The Wear and Friction Characters of Polycrystalline Diamond Under Wetting Conditions

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Chun Liu ◽  
Zhongyi Man ◽  
Fubao Zhou ◽  
Kai Chen ◽  
Haiyang Yu

Polycrystalline diamond compacts (PDCs) are the main cutting unit of drill bits and are a major factor in determining the drilling efficiency and service life of drill bits. Drill bit failure is caused by the severe abrasive wear it undergoes during the drilling process. The drill bit failure can prolong the drilling period, which can result in borehole instability and cause collapse in the material. A solution that can address this issue is developing an appropriate drilling method that can expel the dust in a manner that will not increase the abrasive wear on the drill bit. Here, an Amsler friction and wear-testing machines was used to investigate the friction and wear characteristics of PDC and to study the effects of the dust expelled during drilling on the wear performance of drill bits under dry air and wetting conditions. The microstructures of the worn surfaces were examined by a scanning electron microscope (SEM) and metalloscope. In addition, the chemical compositions of the PDCs' surfaces were analyzed using X-ray diffraction (XRD) after the wear and friction tests. The results demonstrate that the friction coefficients and wear rate obtained in dry air were higher than those under wetting conditions. As expected, these values are mainly ascribed to the absence of the absorber layer and lubrication under dry air. Furthermore, under wetting conditions a number of cracks were observed on the PDC surface after testing at 700 °C, which was mainly caused by two factors: The different thermal expansion coefficients between the diamond and Cobalt phase; and the residual stress generated inside the PDC under wetting conditions.

2021 ◽  
pp. 152808372110620
Author(s):  
AR Ngah ◽  
Suhad D Salman ◽  
Z Leman ◽  
SM Sapuan ◽  
MFM Alkbir ◽  
...  

Drilling is a secondary material removal and usually carried out to facilitate fastening of parts together. Drilling of composite materials is not usually a problem-free process. Issues related to delamination composite laminates need to be addressed because it introduces the stress concentration point on the composite. This study focussed on the influence of process parameters such as spindle speed, feed rate, type of drill bits and geometry on the extend of delamination experienced by the composite during the drilling process of kenaf-glass fibre-reinforced unsaturated polyester composite, and the delamination measurements were taken under a microscope. Taguchi methods and analysis of variance were employed to find the optimal parameters. From the results, the most significant parameter was the feed rate. The minimum delamination was achieved when the feed rate was 0.05 mm/rev and spindle speed was 700r/min using both types of drill bits. The quality of the drill hole using the twist drill bit has been proven to be better than the brad drill bit.


Tribologia ◽  
2018 ◽  
Vol 278 (2) ◽  
pp. 13-19 ◽  
Author(s):  
Rafał DUDEK ◽  
Krzysztof WŁADZIELCZYK

The article presents the results of the wear testing of buttons in selected types of bits with the diameter of 95 mm used for blast hole drilling in a rock mining. The purpose of the testing was to determine the type of the wear of peripheral and frontal buttons in the actual operating conditions of bits and the impact of selected parameters of the drilling process and of sharpening the buttons on their durability. Tests of button wear were carried out by the blasthole drilling in deposits of the Devonian and Triassic dolomites. For the blast hole drilling with tested bits, drilling rigs HSB 500 and HBM 60, equipped with down-the-hole impact mechanisms VKP 95-2 from the company Permon were used. Tests on the wear of buttons were carried out according to the adopted methodology, taking into account both their abrasive wear and wear through crushing or falling out. During the drilling of holes, every effort was made to use fixed values of parameters of the drilling process, except for the value of drill stem rotation speed, because one of objectives of the research was to determine its impact on the abrasive wear of tested bits buttons. The obtained results of tests proved that the predominant type of wear of button bits for blast hole drilling is an abrasive wear of frontal buttons, and regular sharpening of the buttons allows increasing the operating time of rock bits by up to 35%.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jinrong Chai ◽  
Zihao Zhou ◽  
Cheng Ye ◽  
Chen Yao ◽  
Guohua Li

AbstractSerious wear phenomena occur in mining machinery under complex working conditions, and the wear of machine parts is primarily caused by the synergistic effect of adhesive wear, abrasive wear, corrosive wear, etc. However, the existing friction and wear testing equipment cannot be used to carry out wear tests under complex working conditions. To simultaneously meet the test requirements of adhesive wear, abrasive wear, and corrosive wear, a novel sliding friction and wear tester that can simulate complex working conditions was developed in the present research. The tester is composed of a loading mechanism, a speed-regulating mechanism, a corrosion chamber, and a control and display system. Wear tests of the middle plate of a scraper conveyor, a key equipment of coal mining, were carried out to verify the consistency and effectiveness of the tester. The test results were consistent, and those under the same test conditions were similar with a maximum standard deviation of 2.4 mg. The wear condition of the middle plate specimens was close to the actual wear condition of the middle plate. Moreover, the surfaces of the middle plate specimens after grinding exhibited obvious adhesive, abrasive, and corrosive wear characteristics, and the wear degrees of the specimens under the same test conditions were similar. The quality loss of the middle plate specimens was found to increase with the increase of coal gangue percentage, and the main wear mechanism was the synergistic action of abrasive, adhesive, and corrosive wear.


2020 ◽  
Vol 103 (3) ◽  
pp. 003685042093097
Author(s):  
Dou Xie ◽  
Zhiqiang Huang ◽  
Yuqi Yan ◽  
Yachao Ma ◽  
Yuan Yuan

Polycrystalline diamond compact bits have been widely used in the Oil and Gas drilling industry, despite the fact that they may introduce undesired vibration into the drilling process, for example, stick-slip and bit bounce, which accelerate the failure rate and lead to higher drilling costs. First, we develop an innovative ridge-ladder-shaped polycrystalline diamond compact cutter, which has ridge-shaped cutting faces and multiple cutting edges with stepped distribution, in the hope of reducing vibration and improving drilling speed. Then, the scrape tests of ridge-ladder-shaped and general polycrystalline diamond compact cutters are carried out in a laboratory, indicating that the cutting, lateral, and longitudinal forces on ridge-ladder-shaped polycrystalline diamond compact cutters are smaller and with minor fluctuations. Due to different rock-breaking mechanisms, ridge-ladder-shaped polycrystalline diamond compact cutters have higher cutting efficiency compared to general polycrystalline diamond compact cutters, which is also verified experimentally. Finally, the drilling characteristics of a new polycrystalline diamond compact bit fitted with some ridge-ladder-shaped polycrystalline diamond compact cutters are compared to those of a general polycrystalline diamond compact bit by means of finite element simulation. The results show that introducing ridge-ladder-shaped polycrystalline diamond compact cutters can not only reduce the stick-slip vibration, bit bounce, and backward rotation of drill bits effectively, but also improve their rate of penetration.


2021 ◽  
Author(s):  
Syed Zahoor Ullah ◽  
Alexey Ruzhnikov ◽  
Syed Siddik ◽  
Maxim Sizov ◽  
Abdulqawi Alfakih

Abstract Drilling rate of penetration (ROP) is one of the variables that influences well delivery timing and cost. ROP is affected by many factors, including but not limited to rock strength, well profile, bottom hole assembly (BHA) design, challenging formations per section, and drill bit selection. In one of the drilling projects in the Middle East, the primary method chosen to improve well delivery is to focus on optimizing the drill bit design to improve ROP while delivering other drilling objectives. As the project progressed, the ROP plateaued in most of sections in the field. The drilling team collaborated with the drill bit engineering to launch a drill bit optimization campaign in various hole sizes ranging from 16-in to 6⅛-in. Since fixed-cutter bits are predominantly used in these sections, improvements are made to the existing drill bit designs by replacing the cutting elements with more efficient 3D polycrystalline diamond compact (PDC) cutters or 3DC. 3DC cutters have different shapes, uniquely designed to tackle different drilling challenges. Using an in-house petrophysical log analysis program, each formation drilled in this field was analyzed and drilling challenges and ROP values were compared against previous performance. This information paired with finite element analysis (FEA) for dynamic drilling simulation was used to optimize drill bit selection. This conceptual workflow was followed to avoid costly field tests and ensure that the newly designed drill bit performs flawlessly downhole. Other design elements, such as choosing bit body material, were also incorporated by converting matrix-bodied to steel-bodied, which not only improved the ROP but also reduced the cost-per-foot (CPF). Initially the bit optimization program enabled ROP improvement in the 16-in section by 36% from 53 ft/h to 73 ft/h by replacing the roller-cone bit with a matrix-bodied fixed-cutter bit. Moreover, the drilling team further improved their performance, achieving 118 ft/hr. ROP when using the steel-bodied bit. With successful deployment of 3DC cutters in Middle East, ridged diamond element was introduced in the 8½-in section and successfully improved overall ROP by 11%. In addition, the 6⅛-in section showed 25% improvement in ROP following several design iterations that utilized two different types of 3DC cutters. By the end of the drill bit optimization campaign, the operator was able to improve the drilling curve and save up to 2.5 days per well. The 3DC cutters also helped eliminate the risk of bit failure in the 8½-in section, wherein offset wells several bits were required to complete the section. With the performance mindset, new technology deployment made it faster to test new bit designs. This helped with getting early data point for analysis before being able to test in the different fields in the area.


2020 ◽  
Vol 8 (6) ◽  
pp. 2057-2060

In Belayim Oil field, Sidri concession, 8 1/2" section is composed of conglomerates with overall Unconfined Compressive Strength (UCS) varies from 25,000 to 40,000 psi. This section was mainly drilled with Polycrystalline Diamond Compact (PDC) bits and Tungsten Carbide Insert (TCI) drill bits. Drilling 1000 meter in 8 1/2" section needed minimum 6 to 8 drill bits. The average rate of penetration (ROP) was 2.8 (meter per hour) MPH and the average drilled interval was 135 m. The rock bit that had been used in offset wells achieved low ROP and short drilled intervals as well, meanwhile, PDC bit achieved moderate average ROP and relatively short run intervals The operator target was to reduce the drilling time by raising ROP and the drilled interval per drill bit; the hybrid bit was presented to achieve that target. The hybrid bit achieved the highest ROP record and the longest drilled interval in Sidri concession achieving 200 percent improvement from offsets’ average performance. Finally, the paper recommended using three hybrid bit in the first three runs and in the fourth run, where the unconfined compressive strength reached its maximum values, TCI drill bit could be used.


2014 ◽  
Vol 607 ◽  
pp. 153-160 ◽  
Author(s):  
A.M. Abdul-Rani ◽  
M.Zamri Ismail ◽  
M.Ariff Zaky ◽  
M.Hariz M. Noor ◽  
Y.Y. Zhun ◽  
...  

In petroleum industry, drilling is one of the most important aspects due to its economics. Reduction in drilling time is desired to minimize operations cost. This work focus on Polycrystalline Diamond Compact (PDC) drill bit which is categorized as a fixed cutter drilling bit. Problem such as wear and tear of PDC cutter are some of the main factors in drilling process failure affecting the rate of penetration (RoP). Thus, an intensive study in drill bit design could potentially save costs if the drill bit efficiency can be improved. The objective of this research is to improve the PDC cutter design and analyse design improvement in relation to the rate of penetration using reverse engineering (RE) approach. RE method is capable of resolving unavailable drill bit blueprint from the manufacturer due to propriety and confidential. RE non-contact data acquisition device, 3D laser scanner will be used to obtain cloud data of the existing worn drill bit. Computer Aided Design (CAD) software is used to convert cloud data of the PDC drill bit into 3D CAD model. Optimization of PDC Drill bit is focused on feature design such as back rake angle, side rake angle and number of cutters. CAE software is used to analyse the effect of the design feature modification to rate of penetration. Results show rate of penetration increases as the angle of both rake angle and number of cutter decreases.


2020 ◽  
Vol 17 (2) ◽  
pp. 34-37
Author(s):  
Oegik Soegihardjo ◽  
Samuel Trinata

The drilling process of an oil well uses a drill bit to drill a hole to drain crude oil from the bowels of the earth to the ground. Tool wear occurs in every cutting or drilling process that uses tool bits. A drill bit is the general term for the tool blade used in the drilling process. Two types of tool bits that are commonly used are roller cone and Polycrystalline Diamond Carbide drill bit or PDC. The case being study is the wear out of the PDC drill bit, that causing unplanned bit trip. This research was conducted as an effort to reduce the wear that occurs on the PDC drill bit. The aim of the research is to simulate the changes of the back rake angle, so that the impact of the back rake angle's changes on the wear of the drill bit could be investigated. The results of the simulations were compared with the tool wear data that occurred at one of the oil drilling locations.  


Author(s):  
D.I. Potter ◽  
M. Ahmed ◽  
K. Ruffing

Ion implantation, used extensively for the past decade in fabricating semiconductor devices, now provides a unique means for altering the near-surface chemical compositions and microstructures of metals. These alterations often significantly improve physical properties that depend on the surface of the material; for example, catalysis, corrosion, oxidation, hardness, friction and wear. Frequently the mechanisms causing these beneficial alterations and property changes remain obscure and much of the current research in the area of ion implantation metallurgy is aimed at identifying such mechanisms. Investigators thus confront two immediate questions: To what extent is the chemical composition changed by implantation? What is the resulting microstructure? These two questions can be investigated very fruitfully with analytical electron microscopy (AEM), as described below.


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