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The long and large diameter uncharged hole boring (LLB) method is a cut blasting method that minimizes blast-induced vibrations by creating long and large diameter uncharged holes at the excavation face of tunnels prior to tunnel excavation. Drilling in this method typically uses a 50 m long with a 382 mm diameter hammer bit in the horizontal direction at the tunnel face. However, the significant weight and uni-directional rotation of the rod head, as well as variables such as geological characteristics, machine conditions, and inexperienced operators result in significant deviation from the target borehole alignment that hinders the vibration-dampening effect of the uncharged holes. Furthermore, since there is no method to verify the alignment of the boreholes until main tunnel construction, borehole misalignment is often not discovered until weeks after construction, which requires tunnel construction to cease until the equipment can be remobilized and an additional borehole be created, causing significant delays and increased costs for the entire tunnel project. In this study, the borehole alignment tracking and ground exploration system (BGS) is developed to predict and monitor the quality and alignment of boreholes for cut blasting methods such as the LLB methods immediately after boring. The BGS was subsequently tested at a subway construction site to evaluate its performance in the field. The measurements yielded by the BGS were compared with manually measured boring positions at every 5 m along the borehole. Although the BGS showed a maximum deviation of approximately 12% at a local point where the hole surface was relatively rough, the accuracy for the final boring position was approximately 97%, demonstrating excellent precision of the alignment tracking system. The BGS demonstrates excellent performance in predicting ground conditions and the boring quality of a cut hole immediately after drilling, and shows promise in various other applications for monitoring borehole alignment. [ABSTRACT FROM AUTHOR]

The fact is that hundreds of holes are drilled in the assembly process of furniture sets, so intelligent drilling is a key element in maximizing efficiency. Increasing the feed rate or the cutting speed in materials characterized by a higher machinability index is necessary. Smart drilling, that is, the real-time adjustment of the cutting parameters, requires the evolution of cutting process variables. In addition, it is necessary to control and adjust the processing parameters in real time. Machinability is one of the most important technological properties in the machining process, enabling the determination of the material's susceptibility to machining. One of the machinability indicators is the unit cutting resistance. This article proposes a method of material identification using the short-time Fourier transform in order to automatically adjust cutting parameters during drilling based on force signals, cutting torque and acceleration signals. In the tests, four types of wood-based materials were used as the processed material: medium-density fiberboard, chipboard, plywood board and high-pressure laminate. Holes with a diameter of 10 mm were drilled in the test materials, with variable feed rate, cutting speed and thickness of cutting layer. An innovative method for determining the value of unit cutting resistance was proposed. The results obtained were used to determine the machinability index. Based on the test results, it was shown that both the selected signal measures in the time and frequency domains and the unit cutting resistance are constant for a given material of a workpiece and do not depend on the drilling process parameters. In this article, the methodology is proposed, which can be used as an intelligent technique to support the drilling process to detect the material being machined using data from sensors installed on the machine tool. The work proposes the fundamentals for material identification based on the analysis of force signals and the magnitude of force derivatives. The proposed methodology shows effectiveness, which proves that it can be used in intelligent drilling processes. Hybrid wood-based material structures consisting of different materials are becoming more and more common in building structures for strength, economic and environmental reasons. Due to the difference in the machinability of interconnected materials, cutting parameters must be optimized in real time during machining. Currently, with the rapid development of Industry 4.0, the on-line identification of parameters is becoming necessary to improve the process flow in industrial reality. The proposed methodology can be used as an intelligent technique to support the drilling process in order to detect the material being processed using data from sensors installed on the machine tool. [ABSTRACT FROM AUTHOR]

According to the convergence confinement theory, it is an effective measure to control the large deformation of high ground stress in fractured soft rock tunnels by using yielding support. The yielding support can be classified as either radial or circumferential yielding support. Circumferential yielding support is achieved by transforming radial displacement into circumferential tangential closure without compromising the support capacity of the primary lining support structure. Based on this, and inspired by the design principle of dampers, a yielding support structure system with spring damping elements as its core was developed, based on the connection characteristics of steel arches in highway tunnel, which can provide increasing support resistance in the yielding deformation section. Then the mechanical properties of spring damping elements were obtained through indoor axial pressure and flexural tests. In addition, according to these results with numerical calculations, the yielding support structure system with embedded spring damping elements can reduce the internal force of the support structure by approximately 10% and increase the area of the plastic zone of the surrounding rock by 11.23%, which can fully utilize the self-bearing capacity of surrounding rock and verify the effectiveness of circumferential yielding support. Finally, the spring damping support structure system was designed with reference to the construction process of the tunnel excavated by drilling and blasting method, and the transformation of the spring damping element to spring damping support structure was achieved. Based on field test results, surrounding ground pressure for the yielding support optimization scheme was reduced by 40% and more evenly distributed, resulting in the successful application and a reduction in the construction cost of large deformation tunnels in soft rock. [ABSTRACT FROM AUTHOR]

The penetration coefficient can represent the relationship between force and depth in the rock drilling process, but its understanding is limited. Therefore, based on the rock drilling theory with a hydraulic breaking hammer, a mathematical model of the penetration coefficient is established in this paper, and the main influencing factors of the penetration coefficient are determined. The discrete element method is used to establish a rock simulation model that can represent the real characteristics, and the variation law of the penetration coefficient under cyclic impact is studied. In addition, the drilling processes of drill bits with different impact velocities, shapes, and angles are simulated to evaluate the effects of operational parameters on the penetration coefficient. The results show that cyclic impact will change the rock cohesion and affect the change in the penetration coefficient. With an increase in impact times by the same drill bit, the penetration coefficient first increases and tends to be stable, and then decreases. Regarding operational parameters, the impact velocity has little effect on the penetration coefficient, while the shape and angle of the drill bit have a significant effect on the penetration coefficient, and a drill bit with a smaller angle is accompanied by more rock debris. Highlights: A theoretical model of the penetration coefficient is established. DEM simulation reveals the rock drilling mechanism under cyclic impact. The effect law and significance of operation parameters are obtained. [ABSTRACT FROM AUTHOR]

The collaborative robot can complete various drilling tasks in complex processing environments thanks to the high flexibility, small size and high load ratio. However, the inherent weaknesses of low rigidity and variable rigidity in robots bring detrimental effects to surface quality and drilling efficiency. Effective online monitoring of the drilling quality is critical to achieve high performance robotic drilling. To this end, an end-to-end drilling-state monitoring framework is developed in this paper, where the drilling quality can be monitored through online-measured vibration signals. To evaluate the drilling effect, a Canny operator-based edge detection method is used to quantify the inclination state of robotic drilling, which provides the data labeling information. Then, a robotic drilling inclination state monitoring model is constructed based on the Resnet network to classify the drilling inclination states. With the aid of the training dataset labeled by different inclination states and the end-to-end training process, the relationship between the inclination states and vibration signals can be established. Finally, the proposed method is verified by collaborative robotic drilling experiments with different workpiece materials. The results show that the proposed method can effectively recognize the drilling inclination state with high accuracy for different workpiece materials, which demonstrates the effectiveness and applicability of this method. [ABSTRACT FROM AUTHOR]

Rotary percussion rock drills have been widely used in mining and civil engineering fields, and their performance needs to be further improved. To deeply understand the mechanisms of the rock drills, this article reviews the previous studies from fundamental theories to state-of-the-art techniques on the rotary percussive rock drilling processes, including stress wave propagation, dynamic bit penetration, and factors affecting drilling efficiency and penetration rates. An enormous variety of research approaches and their findings are provided to related researchers and engineers. In addition, important future issues are presented for discussing the further progress of rotary percussive rock drilling. [ABSTRACT FROM AUTHOR]

The critical factors that affect bottomhole stick–slip vibrations during vertical drilling operations are thoroughly investigated and analyzed in this research. Influential factors, such as rotation speed, weight on bit (WOB), bottom hole assembly (BHA) configuration, and formation properties, were studied in order to understand their part in the stick–slip phenomena. The analysis is based on a thorough review of previous research conducted on stick–slip drilling vibrations. A mathematical model was created that not only explains axial vibrations but also includes the torsional vibrations present in stick–slip occurrences, which helps with understanding the stick–slip phenomena better. This model can be used as an analytical tool to predict and evaluate the behavior of drilling systems under various operational circumstances. Furthermore, two drilling tests using a WellScan simulator were performed to validate the research findings and assess mitigation techniques' viability. These test scenarios reflect the stick–slip vibration-producing situations, allowing us to test mitigation strategies. The finding of this study shows the effectiveness of two tactics for reducing stick–slip vibrations. First was the reduction of WOB, which successfully lowered the occurrence of stick–slip vibrations. The second was the increase in the rotation speed, which helped to control the stick–slip problem and increased the drilling speed. This study explains the complex dynamics of stick–slip vibrations during vertical drilling and offers practical, tried-and-true methods for reducing their adverse effects on drilling operations. [ABSTRACT FROM AUTHOR]

The mechanical parameters of a rock mass are the basis for studying the deformation and failure mechanisms and control methods of the surrounding rock in underground engineering. At present, these parameters are mainly obtained through laboratory tests of cores obtained from surrounding rock in the field. It is difficult to core the broken surrounding rock, and a rock core is detached from an environment with on-site stress. The rock mass drilling test can provide a new method to solve the above problems. This paper has developed a rotary cutting test system for rock mass (RCT system) for research on the relationships between drilling parameters and rock mechanics parameters. The basic characteristics and structure of the RCT system were introduced, digital drilling tests of different rock mass specimens were conducted for various control parameters and different bit types. The relationships between drilling parameters, and the response law of drilling parameters to rock mechanics parameters and drill bit structural parameters during rock drilling were systematically analyzed. The research lays a foundation of equipment and theory for implementing testing of rock mass parameters while drilling. [ABSTRACT FROM AUTHOR]

The Meso-Neoproterozoic is a new play in the Ordos Basin. A deeper understanding about the dynamic relationship between the caprocks and the source rocks is needed. Based on the comprehensive analysis of hydrocarbon source development characteristics of the Meso-Neoproterozoic and its overlying strata, as well as the formation contact relationships, lithology characteristics and exploratory drilling data, it is recognized that the Meso-Neoproterozoic contains two types of petroleum accumulation assemblage, that is, the "self-sourced indigenous" and "upper source rock-lower reservoir" assemblages. The former is mainly controlled by the development and distribution of source rocks of the Changcheng System, with the Lower Cambrian shale sequence as its caprock. The later is controlled by the superposition between the Meso-Neoproterozoic and its overlying source rocks and this assemblage is mainly distributed in Hangjinqi and Pingliang areas with the Carboniferous-Permian shale sequence as its caprock. The dynamic evaluation on the displacement pressure serves to reconstruct the displacement pressure history of the caprock. The results show that the shale sequence of the Cambrian Maozhuang Formation in well XY 1 in the southern Ordos Basin has possibly acquired the ability of sealing natural gas since the early of Late Triassic. Its displacement pressure increased rapidly up to 20 MPa during the Late Triassic-Jurassic and keeps at 9.2 MPa at present, indicating fair sealing ability. The Carboniferous-Permian caprocks in Hangjinqi area could have acquired the ability to seal natural gas in the Late Jurassic-Early Cretaceous, and the present-day displacement pressure is 9e12 MPa, indicating good sealing ability. The upper Paleozoic caprock in Pingliang area has been able to seal natural gas since the Early Jurassic, with a maximum displacement pressure of 23 MPa during the Cretaceous period and a current value of 17 e20 MPa, indicative of strong ability to seal natural gas. The sealing ability of caprocks of both the "selfsourced indigenous" and "upper source rock - lower reservoir" assemblages has come into being earlier than or at least no later than the peak gas generation of the source rocks and therefore the caprocks are dynamically effective in geohistory. The Meso-Neoproterozoic reservoirs in the Ordos Basin are well preserved and probabally of better potential for exploration in terms of the caprock-source rock combination. [ABSTRACT FROM AUTHOR]

The physical properties of the rock units associated with the Rio Bonito Formation are presented in this study with the focus on modelling reservoir quality based on petrophysics-derived parameters to evaluate CO2 storage potentials. It involves the modelling of the reservoir depths, thicknesses, flow zone indicators (FZI), and effective permeability (Keff) and presenting the CO2 storage efficiency factors peculiar to the rock units of the study location. Research results presented by this study for the stated objectives are not quite common in the region. Keff values range from 200 mD to higher than 2000 mD, and FZI values are generally above 1.0 mm and up to 13.0 mm within the portions covered by the drilled wells. The sandstone units recorded are up to 20 m thick in some cases. The Keff and FZI models indicate the sandstone reservoirs as permeable units to support the injection and circulation of CO2 within the potential reservoir units of the Rio Bonio Formation across São Paulo State. Apart from some points in the southeastern part of the study location, where the Rio Bonito are delineated at depths less than 800 m (minimum CO2 storage depth based on best practices), other portions are deeper, ranging from 950 m to 3500 m. Thin-bedded layers will affect the integrity of the rocks as CO2 storage tanks or reservoir seals/traps/overburden within the region. Sandstone bed thicknesses are up to 20 m in some cases. However, hybrid CO2 reservoir units are feasible, especially in portions where thin siltstone layers are sandwiched between sandstone units to provide considerable thicknesses based on CO2 storage standards. The current study shows that useable areas considering reservoir thickness, depth, and other physical qualities will significantly control the CO2 storage efficiency of the study location. Further studies featuring a detailed geophysical exploration of the site to confirm the availability and saturations of preexisting fluid (hydrocarbon and water) are encouraged to boost CO2 storage in the region. The related research-based results, as mentioned above, may be combined with the results of this research to determine the area's potentials for CO2 storage or hydrocarbon production with CO2 storage options. [ABSTRACT FROM AUTHOR]

Drilling for karst hydrothermal resources in eastern China has posed challenges, including disparities between the temperature and yield of geothermal water. It is evident that relying solely on geothermal anomalies or indications of karst reservoirs is inadequate for the exploration of karst hydrothermal resources. This study seeks to elucidate the cause of geothermal sweet spots by analyzing the interplay between geothermal anomalies and karst reservoirs and the underlying geological conditions for karst hydrothermal enrichment. Key findings include: (1) the Bohai Bay Basin has been geologically favorable for the development of karst hydrothermal resources since the Mesozoic era; (2) the karst hydrothermal enrichment varies significantly between the basin's margin and its interior. On the basin margin, the enrichment is largely driven by groundwater activity and faults, particularly where faults facilitate the upwelling of geothermal water. In contrast, within the basin's interior, karst hydrothermal resources are predominantly influenced by buried hills and are especially enriched in areas facilitating the discharge of deep geothermal waters. [ABSTRACT FROM AUTHOR]

The geological conditions of hot dry rock (HDR) reservoirs are complex. The geothermal mining of HDR faces major challenges in the drilling and construction of wells, fracturing to create storage, and flowing to extract heat. Vibration impacts help improve the rock-breaking efficiency, where the axial–torsional coupled vibration impact technology can increase the bit penetration depth and reduce the stick–slip effect. To study the feasibility and efficiency of the axial–torsional-coupled vibration impact-assisted Polycrystalline Diamond Compact (PDC) bit to break high-temperature and high-pressure rocks, a new experimental setup was designed. The system includes a drilling fluid circulation system, an axial–torsional coupled impact drilling system, a formation simulation system, and a data acquisition and control system. This setup can produce a rock-breaking torque of 2000 N·m, a drilling speed of 200 rpm, a weight on bit of 100 kN, an axial vibration frequency of 100 Hz, and a torsional vibration frequency of 50 Hz. It can simulate the formation pressure of 70 MPa and the rock temperature of 400 °C. A series of rock-breaking drilling experiments were successfully conducted using this setup. The results show that the axial–torsional coupled vibration-impact assisted PDC bit has a good performance in breaking high-temperature and hard rocks, which can accelerate the application of this new technology in deep formation drilling. [ABSTRACT FROM AUTHOR]

The article describes the development stages of an adequate regulatory structure for the slope stability in open pit mines. Some supplementary factors that have influence on stability of slopes in open pit mines in the gravity–tectonic stress field are discussed. The main trends of research of pitwall rock mass in operating surface mines are presented, and the necessity of determining the tectonic stresses in pitwall rock mass and taking into account their impact on slope stability is emphasized. The algorithm is developed for justifying slope parameters for open pit mines under tectonic stresses, the drilling-and-blasting principles are formulated for the operation in pitwall rock mass, and the methods are proposed to mitigate the blasting-induced impact on adjacent rocks. [ABSTRACT FROM AUTHOR]

The Bozi-Dabei area in the Kuqa Depression host high-quality reservoirs in the Bashijiqike Formation and Baxigai Formation sandstones of the Lower Cretaceous, in which reservoirs yield significant industrial gas flow despite being situated at a considerable burial depth of 8200 m. The geological history of the target formation involves multiple phases of tectonic movements, resulting in the development of multi-genetic fractures that enhance the reservoir's storage and seepage capacity. Based on the results of the drilling core, field profile survey, imaging logging, and experimental analysis, this study presents an analysis of fractures in the Lower Cretaceous dense sandstone reservoir of the Bozi-Dabei area, andclarifies the characteristics and controlling factors of the multi-genesis and multi-period fractures. Additionally, it proposes an effective fracture development model that accounts for geo-stress control. In the Bozi-Dabei area, the prevailing high extrusion stress environment has led to the development of predominantly regional tectonic fractures and fault-related fractures, with relatively gentle deformation-related fractures. The results of a combination of multi-attribute data determination techniques, including fracture filling, inter-cutting relationship, fracture filling isotope, inclusions, and cathode luminescence tests, this study reveals that the reservoir fractures have experienced three major periods of tectonic movement. The regional tectonic fracture development is mainly controlled by stratigraphic lithology and thickness, while the proximity influences fault co-derived fractures to the fault and the relative positions of the upper and lower plates of the fault. The shift in the direction of the late horizontal maximum principal stress leads to the opening or closing of early fractures under different conditions in the Bozi-Dabei area, consequently affecting the degree of fracture opening and effectiveness. Notably, when the horizontal maximum principal stress is deflected to intersect with early fractures at a smaller angle or even superimpose, the fracture effectiveness of the related group system in the deflection direction improves, resulting in an overall coordination. The distribution characteristics of the fracture system in this highly productive reservoir are the result of dominant configurations from multi-phases of geological activities. [ABSTRACT FROM AUTHOR]

The evaluation of remaining reserves is crucial for assessing the developmental effect and further enhancing the recovery of a gas field. In this research, with the Changning shale gas field in the southern Sichuan Basin as the center of study, a comprehensive analysis was conducted on reservoir distribution, remaining reserves, and strategies to enhance recovery through the utilization of diverse methodologies, including organic geochemical testing, triaxial rock mechanics experiments, and numerical simulations. The results show that, in the study area, the recovery percentage of the well-controlled reserves ranges from 45% to 70%, with the average remaining reserves of wells falling within the (50-150) × 106 m3 range, alongside the potential for additional development in specific local areas. The Changning shale gas field exhibits three distinct types of undeveloped reserves, identified in areas where no wells have been drilled, inadequately fractured zones, and vertically undeveloped areas, respectively. In the areas where the average remaining reserves of wells are exceeding 100 × 106 m3, wells for repeated fracturing are selected depending on the coupling of geological, engineering, and development. In the case of well infilling, areas characterized by developed reticular fractures and existing well spacing >500 m are prioritized, taking into account the surface wellsite conditions. Through an extensive analysis, which include reservoir assessments, rock mechanics evaluations, and numerical modeling, sublayer? is identified as the optimal target in the upper gas interval, with a vertical distance of more than 20 m from sublayer? in the lower gas interval. Zones with well-developed reticular natural fractures, a pressure coefficient >1.2, and a continuous thickness of Class I reservoirs in the upper gas interval >10 m, are selected for staggered tridimensional development with an expected increase in the platform-level recovery percent by 30%. These findings can provide valuable references and guidance for the deployment of well patterns in shale gas blocks. [ABSTRACT FROM AUTHOR]

In order to ensure the reliability of drilling tractor in the downhole operation, three high‐temperature and high‐pressure sealing mechanisms are designed in this paper to balance the pressure difference between the inside and outside of the drilling tractor, namely the triangular, the U‐shaped and the right‐angle combined sealing structure. In this paper, three models of combined sealing structures are established, the contact stress of different contact surfaces of the three combined sealing structures is analysed by simulation method, and their sealing performance is studied and compared. By comprehensively comparing the effects of pre‐compression ratio, working medium pressure and reciprocating motion on the sealing effect of the three combined sealing structures, the optimal combined sealing structure of the drilling tractor is selected as the U‐shaped combined sealing structure. The research results of this paper can provide reference and theoretical basis for the design and selection of the combined sealing structure. [ABSTRACT FROM AUTHOR]

By far a large scale of industrial components is being manufactured from metallic materials. Most of these components possess holes in order to fulfill design and application requirements, such as assembly of screws, pins or passing channels for fluids. Depending on the utilized manufacturing method and positioning of these components during machining processes, these holes are being drilled even in vertical or inclined orientations with respect to the jig and fixturing systems. In vertical drilling of the flat surfaces conventional or indexable inserted drill are the commonly used tools. However, these types of tools do not demonstrate sufficient performance on the surfaces drilled holes due to the occurred run-out, vibrations when being used in inclined features. Therefore, flat bottom drills have been developed in order to be used for curved or inclined surfaces. Thus, optimization of the tool and components design requires a deeper knowledge on the cutting forces and torques when using flat bottom drills. In this study, a predictive analytical cutting force model is developed for flat bottom drills for both vertical and inclined plunging using mechanistic approach in Matlab. The model is established on the distributed elementally cutting along the tool radius considering both rake and relief faces based upon the orthogonal and oblique cut principles. Accordingly, the performance of the developed model for different cutting tools with various geometries and machining parameters have been evaluated and verified with experimental results of flat bottom drilling of brass alloy. [ABSTRACT FROM AUTHOR]

With the development of petroleum exploration and drilling, the current drilling tools are facing more difficulty situations, which lead to these problems such as low drilling speed, weak rock breaking ability or short service time. Based on this background, we propose a new drilling tool is proposed in this paper. By analyzing the force of the cam roller system, the dynamic differential equations of the horizontal drill string are established. The key parameters' influences on the axial impact force of the new tool are studied first. Based on the new outputs, the vibration characteristics of drill string system are studied. For discovering the internal mechanism, the impact part dynamic analysis of this new tool is carried out, so as the contact force between roller and cam, the impact force between upper shaft body and pad. Furthermore, for verifying the rationality and accuracy of theoretical calculation, these parameters' results are compared and analyzed under different drilling weights. Through laboratory and field tests, the impact frequency and impact force of this new drilling tool are analyzed, the effectiveness of theoretical models are also demonstrated. This research can provide an effective technical references to solve the current drilling difficulty in new situations. The rotary impact screw drilling tool has the function of impact while rotating, realizing the combination of shear and impact rock breaking, so as to improve the mechanical drilling speed. The impact load on the drill bit is produced by the combined action of hydraulic and mechanical forces. The impact force is generated in the form of mechanical structure movement, and it is a continuous and stable periodic impact force, which makes the bottomhole assembly produce benign vibration. Through experiments, the effectiveness of theoretical calculation and dynamic model is proved successfully, and the drilling tool can effectively improve the drilling rate. [ABSTRACT FROM AUTHOR]

The authors show that data on characteristics of drill mud penetration zone improve reliability of geoinformation obtained from borehole geology and geophysics. The developed procedure for the data interpretation takes into account the geomechanics and hydrodynamics of drilling. A part of the drill mud penetration zone is represented by mudcake which prevents direct measurement of porosity and permeability. The article describes the experimental studies on growth of the mudcake on the samples of low-permeable sandstone from the Jurassic reservoir rock mass using an original facility. The petrophysical nonuniformity of the mudcake was determined. The repeated measurements revealed the mudding zone. [ABSTRACT FROM AUTHOR]

Primary manufacturing processes like casting, forming, and shaping (forging, rolling, drawing, extrusion, sheet forming, and molding) further need any of the secondary manufacturing processes like turning, drilling, boring, planing, milling, grinding, etc. In order to produce superior quality products, and to enhance productivity, the selection of desirable process parameters is significant. The selection of suitable process parameters is essential for accomplishing the desired component. Based on the existing literature, this study examines the causes, effects, and variances regarding chip formation, tool geometry, thrust force, torque, surface roughness, drilling time, and other drilling quality characteristics in the most typical machining operations such as drilling. Developing a repository on these process parameters will guide the process planning engineer for ready reckon. Therefore, this work aims at the development of a detailed repository with the study of characteristics. Further, this literature review comprehends the characteristics of a behavior with its reasoning, which was detailed in the past decade. It reveals the beneficial process parameters for achieving better production rate and superior quality. [ABSTRACT FROM AUTHOR]

The use of fiber reinforced composite materials (FRP) has increased in many areas. These materials need to be processed with some machining methods according to their usage areas, but their machinability is difficult. In this study, surface roughness (SR), delamination factor (Fd) and thrust forces were investigated in the drilling of glass fiber reinforced composite material (GFRP) produced by pultrusion with a coated and uncoated drill. Microstructures of chips formed during drilling were investigated and their effects on surface roughness were determined. Three different cutting speeds (60, 70, 80 m/min) and feed rates (0.06, 0.09, 0.12 mm/min) were selected as machining parameters. At the end of the study, it was found that feed rate had a more significant effect on surface roughness, delamination factor and thrust force. It was observed that as the cutting speed increased, the surface roughness, thrust force and delamination factor decreased. The lowest thrust force and Fd occurred at a cutting speed of 80 m/min and a feed rate of 0.06 mm/min. However, the lowest SR was obtained at a cutting speed of 70 m/min and a feed rate of 0.06 mm/min.Better results were obtained with TiN coated drills compared to uncoated drills. [ABSTRACT FROM AUTHOR]

Aeromagnetic and core drilled data covering parts of southern Nupe Basin was acquired and interpreted with the view of evaluating the mineral potential of the area through interpretation of the structural features in the area, determination of the Curie isotherm depth, and correlation of aeromagnetic outcomes with the core sample data from the area. Two major regional fault trends were interpreted: northeast--southwest (NE-SW) and NNE-SSW with minor northwest--southeast (NW-SE) directions. Two depth sources in the area are delineated, namely zone of shallow seated basement which ranges from 0.42 km to 1.5 km and zone of deeply seated basement ranging from 1.91 to 3.50 km. Results of qualitative interpretation of the total magnetic intensity map (TMI) and residual intensity map reveal that the magnetic intensities range from 7500 to 8460 nano-Tesla (nT) and -220 to 240 nT, respectively. The depths to the centroid and top of the magnetic causative bodies range from 9.00 to 17.10 km and 0.4 to 3.10 km, respectively. There are evidences of oolitic iron ore in some parts of the study area. Juxtaposing the topographical and core drilling data reveal that the oolitic iron ore level follows the topographical level which implies that the topography of the area controls the configuration of the iron ore deposit level. All these deductions are made considering the geology of the area. [ABSTRACT FROM AUTHOR]

Drilling speed-increasing tools are essential in increasing penetration rate in deep and hard-to-drill formations. This paper delves into the characteristics, application scopes, and performance advantages of commonly used tools, such as torsional impact tools, friction reduction by impact tools, positive displacement motors (PDMs), turbodrills, and Gyro Stable Drilling tools. The suitability and effectiveness of these drilling speed-increasing tools for different types of hard-to-drill lithologies are also examined. This paper serves as a reference for selecting the appropriate drilling tools in challenging drilling conditions. [ABSTRACT FROM AUTHOR]

Mining is a broad and complex field. The search for and exploitation of minerals is unceasing in many countries worldwide. Before its collapse towards the close of the 20th century, coal mining in the United Kingdom, for instance, which dates back to Roman antiquity, occurred in various regions of the country, such as Northumberland and Durham, North and South Wales, Yorkshire, Kent, and the East and West Midlands. An essential aim of the present paper is to give an overview of the plethora of mining terms in English which have been coined due to progress and advance in this field over time, ranging from terms associated with boring, drilling and extraction, to ventilation, pipelines and hauling. The Oxford English Dictionary Online (Murray et al., 1884–; henceforth referred to as the OED) and specific sources such as Elsevier's Dictionary of Mining and Mineralogy (Dorian, 1993) constitute valuable tools to identify these types of lexical items. This study relies on the analysis of a comprehensive lexicographical sample of 217 mining terms documented in English. [ABSTRACT FROM AUTHOR]

The accurate prediction of wellbore temperature and pressure is important for safe drilling. However, annulus temperature and pressure changes are more complicated due to phase transition. To study this problem, a prediction model of temperature and pressure in deep water riserless drilling is established by considering hydrate cuttings decomposition, interphase mass transfer, and phase transition heat. Based on this model, the effects of hydrate cuttings decomposition on the temperature and pressure of drilling in a hydrate reservoir are explored. The results show that the influence of hydrate cuttings decomposition increases significantly with an increase in the inlet temperature. The influence of hydrate cuttings decomposition on temperature and pressure decreases with an increase in displacement. A small range in the variation of density and penetration rates has little impact on the annulus pressure but mainly affects the temperature. The influence of hydrate cuttings decomposition increases with an increase in the penetration rate. In normal drilling conditions, hydrate cuttings decomposition has little impact on annulus temperature and pressure, but under the conditions of a high inlet temperature, high hydrate saturation, low displacement, and high penetration rate, it is necessary to consider the impact of hydrate cuttings decomposition. This study can provide reference for the prediction of temperature and pressure in deep water hydrate reservoir riserless drilling. [ABSTRACT FROM AUTHOR]

With the increasing development of coiled tubing drilling technology, the advantages of coiled tubing drilling technology are becoming more and more obvious. In the operation process of coiled tubing, Due to various different drilling parameters, manufacturing defects, and improper human handling, the coiled tubing can curl up and cause stuck drilling or shortened service life problems. Circulation pressure, wellhead pressure, and total weight have an important influence on the working period of coiled tubing. For production safety, this paper predicts circulation pressure, ROP, wellhead pressure, and finger weight using GAN–LSTM after studying drilling engineering theory and analyzing a large amount of downhole data. Experimental results show that GAN–LSTM can predict the parameters of circulation pressure, wellhead pressure ROP and total weight to a certain extent. After much training, the accuracy is about 90%, which is about 17% higher than that of the GAN and LSTM. It has a certain guiding significance for coiled tubing operation, increasing operational safety and drilling efficiency, thus reducing production costs. [ABSTRACT FROM AUTHOR]

This paper presents an experimental approach to evaluate the ability of a six-axis industrial robot to drill aluminum alloy parts. A strategy based on statistical tests has been studied to quantify and predict the relative contribution of cutting parameters on cutting force and shape errors during drilling. This technique is based on the identification of relevant sources of error during high-speed robotic fitting. The machining quality was quantified in terms of dimensional and geometric tolerance, chip formation and evacuation, burr formation, edge build-up, tool wear and surface damage. Statistical analysis of the experimental results reveals a strong dependence between part accuracy and drilling force. An experimental model was developed to represent and predict the cutting force during drilling and an accurate error prediction capability was distinguished. It was found that at high cutting speed and feed rate, the cutting force was the main source of error affecting the accuracy of the machined parts. Verification experiments are performed, and the results reveal that dimensional defects are significantly reduced by a heat treatment effect (90 HRE) and the thrust force decreases with an increase in cutting speed. The recommended cutting speed for robotic drilling is 6000 rpm with a feed rate of 0.15 mm/min. This study provides important technical guidance for improving the robotic drilling of aluminum alloy in practice. [ABSTRACT FROM AUTHOR]

Despite exploration and production success in Niger Delta, several failed wells have been encountered due to overpressures. Hence, it is very essential to understand the spatial distribution of pore pressure and the generating mechanisms in order to mitigate the pitfalls that might arise during drilling. This research provides estimates of pore pressure along three offshore wells using the Eaton's transit time method, multi-layer perceptron artificial neural network (MLP-ANN) and random forest regression (RFR) algorithms. Our results show that there are three pressure magnitude regimes: normal pressure zone (hydrostatic pressure), transition pressure zone (slightly above hydrostatic pressure), and over pressured zone (significantly above hydrostatic pressure). The top of the geopressured zone (2873 mbRT or 9425.853 ft) averagely marks the onset of overpressurization with the excess pore pressure above hydrostatic pressure (P*) varying averagely along the three wells between 1.06-24.75 MPa. The results from the three methods are self-consistent with strong correlation between the Eaton's method and the two machine learning models. The models have high accuracy of about > 97%, low mean absolute percentage error (MAPE < 3%) and coefficient of determination (R2 > 0.98). Our results have also shown that the principal generating mechanisms responsible for high pore pressure in the offshore Niger Delta are disequilibrium compaction, unloading (fluid expansion) and shale diagenesis. [ABSTRACT FROM AUTHOR]

Low permeability sandstone reservoirs in China typically have more complicated geological conditions, pore structures, and flow characteristics as compared to medium-to-high-permeability sandstone reservoirs. Traditional geological and seepage theories, and engineering methods are not applicable to the development of these low permeability reservoirs, and wells drilled into them often produce oil and gas at very low rates. Recent breakthroughs in reservoir exploitation technology have greatly improved the productivity of low permeability reservoirs, making them the primary target for oil exploration and extraction in China. The development theories and practices applied to low permeability reservoirs in China are reviewed in this studyd based on relevant geological and engineering practices, including drilling, fracturing, recovery, and surface engineering. A unique series of technological advances that aid the development of low permeability reservoirs in China are summarized here. This study may serve as a meaningful guide in achieving scale efficiency for the development of low permeability reservoirs. [ABSTRACT FROM AUTHOR]

To overcome some shortcomings in conventional rotary percussion drilling, such as low impact frequency and enabling not to make the most of impact energy, this paper proposed a new rotary percussion drilling method. Based on this method, the corresponding drilling device was designed. At first, the inner structure and working principle of this device were illustrated in detail. This device has two bits, namely, internal bit and external bit. The internal bit can generate high-frequency impact on rocks and concentrate impact energy near central areas of the bottom hole. The coupled action of these two bits can produce an alternating shear stress zone, which can exacerbate fatigue damage to rocks. And then the mechanics models for analyzing alternating shear stress and impact energy were built. Finally, the effects of some key parameters on alternating shear stress and impact energy were analyzed. The key findings of this study are as follows. As blades number or dip angle of the internal bit decreases, the amplitude of the alternating shear stress increases, which is beneficial for rock fatigue damage. Moreover, as the loading and unloading speed of impact force increases, the impact energy increases, which will promote damage and fragmentation of rocks. Compared with other wave shapes, the square wave has the highest loading and unloading speed, which means its rock-breaking efficiency is the highest. The new rotary percussion drilling method proposed in this study provides a new idea to make full use of impact energy and improve rock-breaking efficiency. [ABSTRACT FROM AUTHOR]

Fused deposition models (FDMs) are the latest trends for constructing complicated and instinctive 3D printing. Polylactic acid (PLA) is the most widely used raw material in extrusion-based three-dimensional (3D) printing in many areas since it is biodegradable and environmentally friendly; however, its utilization is limited due to some of its disadvantages such as mechanical weakness and water solubility rate. To increase the mechanical properties of the FDM, nano bronze particles have been added as advanced research. Printing the hole less than a millimetre is complicated, and there is a limited report available in FDM. In this paper, polylactic acid (PLA) with a 14% bronze composite filament is made by hot extruding under the desired FDM conditions. The samples are built with 100% infilled density with 45° orientation to a sample size of 50 × 50 × 10 mm. To examine the printing state and the effect of microdrilling on the printed specimen, two different specimens are printed with and without holes. An industrial drill with specified feed, speed, and cutting width is used to perform the test. The size of the drilled hole is checked by scanning electron microscopy. The quality of the drilled hole and the wear of the tool is investigated and reported. According to the observation, it is noted that the secondary machining operation becomes unavoidable to have a hole of less than a millimetre. Machining, cutting speed, and feed speed influence the delamination zone and the circumference of the hole. [ABSTRACT FROM AUTHOR]

This work deals with the additive manufacturing by 3D printing of the Gas Reduction R2-M60x2 landmark which is part of the Gas Reduction R2-Hose DN 2 in subassembly. This sub-assembly is a component part of the washing head of the light water well drilling installations FA 100, FA 125, FH 150 and FG 40. The generic name of the washing head will be FA 100. We use 3D printing technology because, on the one hand, it is technically possible to make the part and on the other hand, for economic reasons. It is approximately ten times cheaper to make the part through 3D printing than through conventional technologies. [ABSTRACT FROM AUTHOR]

This paper deals with the additive manufacturing by 3D printing of the Dutch Nut-M60x2 landmark which is part of the subassembly Gas Reducer R2-Hose DN 2 in. This subassembly is a component part of the washing head of the light water well drilling installations FA 100, FA 125, FH 150 and FG 40. The generic name of the washing head will be FA 100. We use 3D printing technology because, on the one hand, it is technically possible to make the part and on the other hand, for economic reasons. It is approximately ten times cheaper to make the part through 3D printing than through conventional technologies. [ABSTRACT FROM AUTHOR]

This paper deals with the additive manufacturing by 3D printing of the Hose Pipe DN 50 landmark which is part of the Gas Reduction R2-Hose DN 2 in subassembly. This sub-assembly is a component part of the washing head of the light water well drilling installations FA 100, FA 125, FH 150 and FG 40. The generic name of the washing head will be FA 100. We use 3D printing technology because, on the one hand, it is technically possible to make the part and on the other hand, for economic reasons. It is approximately ten times cheaper to make the part through 3D printing than through conventional technologies. [ABSTRACT FROM AUTHOR]

It presents an element of absolute novelty for industrial scientific research in Romania, the fact that the housing of the washing head and other landmarks of the washing head from the FA100 water well drilling installations. FA125, FH150 and FG40 were made by additive manufacturing by 3D printing with PETG and ABS+ filament. [ABSTRACT FROM AUTHOR]

In this work, it is proposed to make by additive manufacturing through 3D printing with FDM technology FDM (Fused Deposition Modeling - Modeling by Depositing Fusible Filament) some landmarks of the washing head which is common to the light water well drilling rigs FA100, FA125, FH150 and FG40. A washing head like the FA100 washing head, which has the casing and the drilling fluid supply fittings, 3D printed from PETG and ABS+ filament, has never been made in Romania. The main advantages of using this manufacturing technology are that by purchasing such equipment, a large number of different landmarks can be made and the final price of the landmark. [ABSTRACT FROM AUTHOR]

The washing head is the most important sub-assembly in a water well drilling installation, and ensures the operation of the installation on the principle of "hydraulic rotary drilling with direct circulation of drilling fluid", whereby, inside the rotating drill rod assembly is injected, through the washhead, drilling fluid from the discharge of the drilling mud pump, which is fed from a pit (pit) dug below ground level. [ABSTRACT FROM AUTHOR]

Glass fiber reinforced polymer (GFRP) composites are widely used in aviation, aerospace, sports and special vehicles because of their light weight, high wear resistance, good fatigue resistance and low thermal expansion coefficient. However, the anisotropy and low interlaminar strength easily lead to defects such as wire drawing, delamination and tearing during drilling process, which seriously restricts the development of GFRP composites. In this study, the effects of drilling tool material and geometrical parameters on the machining quality of GFRP composites in ultrasonic-assisted drilling are revealed through single-factor experiment. Unidirectional laminated GFRP epoxy plates of 80 × 50 × 5 mm are used in the experiment, and the thrust in the machining process is collected by a dynamometer. An industrial camera is used to record the exit morphology of the hole, and then MATLAB is used for image processing to convert it into a greyscale map. Finally, the size of the delamination factor Fd is obtained according to the equation. The experiment results indicate that using the carbide drilling bit with a diameter of 4 mm and a point angle of 120° is beneficial to reduce the thrust and suppress the machining defects. [ABSTRACT FROM AUTHOR]

Prediction of the wellbore fluids and formation temperatures is crucial during drilling operation, especially for high temperature wells, such as geothermal applications. This work presents the applications of an improved comprehensive drilling simulator for predicting the wellbore system temperature during the drilling process. A fully transient numerical model of the wellbore temperature is developed for drilling and geothermal production applications. The model describes the dynamic behaviour of the thermal state of the wellbore during circulation and static conditions. The developed model is implemented with the commercial virtual drilling simulator through an application programming interface. This implementation allows the coupling of the thermal model with other physical models, which leads to more advanced and realistic simulations. The model has been previously validated through a direct comparison with field data from geothermal well located in the Hanover area in Germany. The results showed a good agreement between the predicted outlet fluid temperature and the measured one. Furthermore, an analysis of the effect of various parameters on the wellbore system temperature is performed. This analysis showed the impact of these parameters on the wellbore temperature profile including the critical areas such as the casing setting point and bottom hole assembly. This information may lead to enhancing the wellbore stability by monitoring the thermal stresses, especially in high-temperature wells. Moreover, predicting the drill bit temperature can result in increasing the lifetime of the bit by adjusting the operating conditions to keep the bit temperature within the specified range. Based on these results, the enhanced drilling simulator with the transient temperature model showed to be a suitable tool for effective well planning. [ABSTRACT FROM AUTHOR]