Roller Cone Research Articles

Tracking prevention in roller cone bit drilling

Tracking prevention in roller cone bit drilling

Evaluating PDC bit-rock interaction models to investigate torsional vibrations in geothermal drilling

Polycrystalline diamond compact (PDC) bits are superior for drilling geothermal wells because of their superior drilling performance compared to conventional roller cone bits. However, the shear action of PDC bits generates detrimental vibrations during drilling. The main objective of this study was to establish a methodology to analyze and predict the stick-slip severity in hard rocks for geothermal wells. Two non-linear coupled axial-torsional bit-rock interaction (BRI) models are presented: one is based on a velocity-decaying friction model (VDF), and the other is based on a state-dependent delay friction model (SDDF). The capabilities of the two models were evaluated to assess the axial and torsional dynamic stabilities of drill stems in deep geothermal wells. The comparative analysis, along with the results from both models, were validated using geothermal well downhole data. Five distinct zones were selected for analysis, and the stick-slip severity value (SSV) was calculated using these two models (VDF and SDDF). The results from these two models for the five different zones were compared with the field data. The results indicated that VDF demonstrated superior quality when compared with field values, as the results of VDF were within the interquartile range of the observed SSV in each zone. A sensitivity analysis employing spider plots was performed for both models, considering parameters related to rock, bit, operational, and frictional aspects. In terms of the operational parameters, the weight-on-bit (WOB) and revolutions per minute (RPM) exerted the most significant influence on the SSV for both models. For the VDF model, the sensitivity analysis indicated that the frictional parameter, uniaxial compressive strength (UCS), and number of cutters (NOC) had the most pronounced impact on the SSV. In the case of the SDDF, the Intrinsic specific energy (ISE), bit diameter, and number of blades (NOB) are the key factors that predominantly affect the SSV.

SUBSTANTIATION OF SOLUTIONS TO INCREASE THE DURABILITY OF THE INNER ROWS OF STEEL TEETH OF ROLLER CONE BITS DURING DRILLING OF BOULDER-PEBBLE ROCK FORMATIONS

The article deals with issues concerning the increase in the productivity of roller bits when drilling soft and soft-medium rocks with inclusions of boulder-pebble formations by justifying solutions to increase the relative safety margin of steel teeth expressed in an increase of the impact strength of the material for making cones in combination with an increase in the geometry of steel teeth. The efficiency of the rock-crushing tool and, as a result, the destruction of rock during the entire drilling cycle, directly depends on the resource and durability of the elements of the roller bit. When drilling the upper intervals of deposits in the East Siberian region, composed of soft and soft-medium rocks with inclusions of boulder-pebble deposits, there is a problem of premature wear of the drill bit. Both PDC bits are subject to catastrophic wear due to chips and fractures of PDC cutters, as well as roller bits. The use of first-class roller bits with steel teeth leads to advanced wear, expressed by the scrapping of the teeth of the inner rows. This leads to a «hanging» of the bit and a loss of mechanical penetration speed. Based on this, the work provides recommendations for increasing the durability of steel teeth for first-class roller cone bits.

Ways to Optimize the Kinetic Parameters of Tricone Drill Bits

The improvement of the operation of roller cone bits, only drilling indicators are optimized, which include axial load, frequency of rotation, borehole diameter and rock fortress coefficient. The use of one or another roller bit can be justified by the physical-mechanical properties of rocks, which can have different values depending on the depth of drilling and the horizon. However, while resolving energy costs on the basis of the quality of the drill bits’ interaction with the physical-mechanical properties of rocks and the condition of the cutters at the bottom of the well, which require high-tech solutions with scientific bases, it is possible to make the choice and justify a more efficient design of the drill bit. The article discusses a new method for determining the patency of a drilling cone bit using the determination of the workload of teeth and crowns based on kinematic calculations. Based on the kinematic parameters, the gear ratio of the cones, the specific indicators of contact and operation of the teeth on the bit crowns are determined, which in turn show the most loaded crowns. Based on these indicators, it is possible to determine crowns that are prone to breakage during the operation of bits. By this calculation was made a new program which by geometrical parameters of the tricone drill bit can show graphics of the work cones and crowns.

Consideration of the reasons for decommissioning of roller cone bits

Consideration of the reasons for decommissioning of roller cone bits

Design features of drilling equipment elements using materials with shape memory effect

Alloys exhibiting thermoelastic phase transformations are getting more and more used in different industries. This is due to the shape memory effect and pseudo-elasticity (sometimes termed “superelasticity”) they exhibit, which can considerably improve the performance characteristics of various technical systems. One of the highest reliability and durability criterias are applied to equipment for drilling oil and gas wells, and according to this the above-described smart materials and the phenomena they exhibit have been gradually implemented in the oil and gas industry. This article analyzes the developed design of roller cone bits elements and proposes its assembly method, and presents its comparison with currently existing designs. Computational research and computer analysis of a drilling equipment assembly containing parts made of shape memory materials were performed, these studies showed significant advantages of the proposed method.

Multi-Field Coupling Numerical Analysis and Experimental Validation of Surface-Textured Metal Seals in Roller Cone Bits

Metal seals play a crucial role in ensuring the dependable functioning of the bearing system in roller cone bits. Due to the intricate nature of downhole conditions, the microstructure design of sealing end faces, specifically the surface texture, is rarely used in metal seals. This study focuses on examining the applicability of surface texture technology in metal seals for cone bits to enhance the lubrication characteristics and friction and wear properties of liquid film between end faces. A multi-field coupling model of surface-textured metal seals was established and experimentally verified. The liquid film carrying the capacity and sealing performance of five different shapes of surface-textured end faces (circle, ellipse I (horizontal), ellipse II (vertical), triangle, and chevron) were investigated under varying rotational speeds and environmental pressures. The influences of texture parameters, including depth and area ratio, on the lubrication characteristics and friction reduction effects of surface-textured metal seals were investigated, and the microscopic wear morphology characteristics of the sealing end faces were analyzed. The results show that surface textures can effectively improve the liquid film state and comprehensive performance of metal seals. Specifically, triangle textures significantly enhance the hydrodynamic pressure effect and weaken the abrasive wear and adhesive wear of the end faces. However, when the environmental pressure is p ≥ 30 MPa, the surface textures gradually lose the advantages of dynamic lubrication but can still reduce friction. The proper texture depth and area ratio can achieve zero leakage (obtained theoretically) and minimal friction in metal seals.

Applicability of roller cone bits for drilling through interbedded rocks

Applicability of roller cone bits for drilling through interbedded rocks

Identification of resistance torque on the roller cone bit in the drill rod rotation drive

There is a problem of increasing the durability of the roller cone bit of the drilling rigs used in the quarries of Ukraine. One of the effective ways to solve it is to apply the control method of maintaining a constant flow of mechanical power in the bottom hole zone. The implementation of such a control method leads to the necessity of controlling and limiting the resistance torque on the roller cone bit. To solve the problem of determining the resistance torque, we used methods of parameter identification: the Luenberger observation device with adaptation to external influences; estimation of the resistance torque using an extended observation object; the theory of regulators adapting to perturbations. It has been established that the most rational method of identifying the resistance torque on a roller cone bit is an astatic monitoring device, which allows to implement a method of controlling the rotation of the drill rod by a drive mechanism that maintains a constant flow of mechanical energy through the roller cone bit and increases the durability of the roller cone bit.

ANALISIS PERFORMA DIAMOND BIT DAN CONE BIT DENGAN MENGGUNAKAN METODE SPECIFIC ENERGY DI LAPANGAN JS SUMUR P2 DAN Q5 PT. PERTAMINA ASSET 3

The JS field in the North West Java Basin consists of 6 formations, namely Jatibarang, Talang Akar, Baturaja, Upper Cibulakan, Parigi, Cisubuh formations. The formation that is proven to have the potential to develop is the Middle Cibulakan formation. The formations have different hardness characteristics and certainly require different bits to penetrate the specified formation.From these indications, the performance of the drill bits used in the JS field will be analyzed, namely the P2 and Q5 wells. In the P2 well, the performance of the Diamond Bit drill bit at a depth of 0-2500 ft is analyzed. While the Q5 well uses a Roller Cone Bit drill bit at a depth of 0-3000ft. The method used is Specific energy.From the bit performance analysis, the rocks penetrated are from the softest, medium to hard. For Diamond Bit on runs 1-2 show a low value because the penetrated formation is still soft, on runs 3-5 begin to show an increase in SE value because the formation is medium. And on runs 6-8 show a high value because the formation has started to hard. As for the Roller Cone Bit in runs 1-2 shows a low value because the formation is relatively soft, there is an increase in runs 3-5 although there is a decrease in the 4th run due to formation incompactness. However, the 6-8 runs show an increase again because the penetrated formation is classified as hard. So it can be concluded that the rock formation factor can affect the performance of the drill bit.

High-temperature wear mechanism of roller cone bit spiral seal

When drilling, the spiral seal of the roller cone bit and the journal are prone to collision and wear, and the friction heat and downhole high temperature will affect the wear process. The friction and wear experiments of the spiral seal material (20CrNiMo–40Cr) at different temperatures were carried out to study the wear mechanism of the spiral seal and journal of roller cone bit at high temperatures to determine the wear amount, friction coefficient and main wear forms. The wear model of friction pairs is established based on the Archard wear model and experimental results; The wear results at different temperatures are obtained by establishing the spiral seal structure model and simulation research of the roller cone bit. The results show that:(1) Through the friction and wear experiment of friction pair materials, the higher the temperature is the greater the wear amount and friction coefficient are. When the temperature exceeds 100 °C, the wear amount and friction coefficient begin to decline with the increase in temperature. By observing the wear surface morphology, abrasive and adhesive wears occur simultaneously, and the main wear form is adhesive wear under high-temperature conditions.(2) The maximum temperature rise caused by friction and the relationship between wear volume and time at different temperatures are obtained through the simulation of the spiral seal structure. Taking the groove depth value as the index to evaluate the sealing effect, the roller cone bit works in the temperature range (25 °C-400 °C), and high-temperature wear does not affect its sealing performance.

Modelling and Simulating Eulerian Venturi Effect of SBM to Increase the Rate of Penetration with Roller Cone Drilling Bit

Drilling bits are essential downhole hardware that facilitates drilling operations in high-pressure, high-temperature regions and in most carbonate reservoirs in the world. While the drilling process can be optimized, drilling operators and engineers become curious about how drill bits react during rock breaking and penetration. Since it is experimentally expensive to determine, the goal of the study is to maximize the rate of penetration by modeling fluid interactions around the roller cone drilling bit (RCDB), specifying a suitable number of jet nozzles and venturi effects for non-Newtonian fluids (synthetic-based muds), and examining the effects of mud particles and drill cuttings. Ansys Fluent k-epsilon turbulence viscous model, a second order upwind for momentum, turbulent kinetic energy, and dissipation rate, were used to model the specified 1000 kg/m3 non-Newtonian fluid around the roller cone drill bit. The original geometry of the nozzles was adapted from a Chinese manufacturer whose tricone had three jet nozzles. The results of our six redesigned jet nozzles (3 outer, 39.12 mm, and 3 proximal, 20 mm) sought to offer maximum potential for drilling optimization. However, at a pressure of 9.39 × 104 Pa, the wellbore with particle sizes between 0.10 mm and 4.2 mm drill cuttings observed an improved rate of penetration with a rotation speed of 150 r/min.

Pattern and Analysis of Corrugation-Sand Retaining Seals for Tooth Wheel Drill Bits

The existing seal is not designed with a special sand retaining structure, and it is difficult to discharge the mud particles after entering, resulting in serious wear of the seal and premature failure. Therefore, a special-shaped sealing structure for sand blocking of roller cone bits is proposed to solve the problem of sealing wear. Starting from the structural principle, the structural parameters of the special-shaped seal of the sand-retaining flap are designed based on the O-ring, and the sealing principle is analyzed, the formula of grease leakage is derived, and the simulation and optimization analysis are completed with the aid of APDL. This proved the feasibility of the design. The influence law of structural parameters on contact pressure and leakage is obtained, and the formula of leakage is verified; The influence of structural parameters on the contact gap of the sand flap is obtained. Under the condition of optimal combination of structural parameters, the grease leakage is 43 mg/h, a decrease of 85%. Theoretically, it takes 580 h to exhaust the grease, and the contact gap of the sand flap is 0.00019479 mm, a decrease of 95%, which can greatly reduce the wear of the main seal. This study opens up a new idea for seal design.

Comparison of the performance properties of commercially produced roller cone bit coatings

Abstract This paper studies the material aspects of roller cone bits with milled teeth. The research concerns the properties of commercial product overlays provided by the company Glinik Drilling Tools. The analyzed coatings were produced according to the company’s procedures using two surfacing methods: gas welding and plasma transferred arc (PTA) welding. Metallographic observations and chemical composition analyses were carried out. The evaluation criteria in the context of the surfacing application were mechanical properties: hardness, impact strength, and abrasion resistance. The overlays produced by gas welding were characterized by lower hardness, impact strength, and abrasion resistance. The study showed that it differed from the deposit made by the PTA method in the matrix material and in the average size of the tungsten carbides. The dissolution of primary carbides and formation of secondary carbides such as Fe3C and Ni17W3 were found to occur in both surfacing types. This contributes to the increased brittleness of the matrix and reduced wear resistance of the materials.

Thermal Elastohydrodynamic Lubrication Analysis for Rolling Cone Enveloping End Face Worm Drive

To explore the thermal elastohydrodynamic lubrication performance of rolling cone enveloping end face worm drive, the mathematical model of thermal elastohydrodynamic lubrication is established based on the meshing theory of rolling cone enveloping end face worm drive and elastohydrodynamic lubrication theory. With the help of the numerical analysis software MATLAB, the thermal elastohydrodynamic lubrication performance under smooth conditions is selectively analyzed by the multigrid method. Besides, the effects of throat coefficient, cone apex radius and half cone angle of the rolling cone on thermal elastohydrodynamic lubrication performance are analyzed at the meshing out of the transmission pair. The results show that the thermal elastohydrodynamic lubrication film thickness at meshing out of the worm gear is the smallest; the oil film thickness, oil film pressure and oil film temperature are reduced from meshing in to meshing out. The oil film temperature at the interlayer is the largest. The oil film temperature at the end face worm surface is the smallest. The small half-cone angle of the cone apex radius and larger throat coefficient and cone apex radius may achieve better thermal elastohydrodynamic lubrication performance of rolling cone enveloping end face worm drive.

A comparative study of hybrid bit over roller cone and PDC bits

Early hybrid drilling concepts date back to the 1930s, but the development of a viable drilling tool has only become feasible with recent advances in Polycrystalline Diamond Compact (PDC) cutter technology. This paper describes a new generation of hybrid bits based on proven PDC bit designs with roll cutters on the bit periphery. Laboratory and field results will be presented, comparing the performance of hybrid bits with that of conventional PDC and roller bits. A hybrid bit can drill shale and other plastically behaving formations two to four times faster than a roller cone because it is more aggressive and efficient. The penetration rate of a hybrid bit responds linearly to Revolutions Per Minute (RPM), unlike roller taper bits that exhibit an exponential response with an exponent less than one. In other words, a hybrid drill will drill significantly faster than a comparable roller drill in motor applications. Another advantage is the influence of rolling mills on bit dynamics. Compared to conventional PDC bits, torsional oscillations are up to 50% lower, and low-speed slip/slip and high-speed swirl are reduced. This gives the hybrid drill a wider operating window and greatly improves tool face control in directional drilling. The Hybrid Drill is a highly specific drill aimed at traditional cylindrical taper applications limited by the Rate of Penetration (ROP), large-diameter PDC-bit and roller-cone-bit applications limited by torque or Weight on Bit (WOB). Highly interconnected formations with high torque fluctuations can cause premature C3 failure and limit mean operating value torque, and motor and/or P applications where higher ROP and better build speed and tool face control are desired.

Theoretical studies on the nature and conditions of interaction of heel and peripheral nose cones of offset roller cone bits with a bottom hole

An offset of roller cone rotation centerlines is used to increase the mechanical penetration rate while drilling in soft rocks. This enables increasing the area of a cutting structure teeth contact with a bottom hole. The analysis of offset cone drill bit (cutting structure) teeth wear showed that particularly significant wear is characteristic of the transition zone from the heel cone to the nose cone; which leads to significant reduction in the mechanical rate of penetration and a rapid decrease in the hole diameter. The purpose of this paper is to conduct a theoretical research on the nature and conditions of interaction between heel and peripheral nose cones of offset roller cone bits with a bottom hole; which is aimed at improving the efficiency of rock cutting by offset roller cone bits. To achieve the purpose; the authors analyzed data on the nature and causes of wear of existing offset roller cone bit cutting structure (teeth); developed a mathematical model in a cylindrical coordinate system allowing to determine the location and geometric parameters of the gage cone contact area with the hole wall for different roller cone bits sizes; developed a computer solid model for checking the adequacy of the mathematical model by comparing these two models; prepared recommendations for further improvement of the design of existing offset roller cone bit cutting structure (teeth). The research was carried out by the method of mathematical simulation of geometric figures and bodies corresponding to roller cones and a hole. The research has revealed that significant adjustments need to be made to the geometry of the roller cone teeth (currently being patented). This would allow decreasing the areas of cone heel blunting by 15–20 % as well as providing more prolonged contact of base and gage cones with bottom hole and wall surfaces. This allows to reduce wear of teeth in the transition zone of the generatrix from the peripheral nose cone to the gage (heel) cone of the roller cone and to maintain the required specific pressure on the cut rock for a longer period of time and; as a result; to increase both the mechanical penetration rate and the service life of the drilling tools.

Dynamic Characteristics of Metal Seals in Roller Cone Bits

During the drilling process, the sealing performance of the roller cone bits is severely challenged by the complex downhole environment and frequent vibrations. In this paper, a comprehensive thermal–fluid–solid–dynamic multi-field coupling numerical model of new-generation single energizer metal seals (SEMS2) is developed. The instantaneous sealing performance of SEMS2 is studied under periodic vibration, instantaneous shock, and random vibration. Time-domain and frequency-domain changes in the sealing parameters with environmental pressures and rotational speeds under different vibrations are analyzed and compared. The results show that the liquid film distribution and lubrication state on the sealing end faces change constantly as the drill bit vibrates, which in turn affects the sealing performance of the SEMS2. The instantaneous leak rate fluctuates alternately between positive and negative under the three kinds of vibrations, aggravating the tendency of lubricant oil leakage and drilling mud invasion. With increasing environmental pressure and rotational speed, the fluctuation amplitudes of the maximum temperature increase, leakage rate, and friction torque under random vibration and instantaneous shock are significantly larger than those under periodic vibration. Our model and results have important theoretical significance for improving the design system of metal seals for drill bits.

About the experience of using hardmetals in the production of roller cone bits at Volgaburmash JSC

Since 2017, Volgaburmash JSC (Samara, Russia) tested purchased 90%WC–10%Co carbide powder mixtures and finished carbide drill bits from various manufacturers. The work was carried out in order to check the possibility of using purchased products as raw materials at the plant to reduce the production cycle for the manufacture of carbide inserts for roller cone bits. This intercommodity substitution (outsourcing) is carried out with the aim of potential cone bit cost reduction and production process acceleration so that the plant can operate in the heavily competitive environment of foreign and domestic markets. The article focuses on the analysis and detailed comparison of the micro- and macrostructure, physical, mechanical, chemical and processing properties of purchased hard-alloy mixtures and sintered inserts of various manufacturers including Volgaburmash JSC. All properties of materials under study were determined in accordance with the VBM JSC company standard STP 582-17. Much attention is paid to comparing crack resistance or Palmqvist fracture toughness values of the alloy and analysis of microstructure images and fracture propagation pattern after using scanning electron microscopy tests. In addition, consideration is given to such important hard alloy properties as hardness and transverse bending strength. Based on the results of the conducted research, conclusions are presented on the expediency of using purchased hard-alloy materials at the Volgaburmash JSC metallurgical shop in comparison with internally manufactured materials.

Bit optimization method for rotary impact drilling based on specific energy model

In the field application of oil and gas well drilling, it is found that the previous mechanical specific energy (MSE) model cannot well monitor the data of rotary impact drilling, and there are great errors. The main reason is that these MSE models focus on the correction of hydraulic and rate of penetration (ROP), ignoring the impact energy generated by hydraulic impactor, thereby reducing drilling efficiency (DE). Therefore, this paper improves weight-on-bit (WOB) and hydraulic parameter displacement Q to establish the rotary hydraulic impact specific energy model (RHISE) of polycrystalline diamond compact (PDC) and roller cone bits, and establishes the corresponding bit optimization model (BO) considering drilling cost (CT), RHISE, wear evaluation index (WI) and ROP. Applying this model to four wells in Shunbei, results show that the ROP of roller cone bits increases by about 10% and the DE increases by about 8% compared with the PDC bit. Compared with the combination of staggered PDC and roller cone bits (RCB) with hydraulic impactor, DE increased by 16% and BO increased by 4%. Therefore, the comprehensive efficiency of RCB combined with hydraulic impactor is better than that of PDC bit combined with hydraulic impactor.