Conventional Drilling Research Articles

Comparison of heat production and bone architecture changes in the implant site preparation with compressive osteotomes, osseodensification technique, piezoelectric devices, and standard drills: an ex vivo study on porcine ribs

This study aimed at investigating differences in heat generation and bone architecture following four different implant site preparation techniques: compressive osteotomes, conventional drills, osseodensification (OD mode with osseodensification drills), and piezoelectric systems. Porcine rib bones were used as a model for implant surgery. Thermocouples were employed to measure temperature changes, and micro-CT to assess the bone architecture. The primary stability and insertion torque values of the implants placed in the differently prepared sites were assessed. The temperature changes were higher with Piezo. The average primary stability using the ISQ scale was the greatest for drills (76.17 ± 0.90) and the lowest for osteotomes (71.50 ± 11.09). Insertion torque was significantly higher with the osseodensification method (71.67 ± 7.99 Ncm) in comparison to drills, osteotomes, and piezo. Osteotomes showed the highest bone to implant contact percentage (39.83 ± 3.14%) and average trabecular number (2.02 ± 0.21 per mm), while drills exhibited the lowest (30.73 ± 1.65%; 1.37 ± 0.34 per mm). Total implant site bone volume was the highest with osseodensification (37.26 ± 4.13mm3) and the lowest for osteotomes (33.84 ± 3.84mm3). Statistical analysis showed a high primary stability and decrease in temperature during implant site preparation with osseodensification technique. The results support the use of osseodensification technique for implant site preparation.

Study on Simulation Law of Cuttings Migration in Shale Gas Horizontal Wells

Inland and offshore oil exploitation, large displacement, and horizontal well are more and more widely used, which can significantly improve the oilfield exploitation efficiency and economic benefits. However, in the complex drilling process, the debris particles generated in the large displacement and horizontal well section drilling are deposited in the lower low-speed area of the lower part of the ring empty shaft. It will cause underground accidents such as complex moving, drilling, increased resistance, drilling column fracture, and so on, which will seriously affect the efficiency and economic benefits of drilling. This paper addresses the problem of annular debris accumulation and the characteristics of high-density drilling fluid and uses the CFD-DEM (discrete cell method) method to simulate the debris movement process in the well eye based on the coupling of FLUENT and EDEM software. The edge calculation is used to provide strong resource allocation and calculation force support for this paper, fully consider the influence of the interaction between drilling fluid, debris particles, and drilling rod and well wall, and explore the influence law of the eccentric ring space of the conventional steel drill pipe.

A dynamic event tree for a blowout accident in an oil deep-water well equipped with a managed pressure drilling condition monitoring and operation system

Blowout is one of the most dreaded accidents for Oil and Gas companies. It is of particular concern during the drilling phase of deep-water oil & gas wells. This is due to the largely uncertain and extremely harsh environmental conditions that affect the design, drilling and operation activities of these wells. Seeking new technological solutions to prevent blowout has led, in the last few decades, to develop Managed Pressure Drilling (MPD) techniques.MPD offers many advantages compared to conventional drilling techniques, such as the capability (1) to detect the gas influx that initiates the kick that might lead to blowout and (2) to optimally control and circulate out this influx, to avoid the blowout. Nevertheless, effects of uncertainties on the MPD functionality are not fully understood and satisfactorily modelled within conventional safety assessment that relies on Event Trees (ETs).In this work, we propose a Dynamic Event Tree (DET) modelling framework of the scenario of kick escalation into blowout to allow accounting for the uncertainties that affect not only the kick variables, but also for the fundamental role played by the time and the delay of the kick detection task. The uncertainties affecting the kick variables are evaluated from kick events records taken from 2000 oil wells drilled in the Niger Delta, whereas the uncertainties affecting the time and delay of kick detection are evaluated by simulating the performance of the tool embedded into the MPD for kick detection (which applies the CUSUM statistical test to differential flow measurements), and assuming a possibilistic distribution for the confirmation time needed by the operator to take counteracting measures with respect to the evolving accidental scenario.A Hybrid Monte Carlo and Possibilistic method is utilized to represent and propagate uncertainties associated to the events occurring throughout the DET. Results are compared with those of a Purely Probabilistic method in support of the blowout probability quantification.

Comparison of Maximum Heat Generation during Implant Site Preparation between Single and Gradual Drilling Protocols in Artificial D1 Bone Blocks: An In Vitro Study.

Aim Two protocols for implant site preparation have been demonstrated in the literature: conventional gradual drilling and single drilling. Objectives The purpose of this study is to assess the maximum temperature changes reached during and after implant site preparation of 4.2 implant diameter using the gradual drilling protocol and single drilling protocol. Material and Methods. The artificial bone block samples (#1522–23; Sawbones, Malmö, Sweden) with the density of d1 were divided into two groups. Twelve implant site preparations were performed with the use of only one drill in group A, and the same number of preparations was performed using five gradual drills in group B. The drilling speed was set for each group at 1500 rpm with the use of external irrigation with a constant of 50 ml/min at room temperature (25 ± 1°C). The maximum temperature changes were measured using an infrared camera (Fluke Ti55, USA). The data were gathered and analyzed using Student's t-test for independent samples. Results With the 95% confidence intervals (CIs) for the means of ∆T between groups A and B, group B showed a statistically significant higher temperature change (∆T) than group A. Conclusions The current outcomes propose that the single drilling protocol, while preparing a bed for a 4.25 mm dental implant in d1 artificial bone blocks, generates less heat than the conventional gradual drilling protocol.

Effect of osseodensification on the increase in ridge thickness and the prevention of buccal peri-implant defects: an in vitro randomized split mouth pilot study

BackgroundImplant installation with conventional drilling can create buccal bone defects in areas of limited ridge thickness. Implant installation with osseodensification may aid in preventing buccal bone defects in these situations. This in vitro pilot study evaluated the impact of osseodensification on the increase in alveolar ridge thickness and the prevention of buccal peri-implant defects.MethodsTen fresh pig mandibles with limited bone thickness were selected for use in an experimental randomized split mouth pilot study. Two site-preparation protocols were used: conventional drilling with cutting burs (CTL, n = 10) and osseodensification with Densah® burs (OD, n = 10). After implant bed preparation, 20 implants (4.5 × 10 mm) were placed in the prepared sites and the insertion torque was recorded. Clinical and photographic analysis evaluated ridge thickness and the extent (height, width, and area) of bone defects in the buccal and lingual bone walls following implant placement. Three-dimensional measurements were performed using STL files to analyze the increase in buccal ridge thickness following site preparation and implant placement. The height of the buccal bone defect was considered as the primary outcome of this study. Defect width, area, implant insertion torque, and linear buccal ridge increase after implant site preparation and installation were also assessed. Non-parametric evaluations were carried out with the Mann–Whitney test to verify intergroup differences.ResultsThere was no statistically significant difference between groups in the baseline ridge thickness. OD presented a significantly higher insertion torque, associated with reduced buccal and lingual bone defect width, in comparison to CTL.ConclusionsThe increase in buccal ridge thickness after site preparation and implant placement was significantly higher in OD compared to CTL. Osseodensification increased the ridge thickness through expansion and reduced buccal bone defects after implant installation.

Decision tree approach based green flow-drilling of hybrid aluminium matrix composites using eco-friendly coolants

Green Flow-drilling is eco-friendly and has benefits such as swift execution, clean drilling, chip-free machining and easy handling which attract manufacturers from aerospace and automotive industries in the recent years. Moreover, reinforcements in aluminium-matrix composites makes drilling more complicated in conventional drilling, because of their abrasive nature. In the present work, Green flow-drilling is employed as an effective alternative for conventional drilling process on hybrid aluminium-matrix composites. Eco-friendly coolant assisted flow-drilling is envisaged to overcome the machining challenges and to accomplish uniform heat distribution across the bushing region. Various eco-friendly coolants such as rose water solution, fenugreek solution, coconut water, buttermilk solution, coconut water/fenugreek solution and buttermilk/fenugreek solution are considered. Influences of all pre-fixed input parameters on bush-length are studied employing decision tree approach that trains the experimental data and provides potential inferences for the manufacturing benefits. In specific, fenugreek solution exhibits superior temperature reduction in comparison to other eco-friendly cooling approaches irrespective of drill-rotating speeds. The application of fenugreek solution reduced the peak-drilling temperature at 216.3 °C, 317.3 °C, 376.7 °C and 439.1 °C for 550 rpm, 900 rpm, 1350 rpm and 2100 rpm respectively without disturbing the length and quality of bush. Moreover, decision tree provides wide-ranging options to select other eco-friendly cutting fluids and drill-rotating speed for targeted response (output) parameters in the flow-drilling process.

Thermal behavior prediction and adaptation analysis of a reelwell drilling method for closed-loop geothermal system

The ultra-high temperature characteristic of the deep closed-loop geothermal system poses a great challenge for drilling. This paper proposes a reelwell drilling method for temperature-controlled drilling in ultra-high temperature geothermal reservoirs. Combining the flow characteristics and heat transfer mechanisms in each flow channel under three circulating modes of reelwell drilling, a set of integrated transient heat transfer models is developed for distinct thermal-associated regions. The model simultaneously couples the effect of the variable temperature-mass flow resulting from the fluid transition in different flow channels. The finite difference method is used to solve the model, and the field measurement data is employed to validate the model. The heat transfer rate and wellbore temperature distribution in reelwell drilling are investigated, and the optimum circulating mode suitable for temperature-controlled drilling is optimized. The results indicate that the cumulative bottomhole heat flux is always negative in reelwell drilling, revealing that the bottomhole temperature decreases gradually. Additionally, the absolute values of the cumulative heat flux under different circulating modes are consistent with circulating mode B > conventional drilling > circulating mode C > circulating mode A. Thus, the circulating mode B can effectively reduce the bottomhole temperature during drilling directional well. Moreover, when a suitable dual-channel valve position is selected in the middle and lower part of the wellbore and the auxiliary fluid inlet temperature is controlled to be less than 20 °C, the circulating mode B has the best temperature-controlled effect. Therefore, the circulating mode B of reelwell drilling method can provide a new option for temperature-controlled drilling for the deep closed-loop geothermal system.

A comparison between conventional blast hole sampling and diamond core drilling for copper grade at the Antapaccay mine

Even though the sampling technique result in potentially biased samples with poor precision of the metal grade and are classified as specimens and not samples, the manual sampling of rotary percussion blast hole chips is still widely performed in the industry for operational grade control purposes. The objectives of this investigation are to estimate the precision and“bias” of manual sampling by comparing the copper grade results of fifteen (15) diamond drill core samples versus fifteen (15) rotary percussion blast hole drilling chip samples. This also includes the determination of a practical manual sampling template with the highest precision to providean understanding of the distribution of the copper content within the cone of blast hole chips. The contouring plots of thecopper grades provides the selection of the best fit-for-purpose template with regards precision and operational resourcing requirements. The diamond drill core samples take into account the Increment Delimitation Error (IDE) andIncrement Extraction Error (IEE) and therefore can be considered as reference samples for the purpose of this review.

Role of conventional drilling and abrasive water jet induced damage on the mechanical response of flax/epoxy laminates with holes

Many engineering applications using composite materials require an assembly of components which can be accomplished using adhesives, welding, or fasteners. The last requires the machining of holes, which are usually done via conventional drilling or abrasive water jet process. The choice of the machining process is important because it has a direct impact on the surface quality of the machined holes, and, consequently, on the performance of the composite structure. Although most studies on the effect of machining methods were focused on conventional composites, little is known about the effect of conventional drilling (CD) and Abrasive water jet (AWJ) machining methods on the mechanical behaviour of flax composites with holes. This study is the first to experimentally investigate the influence of the machining process in pure flax/epoxy composites with three different layups, namely, unidirectional (F[0]), cross-ply (F[0/90]) and angle-ply (F[±45]). A delamination factor was employed to evaluate the degree of delamination damage around the surface of the hole. The lowest delamination factor at the exit of the hole was observed for F[0]-AWJ with a value of 0.777 and the highest was observed for the F[±45]-AWJ with a value of 1.484. Damage analyses of the layups under a quasi-static loading condition showed that the average final stiffness damage for F[0]-CD was 13% greater than that of F[0]-AWJ, and for F[0/90]-AWJ and F[±45]-AWJ were respectively 25% and 27% greater than their counterpart samples machined by CD method. The damage results correlate well with the delamination factor.

Effect of the Implant Macro-Design on Primary Stability: A Randomized Clinical Trial

Aim of the study: Comparing the impact of two different implant macro-designs on the primary stability. Material and methods: Patients received implants in the lower posterior jaw (bone type II and III). Two different macro-design implants were inserted randomly in accordance with a conventional drilling protocol, the first one is the hybrid self-tapping implant: Straumann® bone level BL and the second one is tapered self-tapping implant: Straumann® bone level tapered BLT.16 implants (3.3 and 4.1 mm diameter, length between 8 and 10 mm) of each of the two above-mentioned implants were used. The assessment of the primary stability of each implant design was carried out by using two methods, recording the maximum insertion torque IT (DTA device) and recording the implant stability quotient ISQ using the resonance frequency analysis RFA (with the Osstell device). Results: Within the limitation of the present study, in all bone types, BLT implants showed significantly higher mean insertion torque IT when compared to BL with respectively 46.67±6.85 Ncm for BLT implants and 35.77±6.72 Ncm for BL implants (p=0.01 as per the Anova test), and higher mean ISQ with respectively 77.15±5.16 and 70.74±4.83. (p=0.01 as per the Anova test). Conclusion: In type II and III bone, the tapered self-tapping implant (Straumann® BLT) statistically showed better primary stability when compared to hybrid self-tapping implant: Straumann® bone level BL. Within the limitations of the present study, it can be concluded that the implant Macro-Design might be considered as a reliable parameter to achieve acceptable primary stability of dental implants in areas with low bone density. In the present study, the two methods used to assess the primary stability of the different macro-designs, torque assessment and the resonance frequency analysis RFA, showed a weak correlation. The macro-geometry is basically made to satisfy the needs in some critical bone situations and in immediate loading protocol.

Study on exit damage characteristics of ultrasonic vibration assisted drilling of CFRP

In order to solve the disadvantage of tearing and burr damage in axial drilling of carbon fiber reinforced plastics (CFRP), the stiffness at the exit is increased by applying different drilling speed in ultrasonic vibration assisted drilling (UVAD) Firstly, compared with conventional drilling (CD), ultrasonic assisted vibration drilling can realize the separation of axial tool and tool/chip; Secondly, the cutting speed characteristics of ultrasonic assisted drilling at different speeds are analyzed, and the change of cutting speed characteristics of ultrasonic assisted drilling at low speed is obvious; Finally, the change trend of contact rate at different speeds is analyzed. The experimental results show that the stiffness of ultrasonic assisted vibration drilling is significant. Taking the speed of n = 100 r/min as an example, the stiffness of ultrasonic assisted drilling is about twice as high as that of rotary speed n = 2400 r/min, which is about 8% higher than that of ordinary drilling when n = 100 r/min; Hole exit quality of low-speed drilling: compared with CD, the tearing factor of ultrasonic assisted vibration drilling is lower. Therefore, this method provides a way to improve the hole quality of CFRP.

Case Study: Not Just for Drilling: A Survey of the Application of Managed-Pressure Techniques

Every activity within a well alters the pressure being exerted on the open hole, and every mitigation technique attempts to maintain the desired pressure within acceptable limits. If the pressure becomes too low, kicks, borehole breakouts, and hole collapse are the primary consequences (Fig. 1). Pressure that is too high can damage the reservoir, induce fluid losses, and slow down operations. When these unfortunate events occur, remedial actions are usually necessary, increasing safety exposure, nonproductive time, and the overall costs of the project. To mitigate these concerns, operators have used the techniques of managed-pressure drilling (MPD) to maintain annular pressure and create a pressure-tight barrier against drilling hazards and manage inflow from the formation during drilling. While conventional drilling uses the hydrostatic pressure of the drilling mud to manage the pressure of the wellbore, MPD uses a combination of surface pressure, hydrostatic pressure, and annular friction to balance the exposed formation. Over the decades, MPD has been associated as a technology that is used only on problematic wells and only as a last resort. However, recent developments have highlighted that managing pressure is not just for drilling operations or just the most challenging wells. When integrated at the beginning of operations as part of a comprehensive well plan, managing pressure becomes a performance-enhancing solution for any type of well classification, including development, directional, multilaterals, and horizontals. Wellbore stability is maintained throughout the entire operation and pressure is dynamically altered in the annulus, enabling any operation to become faster with fewer challenges while delivering a more productive well and reducing overall costs and exposure to hazardous risks. The managed-pressure approach has even been leveraged to fully optimize a field/reservoir development program. An example of how MPD techniques can be incorporated into an overall well plan occurred on an ultradeepwater exploration well drilled by TotalEnergies in the Mexican waters of the Gulf of Mexico (SPE 200503). The operator and the service providers wanted to manage the pressure during the entire well program—including drilling, tripping, running casing, and cementing—to address pore pressure uncertainty, pressure ramp increase, and a narrow pore pressure/fracture gradient (PP/FG) window. The seafloor rested under 10,748 ft (3276 m) of water, and with the exploratory nature of the well, the conventional solution involved an excessive number of casing strings and an overbalanced mud weight (MW). Integrating MPD techniques enabled the operator to adjust the bottomhole pressure instantaneously, the result being a recognition that conventionally cementing a string of 13⅜ -in. casing to isolate the critical formation and safely continue drilling further stages of the well was impractical. To make the situation even more challenging, the engineers did not precisely know the size of the hole. A collaboration between the engineering teams of the operator, the cementing service provider, and MPD professionals resulted in a generated plan. A tail slurry of 15.86 ppg (1.90 SG) followed a 12.52 ppg (1.50 SG) lead gas-tight slurry. At a total depth of 13,622 ft (4152 m), the combination kept the equivalent circulating density (ECD) at 9.18 ppg (1.10 SG) without exceeding 9.51 ppg (1.14 SG). At the casing shoe, located at 12,801 ft (3902 m), the plan called for a 9.01 ppg (1.08 SG) without exceeding 9.35 ppg (1.12 SG), as shown in Fig. 2.

The Design and Development of a Tajweed Learning Innovation

e-Tajweed Yadun is a mobile application developed for learning the science of tajweed effortlessly and efficiently. The application can be simply downloaded and accessed anytime, anywhere. It involves a combination of multimedia and creative graphic elements of a ‘Yadun’ model which is an Arabic term for ‘hand’. e-Tajweed Yadun aims to create an interactive self-learning environment for deeper understanding and memorization of specific tajweed laws that could be burdensome when learned via books and conventional drills. The development of e-Tajweed Yadun involved five phases, namely theoretical study and needs analysis, model development, prototype design, prototype development and evaluation. e-Tajweed Yadun is a new alternative technique to learn the science of tajweed, particularly for Muslim students, as a guide while reading the Qur’an.
 Keywords: e-Tajweed, Yadun, application, innovation

FIB-DIC Residual Stress Evaluation in Shot Peened VT6 Alloy Validated by X-ray Diffraction and Laser Speckle Interferometry.

Ga-ion micro-ring-core FIB-DIC evaluation of residual stresses in shot peened VT6 (Ti-6Al-4V) alloy was carried out and cross-validated against other non-destructive and semi-destructive residual stresses evaluation techniques, namely, the conventional X-ray diffraction and mechanical hole drilling. The Korsunsky FIB-DIC method of Ga-ion beam micro-ring-core milling within FIB-SEM with Digital Image Correlation (DIC) deformation analysis delivered spatial resolution down to a few micrometers, while the mechanical drilling of circular holes of ~2 mm diameter with laser speckle interferometry monitoring of strains gave a rough spatial resolution of a few millimeters. Good agreement was also found with the X-ray diffraction estimates of residual stress variation profiles as a function of depth. These results demonstrate that FIB-DIC provides rich information down to the micron scale, it also allows reliable estimation of macro-scale residual stresses.

Towards understanding the hole making performance and chip formation mechanism of thermoplastic carbon fibre/polyetherketoneketone composite

Here, we report the first study on the hole making performance of thermoplastic carbon fibre/polyetherketoneketone (CF/PEKK) composite. Different hole making methods (conventional drilling vs. helical milling) have been compared and the effect of different feed rates has been investigated. The effect of thermal-mechanical interaction on the resulting hole damage has been elucidated for the first time for carbon fibre reinforced thermoplastics (CFRTPs) hole making. In the material science dimension, advanced material characterization techniques have been deployed to reveal the material removal mechanisms at microscopic scale and unveil the underlying material structural change at a molecular level. Results show that the delamination damage of CF/PEKK is a result of the thermal-mechanical interaction. For conventional drilling, the high machining temperature (at low feed rate <0.1 mm/rev) has a stronger influence on the delamination damage and the delamination starts to show stronger dependence on the thrust force at high feed rate >0.1 mm/rev. In contrast, helical milling generates a much higher machining temperature which plays a more predominant role in the associated delamination damage. Microstructural analysis shows that all the hole surfaces feature matrix smearing, as a result of combined in-plane shear stress and high machining temperature. Conventional drilling leads to more severe hole wall microstructural damage (matrix loss and surface cavity) as compared to helical milling. Finally, thermal analysis reveals that the hole making process has led to significantly increased crystallinity in the PEKK matrix as a result of the strain-induced crystallization under the combined effect of shear stress and high temperature. • Hole making performance of CF/PEKK is investigated for the first time. • A comparative study on conventional drilling and helical milling is reported. • The role of thermo-mechanical interaction is elucidated for CF/PEKK hole making. • Chip morphology and the associated material removal mechanism are revealed. • Shear-induced crystallization caused by hole making is reported for the first time.

Study on the Simulation and Experiment of Ultrasonic-assisted Vibration Drilling of Ti6Al4V

Titanium alloy is a typical difficult-to-cut material used in most industrial fields, so its machinability is characterized by low efficiency and poor quality using Conventional Drilling (CD). To address this issue in drilling workpiece of Ti6Al4V the ultrasonic vibration with high-frequency and low-amplitude is applied in the feeding direction of drill bit. Based on Johnson-cook constitutive model of workpiece material, a 3D FEM cutting simulation is conducted to analyse the variation trend of thrust force and the formation of hole burr under different processing parameters. The simulation and experimental results demonstrate that the ultrasonic vibration can convert continuous cutting into periodical intermittent cutting, which is helpful to break chip and deburr as well as enhance inner wall quality of hole significantly. Moreover, ultrasonic assisted drilling decreases the thrust force, improves the rigidity of the cutting tool in the process of drilling and facilitates removing the workpiece material. Therefore, the ultrasonic vibration can effectively promote the drilling quality of titanium alloys Ti6Al4V compared with CD.

ΟSSEODENSIFICATION. A PROMISING NEW TECHNIQUE.

INTRODUCTION: The technique of Οsseodensification has recently appeared in clinical practice by Salah Huwais for the placement of dental implants. This technique relies on the use of special burs (Versah), which in contrast to the conventional drilling techniques these burs do not excavate bone. PURPOSE: To highlight the importance of Οsseodensification in clinical practice. METHOD: A literature review for the last five years was performed, with keywords such as: Implant stability, osseodensification, osteotomy. RESULTS: During osteotomy, unlike conventional implant drills, the bone is advanced into the implant shaft instead of being removed. Versah burs allow for more accurate osteotomy preparation and reduce any potential drilling vibrations. With these special burs we have the ability to push the bone towards the base of the implant lumen. Finally, a closed sinus lift can be achieved by lifting the sinus membrane up to 3 mm without the use of a foreign graft. CONCLUSIONS: Οsseodensification has helped the clinician to achieve the maximum possible primary stability during the placement of the implant. The fact is, however, that there is a lack of sufficient documentation. It is therefore necessary to carry out more clinical studies, so as to lead to safer conclusions about the long-term results of the above technique.

Microleakage Evaluation of Glass Hybrid Restoration Following Usage of Papain-Based Gel and Ceramic Bur for Caries Removal

Introduction: In the field of pediatric dentistry, an urge to adopt a more comfortable, minimally invasive, and stressless technique for caries removal became a must. Coronavirus disease-2019 outbreak necessitates a paradigm change in the global health care protocols, requiring alternative, nonaerosol generating approaches. This study aimed to measure and compare the influence of two methods of caries removal, namely, Brix3000 and CeraBur, on the microleakage of glass hybrid restorative material. Materials and Methods: Thirty human primary molar teeth with accessible occluso-gingival carious cavitation were randomly allocated into CeraBur and Brix3000 groups. After selective caries excavation, samples were restored with Equia Forte HT, thermocycled, dipped in thiazine dye, washed, and sectioned through the restoration center. Then microleakage was measured using a stereomicroscope (30× magnification) at both occlusal and gingival margins. Results: No statistically significant difference was found between the two methods of caries removal (CeraBur and Brix3000) at both occlusal (P = 1.000) and gingival margins (P = 0.612). Conclusions: Brix3000 caries removing gel did not negatively affect the microleakage of Equia Forte HT compared to the CeraBur and hence can be used alternatively to the conventional drilling methods.

Wellsite Real-Time Geochemical and Petrophysical Logging in North America Unconventionals

Hundreds of wells are drilled in North America each year targeting the unconventional resource-rich oil and gas reservoirs across various basins. Each unconventional reservoir has unique and distinct petrophysical and geochemical properties based on reservoir geology and the geological environment of deposition. Unlike conventional drilling and completions, for unconvention-als, traditional logging and evaluation methodologies leave a lot of uncertainities and inconclusive answers to challenging reservoir heterogenities in providing inputs to target selection, well placement, completions and predict production potential. There are various techniques from surface logging methodologies to achieve quantitative results and interpretations. These techniques are non-intrusive and have provided some important and conclusive interpretation in recent years. This article will highlight key formation evaluation techniques that aided operators to drill and complete wells in the Wolfcamp, Bone Spring, Avalon, Spraberry, Woodford, Meramec, Osage, Haynesville, Marcellus, San Andres and Yeso formations.

Investigating hole making performance of Al 2024-T3/Ti-6Al-4V alloy stacks: A comparative study of conventional drilling, peck drilling and helical milling

This work reports a comparative study on different hole making methods, namely conventional drilling, peck drilling and helical milling, for Al 2024-T3/Ti-6Al-4V stacks in aircraft applications. The impacts of different hole making methods with constant or varied machining parameters across the stacked structures have been investigated. The resulting exit burr, hole surface roughness/microstructural change and fatigue behaviour of the machined stacks have been characterized in detail. Results show that the exit burr formation is most severe for conventional drilling and least burr is produced in helical milling coupons. Deploying varying parameters (i.e. optimal parameters for each individual metal layer) across the stacks can effectively reduce the burr formation in conventional drilling and peck drilling. 3D surface morphology shows that Al 2024-T3 hole surface contains multiple scratches and trenches, while Ti-6Al-4V hole surface features regular feed marks. Helical milling leads to the highest Al 2024-T3 hole surface roughness, which can be attributed to the abrasion caused by the evacuated Ti-6Al-4V chips. Sub-surface microstructural analysis shows that the Ti-6Al-4V layer is more prone to machining-induced microstructural change (i.e. white layer formation and/or grain plastic deformation along machining direction). The relatively low fatigue performance of stacks produced by conventional drilling and peck drilling with constant parameters can be related to the presence of the brittle Ti-6Al-4V white layer in these coupons. Deploying varied parameters across stacks in conventional drilling and peck drilling can effectively eliminate Ti-6Al-4V white layer formation and improve the stacks fatigue life by 72% and 38%, respectively. Helical milling leads to the longest stack fatigue life (~ 100% and 40% greater than conventional drilling and peck drilling, respectively).