera. Peel-up and push-out delamination were evaluated using an image analyzing tool. Results show that the tribo-mechanical behavior of the drilling operation is affected at different levels by tool coating. This behavior is related to the intrinsic friction properties of coating nature. Response surface methodology was used in the evaluation of experiment results. The feed rate of 0.13 mm/rev, spindle speed of 2425 rpm and HSS-TiN drill bit are found as an optimum drilling parameters and drill type.

Experimental Research on Rotation-Percussion Drilling of Diamond Bit Based on Stress Wave

Rotary-percussive drilling is a common form of drilling in geotechnical engineering. in order to study the effect of rotational speed and impact speed on rock-breaking efficiency, a drilling simulation platform developed by ourselves and a drill pipe equipped with diamond bit were used to conduct simulated drilling experiments. By monitoring the stress wave during drilling, the strain, stress and energy changes at different rotational speeds and impact velocities can be obtained, and the optimal drilling parameters can be determined. The results show that both speed and impact velocity have direct influence on the drilling process. When the rotational speed is kept constant, the drilling efficiency increases first and then decreases with the increase of the impact velocity. When the impact velocity remains constant, the drilling efficiency decreases with the increase of rotating speed. With the increase of rotational speed, the optimal impact velocity also increases. It is helpful to improve the drilling efficiency by reasonable choice of speed and impact speed.

Investigation of the effects of ultrasonic assisted drilling on tool wear and optimization of drilling parameters

In this study, ultrasonic-assisted drilling was performed on different heat-treated (T6, T1) AA6061 to investigate the effects of cutting parameters on forces, surface roughness, and tool wear. TiN-coated and uncoated HSS-G drill bits were used in the experiments. The results obtained in the experiments were evaluated according to the general full factorial design and the effect graphs of different drilling parameters were generated. In addition, ANOVA tables were created to evaluate the results. SEM and OM micrographs were used to investigate the tool wear and chip formation. Finally, a multi-response optimization was performed to optimize drilling parameters for minimum cutting force and surface roughness. According to, optimum drilling parameters were determined as AA6061-T6 for material, uncoated HSS-G for a drill bit, 1520rpm for spindle speed, and highest ultrasonic vibration frequency at 22.5kHz. In addition, it was observed that ultrasonic vibration has the effect of reducing built-up edge formation on the drill bit.

Optimization of modulation-assisted drilling of Ti-6Al-4V aerospace alloy via response surface method

ABSTRACT The study concerned with optimization of modulation-assisted drilling (MAD) operation for a difficult-to-cut material Ti6Al4 V was carried out via response surface method (RSM). Conventional drilling (CD) has been explored for comparison purposes. Experiments have been designed according to the Central Composite Design (CCD). The impact of machining input parameters on surface roughness (SR), machining power consumption, and tool wear (TW) was investigated for both cases. Pilot experiments were carried out to find out the best modulation range. Further drilling experiments were carried out varying feed rate, spindle speed, and tool diameter. Multiple regression analysis using RSM established relationships between these parameters and responses. ANOVA was used to develop and test the mathematical models. The models were effective in predicting the responses for MAD of Ti6Al4 V. The optimum drilling parameters are a tool diameter (TD) of 2 mm, feed rate (FR) of 0.030 mm/rev and spindle speed (SS) of 2176.87 rpm. SEM and EDS analyzes were performed to investigate the machined surfaces. From the study, it can be concluded that MAD is a promising machining process for difficult-to-cut materials with comparatively less thrust force, surface roughness and tool wear. Abbreviations SD Standard deviation; SS: Spindle Speed; TF: Thrust Force; BUE: Built-Up-Edge; PRESS: Prediction error sum of squares; TD: Tool Diameter; CD: Conventional Drilling; CV: Coefficient of variance; MAD: Modulation-Assisted Drilling; SR: Surface Roughness; VAM: Vibration-Assisted Machining; TW: Tool Wear; RSM: Response Surface Methodology; ANOVA: Analysis of Variance; FR: Feed Rate; SNR: Signal-to-Noise Ratio; FW: Flank wear

Study of High-Speed Mechanical Micro Drilling Process Fundamentals for Small Holes

High-speed mechanical micro drilling would be a promising process for small hole fabrications with high productivity and high quality. But there are limited studies on this topic. Fundamental questions such as the minimum undeformed chip thickness (MUCT) due to the size effect in microcutting, burr size, cutting force, and optimal parameters are discussed for high-speed mechanical micro drilling in this paper. Based on finite element method (FEM) modelling, the MUCT is identified as 0.86 μm for copper C26000 with the cutting edge radius of 5 μm from both chip generation and force variation analyses. The ratio of MUCT to the cutting edge radius is 0.17, which is smaller than that (usually 0.2 or 0.25 for copper) in micro shaping and micromilling processes. This result has been successfully verified by experiments with the drill with a diameter of 1 mm and the spindle speed of 80,000 min-1. Burr width at the hole entrance reaches the maximum value when the undeformed chip thickness (UCT) is smaller than the MUCT. Experimental optimizations with the integrated considerations of cutting forces and burrs have been conducted. The optimal high-speed micro drilling parameters have realized a material removal rate (MRR) of 25% increasement compared with conventional micro drilling.

Investigation of Machining Characteristics and Drilling Parameters Optimization in Drilling of Nimonic C-263 Alloy

This paper contains the investigation of machining characteristics and machining parameters optimization while drilling Nimonic C263 alloy. The proposed method is designed as per Taguchi’s Design and drilling trials are conducted utilizing ALCRONA coated drills. An empirical model has been proposed for process performance prediction via RSM (Response Surface Methodology). The optimization of multi response has also been carried out depends on function of desirability approach. The optimized cutting conditions were established. Confirmation tests were conducted to confirm the modelling results.

Study on horizontal wellbore flow of supercritical carbon dioxide drilling

The filter loss in the long open hole interval is considerable during horizontal well drilling utilizing SC-CO2, which affects the wellbore temperature and pressure distribution. In this study, a wellbore flow and heat transfer model that considers fluid filtration characteristics, viscous friction heat production and CO2 physical properties is developed. The temperature and pressure are coupled using an alternating direction iterative method and the flow behavior of SC-CO2 in a horizontal wellbore is analyzed in detail. The results indicate that the mass flow rate loss factor can reach 12.33% at a well depth of 5000 m, but the CO2 leak-off has little influence on wellbore temperature–pressure distribution. In addition, phase transition occurs both in the drill pipe and the annulus during CO2 circulation, and wellbore pressure–temperature conditions are highly related to CO2 physical properties. The operating parameters affect the whole wellbore pressure level; however, they have little effect on the temperature of horizontal interval. Furthermore, the annulus pressure level and the open hole length of horizontal interval are major factors affecting CO2 leak-off. The model can help set the optimum drilling parameters during the actual SC-CO2 drilling process to effectively promote the technology.

Optimization and Modeling of Process Parameters in Multi-Hole Simultaneous Drilling Using Taguchi Method and Fuzzy Logic Approach.

In industries such as aerospace and automotive, drilling many holes is commonly required to assemble different structures where machined holes need to comply with tight geometric tolerances. Multi-spindle drilling using a poly-drill head is an industrial hole-making approach that allows drilling several holes simultaneously. Optimizing process parameters also improves machining processes. This work focuses on the optimization of drilling parameters and two drilling processes—namely, one-shot drilling and multi-hole drilling—using the Taguchi method. Analysis of variance and regression analysis was implemented to indicate the significance of drilling parameters and their impact on the measured responses i.e., surface roughness and hole size. From the Taguchi optimization, optimal drilling parameters were found to occur at a low cutting speed and feed rate using a poly-drill head. Furthermore, a fuzzy logic approach was employed to predict the surface roughness and hole size. It was found that the fuzzy measured values were in good agreement with the experimental values; therefore, the developed models can be effectively used to predict the surface roughness and hole size in multi-hole drilling. Moreover, confirmation tests were performed to validate that the Taguchi optimized levels and fuzzy developed models effectively represent the surface roughness and hole size.

Optimal Simulation and Mathematical Correlation of Mud Weight for Effective Wellbore Stability Management

Wellbore instability is a problem that affects drilling activities. It is therefore important to provide an optimal solution that prevents or reduces the occurrence of wellbore collapse and not compromise the integrity of the well. In this study, work was done to assess the impact of several parameters including tubing pressure, tubing fluid temperature, length of tubing, gas density, liquid density, tubing hold-up and total mass flow on mass fraction of tubing muds were considered. Data points for this investigation were obtained using OLGA multiphase simulator. The results of the simulation (including the trend and plot data) were exported to MATLAB to develop a mud weight model (correlation) using the MATLAB regress function. The correlation was also validated using statistical techniques such as the R square and Significance F values. Comparison of the trend plots of the actual data points from OLGA and the predicted data points was also done to further prove the reliability of the correlation. The correlation predictions agreed with the OLGA results excellently with a relative error of less than 0.001 %. This study revealed that the tubing mud weight is significantly impacted on by variables like tubing holdup, tubing gas density, tubing liquid densities and the total mass flow. Whereas the tubing pressure, fluid temperature, and the tubing length have insignificant effects on the tubing mud weight. From the trend plots of the variables, it was deduced that as the tubing pressure increased, the temperature and the mud weight also increased. While, the total mass and volumetric flows reduced with increased tubing pressure. The effect of input data uncertainties on the developed correlation were also tested by using 22 observation points to predict tubing mud weight and calculating the resulting residual values. Over 90% of the residual values were negative and the percentage difference in mud weight between the first and the last observation points was approximately 4%. Hence, the effect of input data uncertainties on the developed correlation is insignificant. This report will serve as a template for drilling engineers, assisting them with a simple, fast and reliable technique for determining optimum drilling parameters with a lesser engineering exertion and drilling experience.

Optimal Simulation and Mathematical Correlation of Mud Weight for Effective Wellbore Stability Management

Wellbore instability is a problem that affects drilling activities. It is therefore important to provide an optimal solution that prevents or reduces the occurrence of wellbore collapse and not compromise the integrity of the well. In this study, work was done to assess the impact of several parameters including tubing pressure, tubing fluid temperature, length of tubing, gas density, liquid density, tubing hold-up and total mass flow on mass fraction of tubing muds were considered. Data points for this investigation were obtained using OLGA multiphase simulator. The results of the simulation (including the trend and plot data) were exported to MATLAB to develop a mud weight model (correlation) using the MATLAB regress function. The correlation was also validated using statistical techniques such as the R square and Significance F values. Comparison of the trend plots of the actual data points from OLGA and the predicted data points was also done to further prove the reliability of the correlation. The correlation predictions agreed with the OLGA results excellently with a relative error of less than 0.001 %. This study revealed that the tubing mud weight is significantly impacted on by variables like tubing holdup, tubing gas density, tubing liquid densities and the total mass flow. Whereas the tubing pressure, fluid temperature, and the tubing length have insignificant effects on the tubing mud weight. From the trend plots of the variables, it was deduced that as the tubing pressure increased, the temperature and the mud weight also increased. While, the total mass and volumetric flows reduced with increased tubing pressure. The effect of input data uncertainties on the developed correlation were also tested by using 22 observation points to predict tubing mud weight and calculating the resulting residual values. Over 90% of the residual values were negative and the percentage difference in mud weight between the first and the last observation points was approximately 4%. Hence, the effect of input data uncertainties on the developed correlation is insignificant. This report will serve as a template for drilling engineers, assisting them with a simple, fast and reliable technique for determining optimum drilling parameters with a lesser engineering exertion and drilling experience.

Nonlinear dynamics of lump mass model of drill-string in horizontal well

We develop a dynamic model of a drill-string in a horizontal well having six Degrees-Of-Freedom, which accounts for longitudinal, lateral and torsional motions. In this model, nonlinearities that arise due to intermittent contacts of a drill-pipe with a borehole wall and complex interactions between a drill-bit and a rock formation are all considered. The lateral motions of the drill-bit are restricted and its interactions with a borehole generate an interlaced force being result of a friction and a cutting that has a regenerative effect. In the cutting process, a state-dependent time delay is introduced to couple the axial and torsional motions of the drill-bit. The dynamic model established in this article is tested where the friction and cutting effects are gradually switched on, which shows that the model is robust. Subsequently, the complex whirling of a horizontal drill-string is analyzed and a particular attention is given to the influence of driving rotation speed and dynamic friction coefficient. The study should help us to better understand nonlinear dynamic effects of drill-strings in horizontal wells, which will lay a foundation for optimizing drilling parameters.

Taguchi Grey Relational Analysis based Optimization of Micro-Drilling Parameters on Carbon Fiber Reinforced Plastics

The paper presents the optimization of micro drilling parameters in the Carbon Fiber Reinforced Plastics (CFRP), using different drill bits of measurement 0.7mm, 0.8mm, and 0.9mm by the Taguchi Grey Relational analysis (TGRA). For the Micro drilling test, the process parameters chosen are spindle speed, feed rate and drill diameter. The experiments are designed by the Taguchi's L27 orthogonal array. The trials are directed to enhance the machining condition and at the same time minimize the delamination factor, tool wear rate and boost the material removal rate. The optimum values for the minimized delamination factor, maximized material removal rate and the minimized the tool wear rate are identified by the performing the Taguchi Grey Relation Analysis. ANOVA of the S/N ratio is also performed to identify the percentage contribution of the selected parameters.

Study of the influence of models on the drilling temperature of bone measured by thermocouples

Bone drilling is a standard procedure in medicine mainly for internal fixation with a gripper plate. Drilling bone generates much heat, then the heat causes the temperature of bone to rise, nearby the borehole rapidly, while drilling. Studies indicated that the bone would irreversibly be damaged after being heated up to 47°C for 60 s. Hence, it is vitally important to control the drilling temperature of bone. Two different models of the tibia for drilling simulation were established with ABAQUS software based on finite element analysis in this article. The first model is an approximate ideal model of the tibia with fluid in the bone cavity. And the other one is a tubular tibia without fluid in the bone cavity, and a pair of thermocouples is embedded to match the experimental condition when measuring the drilling temperature. The distribution of heat on the bone and the highest drilling temperature were revealed by simulation, and the influences of drilling parameters on drilling temperature of bone were also explored by variance analysis. The results show that the maximum drilling temperature increases with an increase in the diameter of bit and spindle speed. The drilling temperature also increases as the feed rate increase, but the effect of feed rate on drilling temperature is not as significant as that of spindle speed. The drilling temperatures of two models were obtained by the finite element method. The maximum temperature of model 1 is taken as the benchmark. The temperature of model 2 takes as the experimental result. A formula for modifying the experimental temperature to actual value was derived. Then predicted temperature of model 1 could be achieved to obtain the optimized drilling parameters.

Improved drifting oscillator model for dynamical bit-rock interaction in percussive drilling under high-temperature condition

High cost is the main factor restricting the development and utilization of geothermal resources, and the proportion of drilling costs is even higher than 50%. Therefore, it is crucial to find an efficient drilling method and optimize drilling parameters. Percussive drilling is a widely-recognized efficient geothermal drilling method. In this study, an improved drifting oscillator model is developed to determine the optimal drilling parameters by representing the dynamical interaction between drill bit and high-temperature granite (HT-G). The Abel damper is introduced to represent the nonlinear relationship between the damping force and strain rate. Solutions of HT-G Young's modulus and viscosity coefficient as a function of temperature are obtained by experimental data fitting. Then the rock response without and with bit penetration are studied theoretically and numerically, respectively. Finally, experiments are conducted to validate the effects of wave shapes and frequency of the impact load on rate of penetration (ROP). The results show that the ROP increases with the increase of temperature, which proves that percussive drilling is more suitable for HT-G formation than the conventional oil-gas reservoir. There is an optimal frequency ranging from 60 to 120 Hz where the system gives the best drilling performance when sin-shape impacts are applied. Rectangular-shape load gives the fastest ROP among the three evaluated wave shapes of excitation load, especially when the frequency is low. The research of this paper provides a basis for the application of percussive drilling in HT-G formation and is of great significance to the design of downhole impactor and formation adaptability evaluation.

Investigation on effect of process parameters on delamination during drilling of kenaf‐banana fiber reinforced in epoxy hybrid composite using Taguchi method

AbstractDelamination is a serious issue during drilling of FRP composites. The purpose of this research is to determine the effect of process parameters on delamination during drilling of kenaf and banana fiber reinforced in epoxy hybrid composite using Taguchi method. The FRP composite was fabricated by hand‐layup technique. The fabricated specimen was drilled using HSS drill bits (5, 10, 15 mm) coated with tungsten carbide. The contemplated process parameters are feed, and speed. The “Minitab 18” software was employed to investigate the data collected by taking advantage of the various statistical and graphical tools available. The trials were carried out by taking advantage of Taguchi's L‐9 factorial design orthogonal array. Through several steps, it was found that the optimum drilling parameters are spindle speed = 3000 rpm; feed = 150 mm/min. Thus, in this research, an attempt has been made to optimize the drilling parameters.