Drill Design Research Articles

Evaluation of the insertion torque, implant stability quotient and drilled hole quality for different drill design: an invitro Investigation.

The purpose of the present study was to compare the insertion torque and implant stability quotient between different drill design for implant site preparation. Synthetic blocks of bone (type I density) were used for drilling procedures. Three groups were evaluated: Group G1 - drilling with a single bur for a 4.2mm conical implant; Group G2 and Group G3 - drilling with three consecutive burs for a 4.1mm cylindrical implant and for a 4.3mm conical implant respectively. For each group, 15 drilling procedures were performed without irrigation for 10-mm in-depth. The drilled hole quality (HQ) after the osteotomy for implant site preparation was measured in the five-first holes through a fully automated roundness/cylindricity instrument at three levels (top, middle, and bottom of the site). The insertion torque value (ITV) was achieved with a computed torquimeter and the implant stability quotient (ISQ) values were measured using a resonance frequency apparatus. The single drill (group 1) achieved a significantly higher ITV and ISQ than the multiple drills for osteotomy (groups 2 and 3). Group 1 and 3 displayed significantly better HQ than group 2. Within the limitations of the study, the results suggest that the hole quality, in addition to the insertion torque, may significantly affect implant primary stability.

Increase in efficiency of quality and hole-making in glass-reinforced titanium laminate by reducing drilling vibroactivity

The work objective is to study the impact of the drill design value and geometrics on the quality of the processed holes, the efficiency, and the machining dynamics of the high-strength polymer composite - fiberglass plastic reinforced by titanium foil. Packs of the reinforcing layers made from the titanium foil or carbon fiber tapes are often used in the highly-loaded polymer composite structures. Processing in several operations and the application of sharp-ground tools provide the required dimensional accuracy, the surface macro- and microgeometry of the hole, and allow avoiding the delamination. The process of drilling fiberglass laminates under different patterns of HSS drills sharpening is studied. The data obtained allow determining the optimum type of instrument and operation mode taking into account the dependence of the high-altitude roughness parameters, the nature and amount of delamination in the entry (exit point) of the drill. The vibroactivity of the drilling process and its relationship with the quality metrics are studied using the computer-aided torque-sensing system. Some proposals for improving the hole-making technology applying to the glass-fiber spars of the main and tail helicopter rotors are developed.

Innovative agro-engineering solutions in design of drills for sugar and fodder beet

Technical level of precision seed drills for sugar and fodder beet is analyzed. Faults in their design and technology such as non-uniformity of seeding and seed germination, unsatisfactory process reliability are revealed. For the purpose of faults removal, it is proposed to equip drills additionally with new working organs.

水平井井眼轨迹控制误差分析

随着诸多新型定向井、水平井(如分支井、丛式井、大位移井、绕障井、SAGD水平井、火驱井等井型)的应用，所钻遇的地质环境日趋复杂，在井眼密集的老区和超薄边际油层钻井中，对水平井井眼轨迹监测与控制的精度要求越来越高。由于随钻测量仪器在测量过程中由于受到环境、仪器精度、磁场变化等因素影响，实钻井眼轨迹就会与设计轨道产生偏差。认识测量仪器误差对轨迹控制的重要性，减小井眼轨迹控制的误差，提高井眼轨迹的控制精度，可以有效降低井眼防碰的风险，也可以提高水平井的中靶精度，对水平井的现场施工具有重要的指导意义。 With many new directional wells and horizontal wells (such as Multilateral wells, Cluster wells, ERW, SAGD, Fire Flooding wells) application, the geological environment is becoming more com-plex. The accuracy requirement of monitoring and controlling the trajectory of horizontal well in drilling is higher and higher, especially in the old wells and ultra dense marginal reservoirs wells. Due to the environment, the precision of the instrument, the change of the magnetic field, and so on, the influence of the factors on the measuring instrument in the measuring process is measured. So there is deviation between the real drilling trajectory and design trajectory. By recognizing the importance of measuring instrument error on trajectory control, this error can be reduced in slim hole trajectory control, and it also can improve the control precision of the well trajectory. It can reduce the risk of well drilling and improve the accuracy of the target. It has great realistic significance to field operation.

Analysis and test research on influencing factors of drilling and coring quantity of lunar soil simulant

During the design of drilling and coring mechanism for lunar exploration,a coring method based on a flexible tube can obtain slim continuous sample core,which enables high coring rate and preserves the stratification information of the subsurface samples. Since the complex movement of lunar soil particles during the flexible tube coring,there is no systemic method to analyze the factors that determine the coring quantity. The flowage of the lunar soil particles in flexible tube was analyzed and the coring model of the flexible tube based on the theory of limit equilibrium was established. The mechanical boundary conditions of the model were interactions between lunar soil and coring drill tools and among each part of lunar soil. The coring model described the dynamic process of lunar soil flowing from the outside of coring drill tools into the flexible tube. A numerical prediction method for coring rate was proposed based on the coring model. Drilling parameters,lunar soil properties and drill tool structure were analyzed as key influencing factors of coring rate. A verifying test with simulant of lunar soil HIT-LS1# and drill tools HIT-2 was implemented on a simulated drilling test-bed. The average error between the test results and the predicted results is less than 5%.

Tool geometry based prediction of critical thrust force while drilling carbon fiber reinforced polymers

Carbon fiber reinforced polymers (CFRPs) are known to be difficult to cut due to the abrasive nature of carbon fibers and the low thermal conductivity of the polymer matrix. Polycrystalline diamond (PCD) drills are commonly employed in CFRP drilling to satisfy hole quality conditions with an acceptable tool life. Drill geometry is known to be influential on the hole quality and productivity of the process. Considering the variety of CFRP laminates and available PCD drills on the market, selecting the suitable drill design and process parameters for the CFRP material being machined is usually performed through trial and error. In this study, machining performances of four different PCD drills are investigated. A mechanistic model of drilling is used to reveal trade-offs in drill designs and it is shown that it can be used to select suitable feed rate for a given CFRP drilling process.

Main directions of electric drill improvement

The article provides information about the history of electric drilling; performance indicators of electric drilling are shown. The design and features of the serial electric drills, their components and assemblies are described in detail. Design reliability and experience of use are estimated.Theoretical calculations made by Professor Kikot O.V. provide an opportunity to create a new design of electric drill DC. The conceptual design of such electric drill together with construction advantages is provided.New electric drill will allow quickly change the frequency of the bit rotation and increase drilling penetration rate

Effect of Molecular Weight of Polyethylene Glycol on the Equilibrium Dissociation Pressures of Methane Hydrate System

The experimental phase equilibrium data for methane (CH4) clathrate hydrates in the presence of polyethylene glycol (PEG) aqueous solutions with various number-average molecular weights of 200 kg/kmol (PEG-200), 400 kg/kmol (PEG-400), and 600 kg/kmol (PEG-600) for (0.077, 0.2, 0.4, 0.44 and 0.46) mass fractions at the temperature range (270.75 to 281.45) K and pressure range (4.60 to 7.05) MPa has been reported. The isochoric pressure-search method is used to generate the equilibrium data on the hydrate system. Comparative effects of PEG-200, PEG-400, and PEG-600 aqueous solutions at various concentrations (mass fraction and mole fraction basis) on the methane hydrate system have been studied. The inhibition effect using low molecular weight PEG-200 is observed to be more effective in suppressing the methane hydrate formation than PEG-400 and PEG-600 at the same mass fraction. On the mole fraction basis, at higher concentration, the inhibition effect of PEG-600 on the methane hydrate system at the same mole fraction is observed to be more than PEG-200. Surprisingly, at lower concentration (at the same mole fraction), PEG-200 is observed to inhibit the methane hydrate system more than PEG-600. The methane hydrate suppression temperature using PEG-200, PEG-400, and PEG-600 is also determined using Hammerschmidt’s equation and are reported. The work also reports the values of enthalpy of dissociation determined using the Clausius–Clapeyron equation for a methane hydrate system in the presence of PEG-200, PEG-400, and PEG-600 aqueous solutions. The enthalpy of dissociation of methane hydrate is observed to increase with increasing molecular weight of PEG. The study shows the effectiveness of low molecular weight PEG in inhibiting methane hydrate as compared to higher molecular weight, thus indicating their possible use for effective design of drilling and completion fluids for hydrate bearing formation.

Thermo-mechanical effects in drilling using metal working fluids and cryogenic cooling and their impact in tool performance

Cryogenic machining opens up new industrial perspectives in difficult-to-cut materials like nickel-based alloys. In particular, drilling is an operation that generates high thermal and mechanical loading to the drill. Therefore, tool performance, hole geometry and surface integrity can be highly affected. The objective of this study is to analyse tool performance during drilling of IN718 using conventional metal working fluids (MWF) and cryogenic cooling conditions, and correlate it with the thermo-mechanical phenomena. This study is conducted with standard coated cemented carbide twist drills, designed to work with MWF. The results show that drill performance under cryogenic cooling is strongly affected by its geometry. The axial force, drilling torque and tool wear/failure are higher under cryogenic cooling when compared to conventional MWF. Therefore, in order to take advantage of the cryogenic machining, new drill design is required, which currently is not available on the market.

Investigation of chip formation and burr control in PCB fixture hole

Purpose – This paper aims to analyze their generation mechanism and factors influencing burr generation. The final goal is to use appropriate drill design and drilling process to control the generation of burrs. Design/methodology/approach – The mechanism of burr generation was studied through finite element method (FEM) simulation and drilling experiments. High-speed photography technology and scanning electron microscope (SEM) were used in this study. Findings – High-speed drilling burr is a printed circuit board (PCB) copper foil burr. Within a certain range, the feed speed and burr height is in positive correlation, and decrease in the feeding speed will favor the exit burr. Drill angle influences burr and chisel edge affect significantly, followed by the point angle, and helical angle has little effect. From the perspective of reducing the burr, a smaller chisel edge and smaller point angle should be chosen. Grinding chisel edge is another choice to decrease the burr but also ensures the blade strength. Originality/value – This paper investigates the mechanism of burr generation of PCB fixture hole drilling. The process of burr generation was captured by high-speed camera. The controlling methods of burr generation were illustrated at the end.

Effects of the wellbore parameters of radial horizontal micro-holes on the gas reservoir production rate

Radial horizontal drilling technology can create several drainage micro-holes to improve the efficiency of fluid flowing from the reservoir into the wellbore, increase the single-well production rate and enhance the recovery of natural gas. This paper proposes a steady-state model to calculate the production rate of natural gas for radial horizontal micro-holes by coupling the reservoir inflow model and the wellbore flow model. The newly developed model calculates the friction pressure loss for gas flow in the radial horizontal wellbore. The influences of certain wellbore parameters on gas production rate have been analyzed, and a sensitivity study has been performed. The results show that the production rate increases as the wellbore length, the number of micro-holes, the included angle and wellbore diameter increase. However, the effects of the number of micro-holes, the included angle and the wellbore diameter are significant only within certain limits. Based on the degree to which the parameter positively affects the gas production rate, the wellbore parameters can be ranked as follows: wellbore length > the number of micro-holes > included angle > wellbore diameter > distance between the micro-hole and the lower boundary. The wellbore length and the number of micro-holes have the greatest influence on the production rate of multiple radial horizontal micro-holes. The models and results presented in this paper can provide the theoretical basis for the design of radial horizontal drilling in natural gas reservoirs.

Determination of drilling fluid rheology under downhole conditions by using real-time distributed pressure data

One the most important tasks during any drilling operation is to measure rheological properties of drilling fluids to allow for optimum maintenance and wellbore hydraulics management. In current drilling practice, such measurement is routinely carried out by a mud engineer at the rig site using test protocols and equipment that quantify the relationship between the fluid's shear stress and shear rate, as standardized by the American Petroleum Institute (API). Usually, measurements are conducted at atmospheric pressure and standardized temperature and are therefore generally not representative of actual downhole pressure and temperature conditions. High Pressure High Temperature (HPHT) viscometers can of course be used at the drilling fluid design stage to determine its rheological properties under downhole condition. However, these properties are subjected to change during drilling operations due to variation in mud maintenance and the introduction of drilling solids and contaminations. In addition, installation of a HPHT viscometer at the rig site is highly impractical due to its cost, maintenance, calibration difficulties, and lack of dedicated personnel to run the equipment.This paper presents a novel method to determine mud rheological parameters in real-time by using downhole sensor data. The well itself is used as the equivalent of a large pipe viscometer, with pressure measurements conducted along its length using multiple sensors placed at strategic positions in the drillstring. Contrary to traditional methods, rheology determination is performed at actual downhole pressure and temperature, without any human interaction and without the need for any rheology measurement equipment on surface. Frictional pressure loss is recorded at several flow rates, preferably while ramping up pump rates after making connections, and parameters associated with two- and three-parameter rheological models (e.g. the n, K and τy parameters of the Yield Power Law (YPL) also known as Herschel-Bulkley model, which most accurately describes the majority of drilling fluids) are derived. In addition, time-dependent fluid characteristics such as gel strength can also be quantified using this method. Pressure data sets from wired drillpipe during field trials with a 12.6 ppg and 13.1 ppg synthetic based muds were used to validate the applicability of the new method in the field. These validations show that the method can be applied successfully in the field when downhole distributed pressure data is available.This novel approach represents a significant step in the direction of achieving full automation of drilling fluid property monitoring and maintenance with an elegant method that requires no human interaction, eliminating the need for surface measurement equipment, while at the same time representing more accurately the downhole pressure and temperature environment. Given the importance of accurate rheology characterization, particularly in the new era of active annular pressure management using Managed Pressure Drilling (MPD) and Dual Gradient Drilling (DGD) techniques that rely heavily on accurate hydraulics modeling, the benefits are self-evident.

The effect of drill design on stability and efficacy of dental implants

Purpose : The objective of this research was to investigate an optimization of drill design factors for implant stability and efficacy through comparative evaluation by the cutting time, heat generation and initial stability. Materials and Methods : Three design factors were considered for the purpose of drill design optimization; the number of flute(2 flute, 3 flute), helix angle(15°, 25°) and drill tip shape(straight, 2-phase). Design factors were selected through comparative evaluation by temperature change, cutting time and ISQ value. Results : Heat generation and cutting time are influenced by all design factors(p<0.05). Drill tip shape was the only factors which influenced to the largest initial stability(p<0.05). Conclusion : Drills with 2 flutes, 2-phase formed drill tip, and 25 degrees of helix angle exhibit a better performance than other design.

Technology Focus: Formation Damage (February 2015)

Technology Focus Brant Bennion, in the Journal of Canadian Petroleum Technology Distinguished Authors series, titled his 1999 article on formation damage “The Impairment of the Invisible by the Inevitable and Uncontrollable, Resulting in an Indeterminate Reduction in the Unquantifiable.” This is a brilliant definition of formation damage because it reflects very well the lack of relevant data (in particular, permeability data) that are essential for adequate design of drilling and completion fluids. In addition, the opening sentence in Bennion’s article is as relevant today as it was in 1999: “Formation damage is a hot topic these days—with justifiable reason as we move to the exploitation of more challenging oil and gas reservoirs in tighter, deeper, and more depleted conditions.” In order to avoid some of the detrimental effects of formation damage, a key aspect is laboratory testing of representative core material under representative downhole conditions. Thin sections, dry scanning electron microscopy (SEM), cryogenic SEM, and X-ray diffraction have been used for a number of years to identify the main damage mechanisms, mechanical or liquid, contributing to the observed returned permeability measurement from coreflooding. High-resolution images can be obtained from dry and cryogenic SEM, but they offer only a limited view at any one time. One technique that has been applied recently to identify and quantify potential formation damage is that of microcomputed tomography (CT). This provides high-resolution scans of whole plugs and allows, for example, the identification of changes in pore structure because of fines mobilization, and the visualization of the filter cake after cleanup, depth of mud solids, and filtrate invasion. The combination of micro- CT with techniques previously used for formation-damage analysis is providing new understandings in the interaction of drilling and completion fluids with core material. One of the more frustrating aspects of coreflooding has been how to relate the results obtained to potential well-inflow performance. Computational fluid dynamics is one technique that appears to have bridged this gap. This technique incorporates the data obtained from coreflooding into a model that recreates the actual well geometry, depth of formation damage, mud thickness, and distribution of restrictions in the tubing, such as safety valves. With this approach, production rates can be obtained that provide useful insights into selecting appropriate drilling and completion fluids, for example. Enjoy the papers selected. Formation damage is still a “hot topic.” JPT Recommended additional reading at OnePetro: www.onepetro.org. SPE 165092 Case-Study Analysis of Formation Damage Induced by Brine Workover Fluid on Burcioaia Reservoir (Romania) and Research on Damage- Removal Methods by A. Dragomir, OMV Petrom, et al. SPE 165169 Formation Damage and the Importance of a Rigorous Diagnostic: A Case History in Nigerian Deep Water by Jean-Noel Furgier, Total, et al. SPE 169435 Integrated Analysis To Identify and Prevent Formation Damage Caused by Completion Brines: A Colombian Field Application by M.G. Jaimes, Ecopetrol, et al.

Comparative Analysis of PCD Drill Designs During Drilling of CFRP Laminates

As a result of increased use of CFRPs in the aerospace industry, the machining of CFRPs has been studied extensively. The majority of these studies consider drilling of CFRPs, since it is the most common process in the machining of structural parts used in aircraft. It has been shown that drilling process parameters and drill geometry significantly influence the quality of holes. In this study, a systematic approach has been used to compare the influence of drill geometry on process outputs such as drilling forces, torques and tool wear. Custom-made double point angle polycrystalline diamond (PCD) drills from the same manufacturer were used in the experiments. The advantage of this approach is that it eliminates the drill material and edge preparation effects on the experimental measurements, thus helps reveal the influence of drill geometry on the process outputs.The pros and cons of different drill designs are discussed and an appropriate design is identified for the drilling of thick CFRP laminate considered in this study.

Influence of the implant drill design and sequence on temperature changes during site preparation.

The purpose of this study was to compare bone temperature changes during implant drilling with two drill designs employed in three different drilling sequences. Two implant drill designs and three drilling sequences were evaluated in vitro using artificial bone cylinders. The evaluated drills were different only in the cutting-surface length (control, 16 mm; test, 4 mm). Three drilling sequences (control A, test B1, and test B2) were evaluated with and without irrigation. Temperatures were measured with thermocouple technology. The temperature changes generated by the final drill of each sequence were recorded as the experimental results and were subjected to the Student t test. There were statistically significant differences in temperature changes when comparing the control group A with the test groups B1 (P = .001) and B2 (P = .01) during drilling without coolant. The mean temperature changes were 12.4°C, 6.5°C, and 13.7°C for groups A, B1, and B2, respectively. The Student t test showed statistically significant differences between temperature changes of the control group A and the test groups B1 (P < .01) and B2 (P < .05) during drilling with coolant. The mean temperature changes were 0.9°C, 0.7°C, and 1.9°C for groups A, B1, and B2, respectively. Reduction in length of the cutting surface of the drill may limit frictional heat. Drills with the same length of cutting surface may induce lower bone temperature changes, when considering a preliminary drilling step with a pilot drill.

A study of an improved cutting mechanism of composite materials using novel design of diamond micro-core drills

Core drilling at small diameters in carbon composite materials is largely carried out using diamond electroplated tools consisting of hollow shafts and simplistic geometries that are likely to work in an abrasional/rubbing mode for material removal. The paper reports a step change in the performance of small diameter core drilling by facilitating a shearing mechanism of the composite workpiece through the utilisation of a novel tool design. This has been achieved by laser producing core drills from solid polycrystalline diamond, incorporating controlled cutting edges where the geometries are defined. To evaluate the efficiency of the shearing vs. abrasion/rubbing cutting mechanisms, a critical comparison between the novel (defined cutting edges) and the conventional electroplated tools (randomly distributed micro-grains) has been made with reference to thrust forces, tool wear mechanisms and their influences on the hole quality (e.g. delamination, fibre pullout). This work has been augmented by studies using high-speed thermal imaging of the two tool types in operation. The examinations have shown that, based on the concept of defined cutting edges in solid diamond, there is the possibility to make significant improvements in core drilling performance, (ca. 26% lower thrust force, minimal tool surface clogging, lower drilling temperatures) resulting in improved cleanliness of fibre fracture and a reduced tendency of material delamination.

Multistepped Drill Design for Single-Stage Implant Site Preparation: Experimental Study in Type 2 Bone.

To evaluate an experimental multistepped drill for single-stage implant site preparation by means of real-time analysis of thermal variations during and postdrilling, and by implant stability evaluation. Temperature and time were recorded in real time by paired microprobe thermocouples during simulated osteotomy in type 2 bone similes at the cortical and cancellous zones. Three different drilling groups with a new multistepped drill design were compared: Control (2-mm diameter pilot drill + 3.3-mm three-stepped drill + 4.1-mm three-stepped drill); Test A (3.3-mm three-stepped drill); and Test B (4.1-mm three-stepped drill). Implants were inserted, and implant stability was evaluated with the Perio Test Value (PTV). Two-way anova was used to test the independent effects of osteotomy and implant diameter on temperature and stability. All the drills induced thermal changes without significant differences between groups (p > .05). Drilling in cortical bone produced significant increase of the temperatures in a range of 1.8 ± 0.9°C compared with drilling in cancellous bone (p < .05). ΔT temperatures were significantly higher for test groups in cortical and cancellous bone (p < .05); ΔT10 for all groups showed a reduction of the temperature in a range of 1.7 ± 0.3°C without significant differences between groups (p > .05); the mean time to accomplish drilling was significantly longer in the control group (p < .05); test groups took 10 ± 0.3 seconds less to reach the required drilling depth. PTV values were higher in test groups compared with controls (p < .05). The multistepped drills used for single-stage implant site preparation Increase temperature as in comparison with a conventional incremental protocol; Induce the temperature increment in cortical bone compared with the cancellous bone; Reduce drilling time when a multistepped drill is used alone; and Increase implant stability twofold compared with a conventional incremental protocol.

Drilling Engineering Design and Application of Well Fengshen-x601

Thick gypsum and glutenite exist in Fengshen block, which brings a lot of technical problems in drilling construction, therefore, the drilling engineering design optimization of well Fengshen-x601 was launched. Based on the drilling purpose and combined with the actual drilling information of offset wells, the five-intervalled well track and the well structure with four layer casing were adopted in this well, the HJT537GK high efficiency cone bit was recommended in glutenite formation, and saturated saltwater polysulfonate lubricating drilling fluid system was used in gypsum section, through these measures, safety drilling was guaranteed in this well. The average rate of penetration was 3.15 m/h in the actual drilling operation, which increased by 13% compared with the offset wells, in addition, there were no accidents and complex situations. These effective implementation provided some guidance and reference for drilling operations of in the similar block. Key words : Well track with five-intervalled; Gypsum; Glutenite; Drilling design; Fengshen-x601

Design of a Downhole Motor Drilling Experimental System

In order to research the technology of impregnated diamond core bit and turbodrill which can be applied to the oil and geological field, this paper here designed a set of downhole motor drilling experimental system. We built a virtual prototype simulation model by using Solid Works which can help us dynamically design and optimize the key components and the overall structure of the whole system. In this paper, virtual assembly is available to assess the feasibility of the overall design. While the model simplification and the simulation check of the key components were carried out. Finally, we will be able to verify the correctness of the virtual prototype simulation analysis by setting up a physical prototype.