Types Of Bits Research Articles

Research and analysis of rock breaking mechanical model of single-roller PDC compound bit

In order to improve wear resistance and rock breaking efficiency of single-roller bit, a new type of bit, single-roller PDC compound bit is designed. The mechanical model of interaction between PDC teeth and rock of single-roller PDC compound bit is established, and the theoretical calculation formula of resultant force and torque generated by interaction between PDC teeth and rock on cone and bit is obtained. The rock-breaking experiment on the single-roller PDC compound bit are carried out. The results show that with the increase of front inclination angle, the axial force and radial force of PDC teeth decrease greatly at first and then tend to be stable, while the tangential force of PDC teeth decreases at first and then increases slightly; the axial force, radial force and tangential force all increase with the increase of the cutting depth; the maximum values of the three forces all appear at the position of the combined effect of the maximum cutting depth and the minimum front inclination angle. The maximum value of moment [Formula: see text] and [Formula: see text] both appear at the minimum value of h C and δ, while the maximum value of moment [Formula: see text] appears at the minimum value of δ. In order to reduce the acting moment generated by PDC cutter on the roller, the PDC cutter at different position heights can be designed with different front inclination angles. The rock breaking experiment results show that compared with the common single-roller bit, the single-roller PDC compound bit has higher rock breaking efficiency and better development prospect. When drilling in hard limestone, the single-roller PDC compound bit is more energy-efficient under higher WOB.

Fabricating diamond bit by selective laser melting and its drilling performance evaluation

Diamond abrasive tools play an important role in efficient and precision machining of difficult-to-cut materials. As the traditional tool manufacturing process is difficult to meet the integrated molding preparation of complex structures, the use of selective laser melting (SLM) technology to manufacture diamond tools with functions and structures has become a research hotspot in recent years. In this paper, the feasibility and wear characteristics of diamond bits prepared by SLM using AlSi7Mg as metal matrix are investigated. The optimal parameter combination of diamond/AlSi7Mg mixture was obtained through orthogonal experiments, in which the powder layer thickness was 30 μm, the laser power was 300 W, the scanning speed was 3000 mm/s, and the scanning spacing was 120 μm. This parameter combination realized the improvement of the mechanical properties and the decrease of the porosity. Two types of bits with and without groove-structure (Labeled as Bit-G and Bit-N) were fabricated and their drilling performance were compared by processing BK7 optical glass. The results show that the Bit-G has more excellent machining performance, including lower drilling force, better hole quality and longer service life. According to the simulation results, the self-sharpening cycle of the Bit-G’s wear characteristics can be attributed to the groove structure that allows the coolant to be fully utilized in the bit/workpiece contacting area. This paper demonstrates the feasibility of the SLM process for the preparation of diamond tools and comprehensively analyzes the wear process, which provides reference value for further research on this process for the manufacturing of diamond abrasive tools.

Working mechanism and experimental study of split bit

As a component directly acting on the rock in the drilling process, the low efficiency of rock breaking will occur when the bit is drilled. In this paper, a new type of split drill is designed in which the cutting ring can move relatively independently, as well as the kinematic analysis model of the cutting tooth is established. The displacement, velocity and acceleration values of the specific points on the cutting tooth ring of the bit are obtained, which verifies that the small cutting ring at the center of the split cone bit can improve the rock breaking efficiency at the center of the bit. Through the comparison experiments of different types of bits and split bits, the results show that the mechanical drilling rate of split single-tooth bits and triple-tooth bits increased by 11.7% and 12.4%, respectively, in Beipei limestone conditions. Meanwhile, the speed of those two increased by 8.9% and 11.4%, respectively, in Wusheng sandstone conditions, which effectively improved the rock-breaking performance. Combined with the results of bottom hole model, the characteristics of impact, invasion and cutting in the process of tooth rock breaking can be obtained, which effectively improves the rock breaking performance and verifies the rationality of bit design and the correctness of theoretical analysis.

Numerical Investigations for Rock-Breaking Process and Cutter Layout Optimization of a PDC Drill Bit with Dual-Cutter

PDC (polycrystalline diamond compact) drill bits are widely employed for rock-breaking in many industries like underground engineering and building constructions. The cutter layout would directly affect the overall performance of the drill bits. Field applications show that the staggered cutter layout strategy of dual-cutter can increase the drilling efficiency of the PDC bit. In order to explore the rock breaking mechanism of this type of drill bit, a numerical model of a dual-cutter and rock breaking with damage evolution based on a hybrid finite and cohesive element method (FCEM) has been established in this work. The model is verified through Brazilian disk tests. The rock breaking processes of this type of bit have been analyzed, including crack initiation, propagation, and the formation of rock debris. Moreover, the effects of horizontal and vertical offset of the back cutter on the MSE (mechanical special energy) have been investigated. Results demonstrate that the dual-cutter can prominently reduce the MSE compared to a single-cutter. The vertical offset of the back cutter has a minor effect on the MSE, while the horizontal offset is of great significance on the MSE. On this basis, the relationships between the MSE and both the vertical and horizontal offset coefficients have been built based on the response surface methodology (RSM). Finally, an optimized layout solution, with optimal vertical and horizontal offset coefficients of 0.641 and 0.497, is determined via the Gray Wolf algorithm.

Influence of blades’ shape and cutters’ arrangement of PDC drill bit on nonlinear vibration of deep drilling system

In this paper, the surface morphology method is improved and the bit-rock interaction model between the rock and the PDC bit is studied, considering the influence of blades’ shape and the cutters’ arrangement. Based on this model, the dynamic model of the deep drilling system equipped with arbitrary shape PDC bit is established, and the stability prediction method is proposed. Based on the improved surface morphology method, the dynamic characteristics of the drilling system equipped with four different types of bit (an actual bit, a Tian bit, a Tian bit with blades, and a traditional bit) are studied, comparing with the Tian model based on polygon clipping. The results indicate that the influence of blades’ shape and cutters’ arrangement of PDC bit on the nonlinear vibration of the drilling system cannot be ignored. By applying the proposed method, the dynamic model of the drilling system equipped with an actual PDC bit presents excellent computational efficiency, accuracy, and avoids unreasonable behavior, which provides a reliable theory for the dynamic analysis of the drilling system. In addition, the proposed uncut volume error and repeated cutting volume error can be used to evaluate the shape design of the drill bit and the accuracy of the bit-rock interaction model.

Bits and Cheek-Pieces from the Archaeological Sites of the Northern Altai of the Rouran Period (Based on the Materials of the Choburak-I Complex)

Purpose. This article studies bits and cheek-pieces belong to the mass categories of riding horse equipment from the archaeological sites of Altai of 2nd century BC – 5th century AD. These finds, taking into account the rarity of such materials from synchronous sites in adjacent territories, are an important source for the reconstruction of horse equipment of the nomads of Central and North Asia. The article presents the analysis of a series of bits and cheek-pieces from objects of the Rouran period of the Choburak-I necropolis.Methods and Results. The analyzed collection includes nine bits and five cheek-pieces. The basis of the study was the morphological analysis and classification of items of horse equipment, as well as the comparison of these finds with materials from neighboring territories. Two types of bits and two types of cheek-pieces are distinguished, demonstrating common and special features of the manufacture of bridle sets by the population of Northern Altai in the Rouran period. A comparative study made it possible to determine their dating and genesis.Conclusion. It has been established that bits and cheek-pieces are an important chronological marker for further clarification of the periodization of the archaeological sites of Altai. It is concluded that the horse equipment of the Bulan-Koby archaeological culture had a significant impact on the appearance of this category of objects among the early Turks. The results obtained expand the existing ideas about the evolution of horse equipment among the nomads of Asia in the middle of the 1st millennium AD.

The new design scheme of drilling rock cutting tools, working in rotation mode pairs

The article describes the dynamics of drill bits, drilling modes, distribution of resistance forces when drilling with bits. The theory of drilling a well of arbitrary shape, possible shapes of contacting figures at the bottom hole and the type of drill bit operating in the rotation pair mode are considered. This type of bit has the properties of a double center of rotation, which results in attrition drilling. At the same time, during drilling, the load on the bit will be located the same throughout the working part, it is also theoretically shown that the specific volumetric and contact work of the cutting parts will be the same, which leads to the same wear of the bit. It also discusses the issues of improving the flushing and blowing of wells when drilling with rotary steam bits.

Real Time Optimization of Drilling Operations and Performance Based on Drilling Specific Energy Determined from Actual Field Data

Drilling specific energy (DSE) is an important factor for improving the drilling performance after reaching the maximum energy that is necessary to remove and destroy the rock volume underneath the bit. Therefore, field data are used to optimize and analyze the drilling performance by combining between hydraulic data and mechanical data to obtain the maximum DSE on different types of bits used to drill the Colibași stratigraphic column. These bits are tricone and PDC. Furthermore, Two sections (17 1/2" and 12 1/4") are optimized based on DSE equation and the 8 1/2" hole section was optimized based on simulation analysis done by Landmark software. Well 268 drilling data are used to perform this study and verify the results. It was found that DSE from various equations with different parameters has reach the same results. Also, DSE shows higher values for lower ROP and vise verse, and three different hole conditions' zones. Additionally, the simulation study showed another bit optimization through determining the variation of bit power, impact forces, and pressure losses with various pumping rates.

Development of methodological and constructive foundations for drilling wells using new types of bits

Purpose. Improving the technical and economic indicators and the degree of perfection of the process of constructive selection, justification and engineering calculation of effective schemes for the implementation of individual units of drill bits, ensuring the constancy of the process of deepening the bottom hole with high productivity and resource saving. Research methodology. Applied computational and laboratory studies of the design features of the design choice of drilling bits of new designs were carried out using modern methods of analytical analysis and experimental research, in particular, by using the general principles of mathematical and physical modeling, methods for processing research results in the EXCEL, MATHCAD environment, control and measurement systems and materials. The flow of borehole processes was modeled on experimental wells of the training drilling site of the Dnipro University of Technology using the UKB-4P drilling rig and the corresponding auxiliary tools and equipment. Research results. A critical review of research and development in the field of designing drill bits was carried out; special attention is paid to the schemes for the implementation and operation of weapons systems and analysis of the properties of materials used to manufacture individual parts of drill bit assemblies; highlights the main advantages and disadvantages of existing schemes for the execution of bits; factors of working capacity and durability of elements of bits are defined; the causes of bit wear are established and the provisions of the problem of improving the technique and technology for making drill bit assemblies are formulated. Originality. A constructive approach to the drilling bit execution system using advanced technology and the creation of a workable destructive assembly of the specified tool for well construction can be based on the principle of chain execution of the destructive body. Practical implications. Fundamentally new design schemes for the implementation of the working destructive unit of the drill bit have been created, the use of which will lead to a significant increase in the productivity of exploration and production work, a reduction in the time for auxiliary operations, and an overall increase in the efficiency and economy of the well construction process.

О редких типах удил и псалий XI–XII вв. из Волжской Булгарии (к вопросу об этнокультурных контактах)

The article deals with rare types of medieval iron bits and cheek-pieces. They were found at the archaeological sites of the Volga Bulgaria of pre-Mongol times. Despite the fact that the material culture of the Volga Bulgaria has been studied for more than 100 years, the items of horse equipment have not been studied enough. The classification of the bits was made by F. Sh. Khuzin based on materials from the Bilyar hillfort and E. P. Kazakov based on finds in settlements located in the lower reaches of the Kama. However, we are considering bits that have no absolute analogues, both among the antiquities of the Volga Bulgaria, including those that were published, and neighboring territories. A comparative analysis showed that this type of bit is not found in the Bulgar burial grounds of the 8th- 10th centuries, as well as in the settlements of the 13th-14th centuries. Therefore, the date of their manufacture and use can be determined between the 11th and 12th centuries. The presence of characteristic details of decor suggests that the upper limit of their existence is the second half of the 11th century. The closest analogies to the considered artifacts are found in Southern Siberia. Details from horse headbands, which could have such bits, have also been studied. The author claims that the Bulgars in the 11th-12th centuries used two types of headband — with round disks with three holes as belt distributors and rings with three clips in the same capacity. As in the case of bits, the closest analogies to them are found in the materials of Southern Siberia.

Study on the Applicability of a New Type of Bit in Ordovician - Cambrian Dolomite Formation of Tarim Basin

The Ordovician-Cambrian reservoirs in Tarim basin are characterized by complex geological structure, deep reservoir, and thick dolomite strata in the middle and deep formation. The dolomite formation is characterized by large content of chert, high dense lithology, high uniaxial compressive strength, prominent impact and heterogeneity of the formation, it was difficult for conventional drill bits to form stable effective cutting depth and prone to vortex damage, which leads to short drill footage, low ROP and long drilling cycle, it seriously restricted the efficient exploration and development of Cambrian subsalt reservoirs in this block. Therefore, experimental analysis of rock mechanics in the Cambrian dolomite formation was carried out to quantitatively evaluate the rock mechanics properties in this area. A new type of PDC bit was designed to improve the impact resistance and eddy resistance of single teeth, and the impact fatigue test was carried out and successfully applied in the field. The research results show that compared with the adjacent wells in the same interval and lithology, the footage is increased by 39%, and the ROP is increased by 84%, which has achieved obvious acceleration effect, providing technical reference and support for the efficient exploration and development of Cambrian pre-salt reservoirs in the Tarim Basin.

Experimental research on working principle of the composite single-cone bit

The composite single-cone bit is a new structure of single-cone bit, which breaks the limitation of the one-piece cone structure of existing single-cone bit. The new bit structure makes it possible to apply PDC cutters with strong wear resistance to single cone bit. PDC cutter is more suitable for rock breaking by scraping. In this paper, rock breaking and comparative drilling experiments of composite single-cone bit are carried out. The experiments verified the working principle of the new composite bit. The effective combination of fixed and unfixed cutting structures in the new bit can form complex cross-scraping. The comparative drilling experiments show that the new composite bit has higher rock breaking efficiency than the common single-cone bit, and it is more energy-saving for cross-scraping. The application of PDC cutters can improve the wear resistance of bit cutters and prolong the service life of bit. The research results can provide basic support and reference for subsequent research on the design, development, and application of this new type of bit.

Optimization of the production plan of drill bits with fuzzy constraints based on a heuristic method

The problem of optimizing the production plan under fuzzy constraints is formulated using the theory of fuzzy sets. To solve the obtained fuzzy optimization problem, a heuristic method is proposed, in which, on the basis of the use of expert information and the knowledge of experts, the decision-maker in the optimization process and the choice of the best solution, it makes possible to improve the solution of the fuzzy problem. The results obtained are implemented and applied when solving the problem of optimizing the production plan of a plant for the production of diamond drill bits under fuzzy constraints. It is shown that when solving the optimization problem based on the proposed fuzzy approach, the plant’s profit from the sale of different types of bits increases to 8%.

Non-linear Axial Vibrations of Composite Drill Strings Considering Interaction of Roller Cone Bit and Polycrystalline Diamond Compact Bit with Rock

Due to the world increasing energy demands, optimizing the drilling system parameters such as the weight on bit (WOB), and the structure of drill string and bit, also vibrations and dynamic behavior of drill strings are of significant interest to researchers and energy industries. Specially, to overcome limitations of drilling operations in oil and gas industry, composite drill strings as high-tech devices are under development. In this research, the fully coupled non-linear axial vibrations of composite drill strings due to the interaction of two common bits namely; Roller Cone (RC) and Polycrystalline Diamond Compact (PDC) with rock, considering the major non-linear terms, the drill string-wellbore contact, the different weight on bit (WOB) and the different composite configurations using the finite element method (FEM) and the Lagrangian approach were studied. This study proved that the different configurations of composite drill strings showed specific dynamic behavior at different conditions. Therefore, composite drill string can be designed for particular purposes. Also, the results imply the remarkable effects of weight on bit (WOB) and type of bits on the axial vibrations of composite drill strings.

Modern concepts in approaches to determining individual position of media cutters in people with physiological types of bit

According to the results of studying cone-beam computed tomograms of the head of 147 people of the first period of adulthood with a full set of permanent teeth and physiological types of occlusion, the average inclinations of the incisors with respect to the occlusal plane and intercavity angles were calculated, and signs of a neutral position were formulated, physiological protrusion and physiological retrusion of incisors. It was revealed that the medial incisors of the upper jaw with the occlusal plane form an angle of 77.05 ± 0.70 degrees. For the neutral position of the incisors, the inclination angle varies from 75 to 80 degrees. A decrease in the incline angle of incisors in people with physiological types of occlusion of less than 75 degrees allowed the indicators to be considered as physiological protrusion, and an increase in the angle of more than 80 degrees characterized physiological retrusion. With the neutral position of the incisors, the intercavity angle averaged 135.49 ± 0.86 degrees. For the neutral position of the incisors, the value of the intersection angle varies from 125 to 145 degrees. The types of dental arches with the protrusive position of the incisors included variants in which the inter-incisal angle was less than 125 degrees. With the physiological retrusion of the incisors, the inter-incisal angle was more than 145 degrees. The results can be used as criteria for assessing the effectiveness of the treatment of patients with occlusion abnormalities.

Использование геофизических данных о пористости горных пород при выборе типов долот

Использование геофизических данных о пористости горных пород при выборе типов долот

ГРАФИЧЕСКИЙ МЕТОД ВЫБОРА БУРОВЫХ ДОЛОТ

Актуальность исследования обусловлена необходимостью выбора перспективных буровых долот на стадии проектирования технологии бурения. Это направление является ресурсосберегающим, минимизирующим объем промысловых испытаний при поиске оптимальных технологических решений. Цель: разработать уточненную методику выбора буровых долот по статистическим данным о показателях механических свойств горных пород. Объекты: идентификация буровых долот различных фирм и их выбор в соответствии со статистическими характеристиками механических свойств горных пород. Эти вопросы слабо изучены и вызывают затруднения при проектировании режимов бурения скважин. Методы: графоаналитическое изучение соответствия типов буровых долот прочностным характеристикам горных пород, определяемым методом одноосного сжатия и методом статического вдавливания штампа с плоским основанием. Результаты. Для идентификации долот различных изготовителей Международная ассоциация буровых подрядчиков (МАБП) разработала единую классификацию в кодах МАБП. Для отечественной практики возникла дилемма: горные породы охарактеризованы твердостью горных пород по штампу и в категориях, а долота – прочностью горных пород при одноосном сжатии и в кодах МАБП. Предложен переход к показателю прочности горных пород, выраженному в кодах МАБП долота. Это обеспечивает единство характеристик как для долот, так и для горных пород. Соответственно предложены номограммы для выбора долот по статистическим величинам прочности горных пород в кодах МАБП, рассчитанных с надежностью 0,95. Показано, что можно аналогично выбирать долота и при представлении твердости горных пород в категориях. В случае лопастных алмазно-твердосплавных долот их выбор распадается на два этапа: выбор типа вооружения в соответствии с прочностью горной породы в кодах или твердостью в категориях и расчет числа лопастей долота, которое зависит как от прочностных характеристик горной породы, так и от диаметра долота. Для упрощения выбора долот предложено характеризовать буримость выделяемых интервалов бурения не словесно (мягкие, средние и т. д.), а их статистическими характеристиками в кодах МАБП или в категориях буримости с заданной вероятностью.

МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ ДРОБЛЕНИЯ ГРУНТА И МНОГОФАЗНОГО ТЕЧЕНИЯ БУРОВОГО РАСТВОРА ПРИ БУРЕНИИ СКВАЖИН

The aim of the work is a mathematical modeling of the rock crushing during drilling and removal of the drilling cuttings (sludge) to the surface by drilling fluid. The process of rock destruction is described using the mathematical theory of fragmentation. The distribution of sludge particles in size and mass depends on such factors as the properties of the drilled rock, the rate of penetration, the type of bit, and the output power. After the formation of sludge, the process of its removal to the surface is modeled. The drilling fluid together with the rock particles is considered as a heterogeneous multiphase medium in which the carrier phase – the drilling fluid – is a non-Newtonian fluid. The flow of such a medium is described using a mixture model in the framework of the multi-fluid approach. This results in a system of nonlinear partial differential equations, for which a new closure relation is derived. To solve the system, the SIMPLE algorithm is used. As a result, the flow properties are studied with the inclusion of particles of various sizes. In particular, for particles of small size due to the action of plastic stresses in a non-Newtonian drilling fluid, an equilibrium mode arises in which the particles move with the drilling fluid without slipping. This is the fastest mode of delivery of sludge to the surface. The specific dimensions of such particles depend on the parameters of the drilling process. In particular, the appropriate size range can be adjusted by changing the parameters of the drilling fluid.

Application of Optimized Least Square Support Vector Machine and Genetic Programming for Accurate Estimation of Drilling Rate of Penetration

This article describes how the accurate estimation of the rate of penetration (ROP) is essential to minimize drilling costs. There are various factors influencing ROP such as formation rock, drilling fluid properties, wellbore geometry, type of bit, hydraulics, weight on bit, flow rate and bit rotation speed. This paper presents two novel methods based on least square support vector machine (LSSVM) and genetic programming (GP). Models are a function of depth, weight on bit, rotation speed, stand pipe pressure, flow rate, mud weight, bit rotational hours, plastic viscosity, yield point, 10 second gel strength, 10 minute gel strength, and fluid loss. Results show that LSSVM estimates 92% of field data with average absolute relative error of less than 6%. In addition, sensitivity analysis showed that factors of depth, weight on bit, stand pipe pressure, flow rate and bit rotation speed account for 93% of total variation of ROP. Finally, results indicate that LSSVM is superior over GP in terms of average relative error, average absolute relative error, root mean square error, and the coefficient of determination.

Study on Bionic Diamond Bits for Drilling Superhard Materials

With diamond particles, metal powders and a special soft material as raw materials, this paper introduced some diamond bits to drill the superhard materials such as granite. Besides, the biology non-smooth theory was applied to the design of bit, and a new type of bit which is called bionic bit was introduced about its principle and manufacturing method. HYPERLINK "http://dict.cnki.net/dict_result.aspx?searchword=%e6%95%b0%e5%80%bc%e6%a8%a1%e6%8b%9f&tjType=sentence&style=&t=numerical+simulation" Numerical simulations and field tests of bionic bits showed that the optimalizing non-smooth degree was the most important factor of the design of bionic bit. By ANSYS finite element calculation when the non-smooth degree is 12.6%, the drilling bit wear is the smallest, 63% less than the ordinary bit. This paper prepared four bionic bits with the non-smooth degree 13% and four ordinary bits to drill the granit in gold mine, the average life and drilling speed of bionic bits increased by 29.8% and 21.3% more than ordinary bits.