Drilling Research Articles

Preliminary study on friction stir spot welding of plastic sheets with non-metallic tools

In recent years, 3D printing technology of engineering plastics is often used in various fields to develop prototypes of parts. Friction stir spot welding of lap joints of different engineering plastics has considerable potential for industrial applications. This study used a self-developed non-metallic tool to successfully form the PLA joints on a modified conventional drilling machine. The results show the average downward force and average welding torque decreased with increasing the rotating speeds and dwell times. The stir zone width is slightly increased with increasing the rotating speed, and its signification increased with the dwell time. The increase in stir zone width on the different rotating speeds and the dwell times is similar to the increasing trend in average temperature. The average temperature multiplied by the dwell time defined as the bonding factors is similar to the diffusion bonding. The stir zone width is increased with increasing the bonding factor because there has still some distance between the shoulder to the lap surface, the stir action by the shoulder is not easy riches to the lap surface, so the stir zone only occurs within the FSP zone and the stir zone width never exceeds the shoulder diameter.

Redesigning of Asella Animal Drawn Wheat Row Planter

This study was undertaken to redesign, fabricate, and evaluate the performance of animal-drawn seed drill prototype capable of drilling wheat and barley seeds and applying fertilizer at predetermined row spacing and depths. The physical properties of seeds involved in the study were investigated to optimize the design of the seed drill’s components. The developed seed drill machine, consists of a frame, seed and fertilizer hopper, seed metering devices, seed delivery tube, adjustable furrow opener, and drive wheels. The performances were evaluated in terms of Seed and fertilizer rate, row spacing, depth of seed placement, plant count/stand, field capacity and field efficiency. The investigation revealed that the sphericity of Hidase, Digelu, Ogolcho, and Kekeba wheat varieties were 65.81 %, 64.79% and 62.62 %, respectively. Row-to-row spacing can be 20 cm and depth also adjustable to 5 to 7 cm as per wheat agronomic requirements. The developed four row animal drawn seed drill was tested in the laboratory and field. The seed rate was calibrated and observed that 127 kg/ha with a middle flap position adjustment lying in the acceptable range of the recommended seed rate. There was no visible damage observed. The mean field capacity and field efficiency were 0.112 ha/hr and 81.78% at speed of 1.71km/hr. 310 to 318 plant populations per meter square (1 m2) area were observed during field germination count. Based on the performance evaluation results, it is concluded that the developed seed drill can be effectively and economically used by most farmers.

Toughening mechanism and delayed fracture analysis of 4145H steel under intercritical quenching heat treatment process

Tuning thermal treatment schedule has been confirmed as an effective technical route for achieving optimum properties of steels. In the present work, the intercritical quenching tempering(IQT) process was applied to steel 4145H for oil drilling tools, and the performance enhancement and delayed fracture mechanism of the IQT process were comprehensively elucidated using multiscale characterization methods and various mechanical tests. Compared with the quenching and tempering(QT), the IQT process results in a separate island ferrite plus finely tempered sostenite organization, which reduces the dislocation density in the tempered organization and increases the proportion of recrystallized grains. Due to the grain refinement effect of multiple quenching, the pristine austenite grains were refined by 58 %. At the same time, the proportion of large-angle grain boundaries increased from 68.6 % to 80.3 %. The results of the mechanical property tests show that the intercritical 790 °C quenching treatment and tempering at 600 °C exhibits a tensile strength of 1087 MPa, a high elongation of 21.72 %, and a high impact work of 104 J compared to QT. The improved impact toughness is mainly attributed to the grain refinement effect of multiple quenching and the large-angle grain boundaries provided by the composite ferrite organization and M23C6 carbides. The impact of different ratios of large-angle grain boundaries on crack extension was also evolved by means of the crystal phase field, and the delayed fracture effect of large-angle grain boundaries was verified.

Application and research of titanium alloy oil drill pipes

The complex and harsh drilling environment has put forward higher requirements and standards for future drilling tools. Compared with other drill pipes, titanium alloy drill pipe has a series of characteristics such as high specific strength, excellent corrosion resistance, fatigue resistance, and non-magnetic, making it be the first choice of material for oil and gas drilling in unconventional deep well, deep sea and other harsh environments. This paper discussed the design and microstructure properties of titanium alloy drill pipes in terms of alloy composition, service performance as well as pipe body processing and joint connection. Combined with the development of the application and standards of titanium alloy drill pipe, the prospects of the development and application of titanium alloy drill pipe in unconventional drilling operations such as deep wells and ultra-deep wells were foreseen, in order to provide support for promoting the application and development of titanium alloy drill pipe in the oil fields.

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.

Impact Characteristics of a Bidirectional Pneumatic DTH Hammer for Unconsolidated Formations

With advantages of high efficiency and low cost, DTH hammer drilling has been highly applied in various drilling projects. When drilling in unconsolidated formations, it is prone to drilling accidents such as drilling tools sticking or burying. Thus, a bidirectional pneumatic DTH hammer is designed to drill boreholes using forward impact and release sticking drilling tools using backward impact. With a floating gas distribution mechanism, impact strokes of the DTH hammer piston can be changed when flat keys are in a different position of the key grooves on the gas distribution shaft. In drilling mode, the piston has a larger impact stroke and can impact the anvil at high speeds to drive the bit breaking rocks. When drilling tools become stuck, by changing to a smaller impact stroke, the piston can impact backward on the gas distribution valve to break rocks above the DTH hammer so sticking drilling tools can be released. According to the structure and working principle of the bidirectional pneumatic DTH hammer, a physical model based on the pneumatic transmission circuit is established; then, a simulation model is built with pneumatic transmission module components in software of SimulationX 4.1 student version. Piston velocities, displacements, and impact energy are analyzed, with main factors including piston mass, total weight of the DTH hammer, compressed air pressure, and backward impact stroke being considered. Analysis results show that working characteristics of the DTH hammer are fairly affected by piston mass and compressed air pressure. Based on the changing laws of the impact frequency, peak of impact velocity, and impact energy, a piston mass of 18 kg, total weight of 125 kg, gas source pressure of 2.2 MPa, and lifting distance of 60 mm for backward impact were recommended. To verify the performance of the bidirectional pneumatic DTH hammer, field experiments were carried out in the gravel stratums. The bidirectional DTH hammer was in good working condition and the maximum drilling rate can reach up to 1.5 m/min. By lifting the DTH hammer away from the bottom of the borehole and pumping compressed air, the DTH hammer piston could achieve a high frequency backward impact. There are no drilling tools’ sticking or burying accidents in the drilling experiments. The bidirectional pneumatic DTH hammer can effectively drill boreholes in loose formations and deal with drilling tools’ sticking or burying accidents.

A novel Hybrid XGBoost Methodology in Predicting Penetration Rate of Rotary Based on Rock-Mass and Material Properties

Predicting the drill penetration rate is a fundamental requirement in mining operations, profoundly impacting both the cost-effectiveness of mining activities and strategic mine planning. Given the intricate web of factors influencing rotary drilling performance, the necessity for advanced modeling techniques becomes evident. To this end, the hybrid extreme gradient boosting (XGBoost) was utilized to gauge the penetration rate of rotary drilling machines, utilizing random search, grid search, Harris Hawk optimization (HHO), and the dragonfly algorithm (DA) as metaheuristic algorithms. Our research draws from extensive data collected in copper mine case studies, encompassing both field and investigational data. This dataset incorporates critical material properties, such as tensile strength (TS), uniaxial compressive strength (UCS), as well as vital rock-mass characteristics including joint direction (JD), joint spacing (JS), and bit diameter (D). Our investigation evaluates the reliability of these prediction methods using various performance indicators, including mean absolute error (MAE), root mean square error (RMSE), average absolute relative error (AARE), and coefficient of determination (R2). The multivariate analysis reveals that the HHO-XGB model stands out, demonstrating superior prediction accuracy (MAE: 0.457; RMSE: 2.19; AARE: 2.29; R2: 0.993) compared to alternative models. Furthermore, our sensitivity analysis emphasizes the substantial impact of uniaxial compressive strength and tensile strength on the drill penetration rate. This underlines the importance of considering these material properties in mining operations. In conclusion, our research offers robust models for forecasting the penetration rate of similar rock formations, providing invaluable insights that can significantly enhance mining operations and planning processes.

Coring tools have an effect on lithification and physical properties of marine carbonate sediments

Abstract. The International Ocean Discovery Program (IODP) JOIDES Resolution Science Operator typically uses an advanced piston corer (APC) in soft ooze and sediments and an extended core barrel (XCB) in firm sediments. The coring tool exchange typically occurs around the same depth in adjacent holes of the same site. However, during IODP Expedition 356, the coring tool switch occurred at different depths: IODP Sites U1463 and U1464 are marked by a stratigraphic interval (> 25 m thick) that was XCB cored in one hole and APC cored in other holes. Shipboard scientists remarked that APC-cored sediments were unlithified or partially lithified, while XCB-cored sediments were fully lithified. This difference in sedimentological description of the same formation seems to be an effect of coring technique. To provide further insight, we assessed the physical properties (bulk density, porosity, and P-wave velocity), downhole wireline logging data, scanning electron microscope (SEM) images, and micro-computed tomography (µCT) scans of those intervals. We find systematic differences between the different coring techniques. XCB cores are characterized by systematically lower bulk density, higher porosity, and higher P-wave velocity than APC cores. Downhole logging data suggest that the original P-wave velocity of the formation is better preserved in XCB cores, despite the typical “biscuit-and-gravy” core disturbance (i.e. well-preserved core fragments surrounded by squelched core material). In conjunction with SEM and µCT images, we conclude that the APC tool destroyed early lithification by breaking cements between individual grains. Moreover, µCT images reveal denser packing and smaller pore volumes in the APC cores. These sedimentary changes likely occur when the APC pressure wave passes through the sediment. The destruction of grain-to-grain cements provides an explanation for the significantly lower P-wave velocities in APC cores. Interestingly, the gravy sections in XCB drilled cores mimic the destruction of early lithification and reduction of pore volume. We conclude that APC remains the tool of choice for recovering soft sediments, especially for paleoclimate purposes. However, for the study of lithification, XCB biscuits provide a more representative image of the formation. For the study of early diagenesis, further studies are required to ascertain the preservation of key sedimentary features using existing and new drilling tools.

On-Farm Evaluation of Tractor Drawn Wheat Seed Drill

This experiment was conducted to evaluate the performance of a tractor-drawn wheat seed drill machine which can sow wheat and fertilizer at predetermined depths and row spacing. The machine performances were evaluated in terms of Seed and fertilizer rate, depth of seed placement, row spacing, plant population, field capacity, and field efficiency. Randomized complete block design with three forward speeds, three hopper loading, and three replications were used as experimental design. There were no visible or internal seeds damaged by the machine and it shows that there was no reduction in germination percentage when compared with the seed supplier recommendation. The seed and fertilizer rate was calibrated and recorded as 125 kg/ha and 150 kg/ha respectively for 20 cm row spacing. The seed drill was evaluated at speeds of 3, 4, 5 km/hr and hopper loading levels of H50, H75, and H100. Both the operating speed and hopper loading capacity of the machine had a significant effect on seed and fertilizer rate at p < 0.05. The average field capacity, field efficiency, and fuel consumption at 4km/hr speed of operation were 0.43 ha/hr, 85.93%, and 3.8 l/hr respectively. 378 to 380 plant populations per 1.2 m2 area were counted during seedling count. Depending on the results of the performance evaluation, it is concluded that the developed seed drill machine can be efficiently and economically used by the majority of farmers.

Real-time temperature prediction of lunar regolith drilling based on ATT-Bi-LSTM network

Lunar drilling is conducted in extreme environments, where limited heat dissipation pathways may cause overheating during drilling, potentially leading to destructive effects on the drill tool. To address the challenge of rapid temperature change in lunar regolith drilling, this paper presents a spatiotemporal feature fusion method for the real-time prediction of drilling temperature inside a lunar regolith simulant. The method aims to accurately predict the temperature of eight positions on the drill tool in the next second based on seven state parameters during drilling from the previous 20 seconds. It utilizes deep learning techniques to combine the Bi-LSTM and self-attention mechanism to fully exploit past and future information to extract spatiotemporal features from time series data and focus on the crucial features for temperature prediction. Additionally, a proposed early stopping-Bayesian hyperparameter optimization method is incorporated to effectively adjust the hyperparameters of the model. Experimental results demonstrate the superior performance of this method on data from drilling experiments with lunar regolith simulant in a vacuum chamber, significantly outperforming other models in statistical terms and meeting real-time prediction requirements. Furthermore, it exhibits robustness and generalization capability in practical applications on two different robotic drills. This research provides reliable support for predicting drilling temperature in future lunar exploration missions and reveals the spatiotemporal relationship in the thermophysical field during drilling. It holds crucial significance in guiding mission planners and operators to proactively implement appropriate measures in advance, ensuring the smooth operation of the drilling apparatus and comprehending the generation, conduction, and dissipation mechanisms of heat during lunar regolith drilling.

Experimental evaluation of corrosion inhibitors for completion fluids in the petroleum production systems

Corrosion is the natural and continuous degradation of materials caused by either chemical, mechanical, or electrochemical reactions. Corrosion inhibitors may be added to the completion fluids to address corrosion problems efficiently. It is critical to add corrosion inhibitors in completion fluids, specifically under high-temperature conditions, since the corrosion rate is higher when the temperature is high. This corrosion process limits the life of the drill tools or the oil and gas well and causes formation damage. This research studied corrosion and corrosion inhibition treatments for five completion fluids, namely potassium chloride, sodium chloride, sodium bromide, calcium chloride, and calcium bromide. Phosphate and sulfite-based corrosion inhibitors were individually added to the completion fluids, and their corrosion properties were studied to tackle the corrosion issue. In addition, a mixture of phosphate-based and sulfite-based corrosion inhibitors in completion fluids was studied. Additionally, the experimental results recommend using divalent brines as they were identified as a better medium for lowering corrosion rate and conditions than the monovalent brines. A novel aspect of this study is that the materials leveraged for conducting experiments are also used in actual petroleum production field operations. The experiments demonstrate that the corrosion rate can be efficiently controlled at high temperatures in deeper wells.

Cobalt-removed PDC as the diamond thrust bearing friction pair material: tribological behavior in water-based drilling fluids

To solve the problems of high vibration, low lifespan, and frequent replacement of diamond thrust bearings, the tribological behavior and friction mechanism of cobalt-removed and untreated PDC under different axial loads and rotational speeds were investigated in the WBDFs. The results indicated that the cobalt-removed PDC had lower friction coefficients, smoother friction status, better wettability, and better wear resistance than the untreated PDC. Cobalt-removed PDC could avoid the occurrence of thermal wear in the friction process, and the main forms of surface abrasion were dominated by mechanical wear. This study provides the experimental basis for the use of cobalt-removed PDC as a friction pair material for diamond thrust bearings, which can promote further research and development of downhole drilling tools.

Justification of drilling parameters of a typical well in the conditions of the Samskoye field

In the Republic of Kazakhstan, there is a noticeable shortage of water resources, which is a consequence of the natural features of its territory and climate. In particular, there are big problems in the water supply to the Mangystau region. The main source of water in the region is the Samskoye groundwater field. In this work, the conditions of the Samskoye field are typified, the method and technological parameters for drilling a typical well are selected and substantiated. It has been established that rotary drilling with reverse circulation in the conditions of the Samskoye field has significant advantages. The maximum possible production rate of drilling with reverse circulation, taking into account the limited thickness of the aquifer, is 4.3 times higher than with rotary drilling with direct circulation and 2.5 times higher than with percussion drilling. With the same filter pipe diameter, the greatest possible thickness of the gravel pack layer in reverse circulation drilling is 15 times greater than for conventional rotary drilling and 3.7 times greater than for percussion drilling. Thus, the use of rotary drilling with reverse circulation will solve an important problem – the provision of domestic and drinking water supply to the area.

Wear evaluation of palm oil and SAE 15W 40 engine lubricants with a ball-on-disk tester based on an improvised drilling machine

This paper introduces a modified ball-on-disk test, utilizing a drilling machine, to investigate the tribological behavior of wear on a plate surface under various lubrication conditions. The tribometer, based on the ball-on-disc principle, employs an improvised bench-top drill press machine. Despite its simplicity, it effectively facilitates wear-track experiments using engine oil (SAE 15W 40) and palm oil as lubricants. Tests are conducted at room temperature, maintaining a constant load at 8.83 N and rotational speed of 180 rpm for 2 minutes per sample. Microscopic analysis of wear scars on the plate samples reveals distinct wear patterns and characteristics for each lubricant, with measurements taken at multiple positions for accuracy. The current work focuses exclusively on wear scar analysis, with findings indicating that engine oil outperforms the counterpart, displaying a smaller wear track width, hence superior lubrication and wear protection capabilities. In contrast, palm oil exhibits a larger wear track, implying limitations in friction reduction and material preservation. This work has demonstrated the practical use of the cost-effective tribometer device for conducting preliminary studies of lubricant wear reduction performance. The test outcomes render valuable insights for lubricant formulators, particularly at the early stage of laboratory-scale development.

Effect Analysis of Demagnetization of Permanent Magnet Synchronous Motor for Electric Drilling Tool on Air-gap Flux Density

Electric drilling tools have been developed in the field of drilling because of their high efficiency. As the core component of electric drilling tool, permanent magnet synchronous motor(PMSM) provides power for drilling tool. However, in the process of drilling, the permanent magnet of PMSM will appear demagnetization.The value of air-gap flux density affects the performance and efficiency of the motor directly. Demagnetization faults are divided into uniform demagnetization and local demagnetization.In order to study the influence of demagnetization of PMSM on the air-gap flux density, mechanism of permanent magnet is analyzed Firstly, and then establishing numerical model with analytical method. Finally, simulation motor demagnetization using finite element method(FEM) based on Maxwell. No-load and load operating state are analyzed under the two fault modes are considered in this paper, and compared with the healthy state of the motor. The analytical results show that when the demagnetization fault occurs in the motor permanent magnet, the air-gap flux density will decrease accordingly.The FEM method results show that with the increase of uniform demagnetization rate, the flux density of the air-gap almost decreases in proportion to the increase of demagnetization rate. The demagnetization of single pole permanent magnet has little effect on the magnetic density of the nearby permanent magnet, but it will lead to the imbalance of the whole electromagnetic field of the motor. The air-gap flux density can be used as a characteristic index to judge the fault of demagnetization.

Electrodeposition of Double Chromium Plating to Improve Corrosion Performance of Screw Drilling in Chloride Environment

To adapt to and satisfy rising energy demand, oil and gas exploration and production are gradually spreading to locations with poor underground conditions, and the demand for screw drilling instruments is rising as well. When underground drilling tool materials are subjected to these harsh operating circumstances, they corrode severely and may even cause drill pipe breakage and blowout incidents. Failure due to corrosion is still the most common type of failure, with drilling fluid being the leading cause of downhole drilling tool corrosion and equipment damage, particularly in high-temperature and high-pressure working conditions with higher corrosiveness, which must be avoided and controlled. Double chromium was successfully plated on the surface of the screw rotor using the electrodeposition method to extend the service life of screw drilling instruments. Electrochemical methods such as scanning electron microscopy, open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization curve were used to analyze the plating’s morphology and corrosion resistance. The research results show that at high chloride concentrations (50g/L∼100g/L), when the chloride ion concentration is 60g/L, corrosion resistance is the lowest, and that double chromium plating enhances threaded drilling tool corrosion resistance. The dual chromium plating’s polarization resistance has been enhanced by 18 times. The double chrome plated milky white chrome plating functions as a physical barrier to prevent corrosive substances from diffusing to the substrate interface, corrosive ions from reaching the substrate, and considerably improving the screw rotor’s anti pitting performance.

Przegląd podstawowych równań oceny wydajności wiercenia

The main goal of the reviewed article is to provide statistically determined relationships between the parameters of disintegration processes and the properties of rocks. The results of theoretical and experimental studies are discussed and analysed in the article. In relation to drilling, the formulas of drilling speed, depending on various parameters as an indicator that fully reflects the efficiency of the process, are given and compared. Thus, the drilling speed for percussion drilling is related to the characteristics of the rock and, at the same time, taking into account the constructional characteristics of the drilling tool. In percussion drilling, a new formula for drilling speed is presented, considering each impact and the frequency of the impact. The expression for the drilling speed was determined taking into account the degree of crushing of the rock matrix during drilling. Thus, the drilling speed is determined by considering the contact strength of the rock being drilled in the mechanical drilling method. The distribution of the stress state in the drilling zone was determined. Also, the shape and development characteristics of the cracks formed in the rock during the operation of the drilling tool (especially the dynamic percussions of the tool in the bottom zone of the well) were investigated. It should be noted that the energy intensity of the drilling process in the rock was determined by studying the next stages of the process of breaking the rock. The technical and economic indicators of the drilling works have been evaluated. Corresponding mathematical formulas are presented as a reliable calculation of drilling rates. The relevant mechanical and geophysical properties of the excavated rocks were considered. In the article, the drilling tools are selected depending on the drilling method, physical-mechanical properties of the rocks and geological conditions of the rock mass. The results of the obtained studies can be used in the design of the technological parameters of the drilling. The observations and results expressed in the article have a theoretical and practical aspect.

PENGENALAN DAN PELATIHAN PENGAMBILAN SAMPEL TANAH DISTURBED DAN UNDISTURBED UNTUK SISWA SMK 7 BIDANG KEAHLIAN KONSTRUKSI JALAN, IRIGASI, DAN JEMBATAN

<p>One of the challenges faced by students from SMK is the learning atmosphere and learning system applied by PTV. This is due to the gap between the SMK curriculum and PTV. State Vocational High School (SMKN) 7 Semarang is one of the vocational schools located in the city of Semarang. SMKN 7 Semarang has 8 expertise competencies, one of which is competence in the field of civil engineering, namely Building Construction, Sanitation and Maintenance (KGSP) and Road, Irrigation, and Bridge Construction (KJIJ). Students of SMKN 7 Semarang already have a basic understanding of civil engineering, but when they enter the PTV world, they still experience difficulties in several fields. Therefore, to bridge and fill the gap from the SMK curriculum to PTV, it is necessary to introduce and train related fields of civil engineering, one of which is field testing. Semarang State Polytechnic as one of the universities has competent human resources to provide solutions to these problems. The PKM team provided introduction and training on the use of hand drill and vane shear tools used for soil testing. The hand drill is used to take disturbed and undisturbed soil samples, while the shear vane is used to determine the shear condition of the soil. After conducting the introduction and training activities, students can better understand how to use the test equipment. In addition, students also understand better in analyzing soil data obtained from testing.</p>

Influence mechanism of polycrystalline diamond compact bit temperature rise based on thermo-fluid-solid coupling.

In order to improve the drilling performance of polycrystalline diamond compact bit and prolong its service life during drilling in coal rock under the action of wind cycle, the theoretical calculation model of polycrystalline diamond compact bit cutting teeth temperature was derived based on the theory of tribology and heat transfer. The theoretical temperature field of polycrystalline diamond compact bit-cutting teeth was analyzed. Using the joint simulation of EDEM-FLUENT, the temperature variation law of polycrystalline diamond compact bit cutting teeth under the thermo-fluid-solid coupling was analyzed to verify the validity of the theoretical calculation model of polycrystalline diamond compact bit cutting teeth temperature. By building a rotary drilling test platform and conducting drilling experiments on polycrystalline diamond compact bit under different drilling parameters respectively, the correctness of the theoretical model and the simulation data were verified. In addition, a response surface analysis model was established to study the influence of different drilling parameters on the polycrystalline diamond compact bit cutting teeth temperature during drilling in coal rock. The analysis results show that the influence degree of various drilling parameters on the polycrystalline diamond compact bit cutting teeth temperature from large to small is drilling pressure, drilling speed, coal rock properties, and wind speed. Compared with the working condition without wind cycle, the drilling efficiency of polycrystalline diamond compact bit can be increased by 14.38% and the temperature is reduced by 8% when it drills in coal. The drilling efficiency of polycrystalline diamond compact bit can be increased by 17.79% and the temperature is reduced by 10.5% when it drills in coal gangue.