Issues in Polycrystalline Diamond Compact Cutter–Rock Interaction From a Metal Machining Point of View—Part II: Bit Performance and Rock Cutting Mechanics

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Demeng Che ◽  
Peidong Han ◽  
Ping Guo ◽  
Kornel Ehmann
Keyword(s):  
Metal Cutting ◽  
Polycrystalline Diamond ◽  
Rock Cutting ◽  
Point Of View ◽  
Rock Interaction ◽  
Metal Machining ◽  
Pdc Bit ◽  
Rock Cutting Mechanics ◽  
Cutting Processes ◽  
Polycrystalline Diamond Compact

In Part I of this paper, the issues related to temperature, stress and force were reviewed and parallels were drawn between both metal machining and rock cutting. Part II discusses the issues more directly related to polycrystalline diamond compact (PDC) bit performance and rock mechanics. However, relevant issues in various metal cutting processes will continue to be presented to clarify the gaps and similarities between these two classes of processes.

Issues in Polycrystalline Diamond Compact Cutter–Rock Interaction From a Metal Machining Point of View—Part I: Temperature, Stresses, and Forces

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Demeng Che ◽  
Peidong Han ◽  
Ping Guo ◽  
Kornel Ehmann
Keyword(s):  
Metal Cutting ◽  
Polycrystalline Diamond ◽  
Point Of View ◽  
Rock Properties ◽  
Machining Processes ◽  
Temperature Stresses ◽  
Rock Interaction ◽  
Metal Machining ◽  
Rock Interface ◽  
Polycrystalline Diamond Compact

This paper provides a comprehensive review of the literature that deals with issues surrounding the polycrystalline diamond compact (PDC) cutter–rock interface during rock cutting/drilling processes. The paper is separated into two parts addressing eight significant issues: Part I deals with fundamental issues associated with temperature/stress distribution and loading force prediction, while Part II focuses on issues related to PDC cutter/bit performance, wear and other failure phenomena, rock removal mechanism and cutting theory, rock properties, and numerical modeling of cutter–rock interaction. Experimental, analytical, and numerical methods are included into the investigation of the above-mentioned eight issues. Relevant concepts from metal cutting, micromachining, and other machining processes are also introduced to provide important insights and draw parallels between these interrelated fields.

Fragmentation Characteristics of Rocks Under Indentation by a Single Polycrystalline Diamond Compact Cutter

2021 ◽  
Vol 143 (10) ◽  
Author(s):  
Zhaosheng Ji ◽  
Huaizhong Shi ◽  
Xianwei Dai ◽  
Hengyu Song ◽  
Gensheng Li ◽  
...  
Keyword(s):  
Contact Force ◽  
Brittle Failure ◽  
Failure Modes ◽  
Polycrystalline Diamond ◽  
Rake Angle ◽  
Von Mises Stress ◽  
Rock Interaction ◽  
Initiation Point ◽  
Pdc Bit ◽  
Polycrystalline Diamond Compact

Abstract Polycrystalline diamond compact (PDC) bit accounts for the most drilling footage in the development of deep and geothermal resources. The goal of this paper is to investigate the PDC cutter-rock interaction and reveal the rock fragmentation mechanism. A series of loading and unloading tests are conducted to obtain the curves of contact force versus penetration displacement. A single practical PDC cutter is fixed on the designed clamping devices that are mounted on the servo experiment system TAW-1000 in the tests. The craters morphology and quantified data were obtained by scanning the fragmented rock specimen using a three-dimensional morphology scanner. Finally, a numerical model is established to get the stress and deformation fields of the rock under a single PDC cutter. The results show that there are two kinds of failure modes, i.e., brittle failure and plastic failure, in the loading process. Marble is more prone to brittle fracture and has the lowest specific energy, followed by shale and granite. The brittle failure in marble mainly occurs behind the cutter while that happens ahead of the cutter for shale. Curves of contact force versus penetration displacement illustrate that a cutter with a back rake angle of 40 deg has a better penetration result than that with a back rake angle of 30 deg. Enhancing loading speed has a positive effect on brittle fragmentation. The distribution of von Mises stress indicates the initiation point and direction, which has a good agreement with the experiment. The research is of great significance for optimizing the PDC bit design and increasing the rate of penetration.

Development of New PDC Bits for Drilling of Geothermal Wells—Part 1: Laboratory Testing

1992 ◽  
Vol 114 (4) ◽  
pp. 323-331 ◽  
Author(s):  
H. Karasawa ◽  
S. Misawa
Keyword(s):  
Hard Rock ◽  
Rock Type ◽  
Penetration Rate ◽  
Polycrystalline Diamond ◽  
Rock Cutting ◽  
Rake Angle ◽  
Well Drilling ◽  
Pdc Bit ◽  
Geothermal Wells ◽  
Polycrystalline Diamond Compact

Rock cutting, drilling and durability tests were conducted in order to obtain data to design polycrystalline diamond compact (PDC) bits for geothermal well drilling. Both conventional and new PDC bits with different rake angles were tested. The rock cutting tests revealed that cutting forces were minimized at −10 deg rake angle independent of rock type. In drilling and durability tests, a bit with backrake and siderake angles of −10 or −15 deg showed better performance concerning the penetration rate and the cutter strength. The new PDC bit exhibited better performance as compared to the conventional one, especially in hard rock drilling. Furthermore, a new PDC core bit (98.4 mm o. d., 66 mm i. d.) with eight cutters could be successfully applied to granite drilling equally as well as a bit with twelve cutters.

Mathematical Modeling of PDC Bit Drilling Process Based on a Single-Cutter Mechanics

1993 ◽  
Vol 115 (4) ◽  
pp. 247-256 ◽  
Author(s):  
A. K. Wojtanowicz ◽  
E. Kuru
Keyword(s):  
Polycrystalline Diamond ◽  
Rock Properties ◽  
Drilling Process ◽  
Drilling Parameters ◽  
Pdc Bit ◽  
Analytical Development ◽  
Assumed Similarity ◽  
Balance Of Forces ◽  
Bit Life ◽  
Polycrystalline Diamond Compact

An analytical development of a new mechanistic drilling model for polycrystalline diamond compact (PDC) bits is presented. The derivation accounts for static balance of forces acting on a single PDC cutter and is based on assumed similarity between bit and cutter. The model is fully explicit with physical meanings given to all constants and functions. Three equations constitute the mathematical model: torque, drilling rate, and bit life. The equations comprise cutter’s geometry, rock properties drilling parameters, and four empirical constants. The constants are used to match the model to a PDC drilling process. Also presented are qualitative and predictive verifications of the model. Qualitative verification shows that the model’s response to drilling process variables is similar to the behavior of full-size PDC bits. However, accuracy of the model’s predictions of PDC bit performance is limited primarily by imprecision of bit-dull evaluation. The verification study is based upon the reported laboratory drilling and field drilling tests as well as field data collected by the authors.

Analytical Modeling of Heat Transfer in Polycrystalline Diamond Compact Cutters in Rock Turning Processes

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Demeng Che ◽  
Kornel Ehmann ◽  
Jian Cao
Keyword(s):  
Heat Transfer ◽  
Analytical Solution ◽  
Transfer Problem ◽  
Mixed Boundary ◽  
Separation Of Variables ◽  
Polycrystalline Diamond ◽  
Experimental Tests ◽  
Rock Cutting ◽  
Polycrystalline Diamond Compact ◽  
Temperature Responses

Heat transfer phenomena at the rock–cutter interface are extremely significant since they affect the polycrystalline diamond compact (PDC) cutter's performance in rock cutting/drilling processes. The understanding of how temperature and heat flux responses in the cutter influence the intrinsic mechanisms of the rock–cutter interactions is an essential prerequisite for providing insights to enhance the performance of PDC cutters and to optimize rock cutting/drilling processes. In this paper, a mixed boundary value heat transfer problem was formulated to analytically describe the heat transfer phenomena in the PDC cutters during two-dimensional (2D) orthogonal rock cutting under steady state conditions. An analytical solution in the form of an infinite series was derived based on the method of separation of variables, the use of appropriate simplifications in the formulated problem and the separation of the thermal from the mechanical phenomena. A series of experimental tests were conducted on a newly developed rock cutting testbed to calibrate the process parameters in the analytical solution and then to confirm the validity of the assumed boundary conditions. The comparison between the newly derived analytical solution and the experimental data shows a good match in terms of temperature responses during rock cutting performed by PDC cutters.

Rock Cutter Interactions in Linear Rock Cutting

2016 ◽  
Author(s):  
Demeng Che ◽  
Weizhao Zhang ◽  
Kornel F. Ehmann
Keyword(s):  
Experimental Data ◽  
Oil And Gas ◽  
Cutting Tool ◽  
Polycrystalline Diamond ◽  
Rock Cutting ◽  
Testing Methods ◽  
Gas Drilling ◽  
Complex Interactions ◽  
On Chip ◽  
Polycrystalline Diamond Compact

Polycrystalline diamond compact (PDC) cutter, as a major cutting tool, has been widely applied in oil and gas drilling processes. The understanding of the complex interactions at the rock and cutter interfaces are essential for the advancement of future drilling technologies, yet, these interactions are still not fully understood. Linear cutting of rock, among all the testing methods, avoids the geometric and process complexities and offer the most straightforward way to reveal the intrinsic mechanisms of rock cutting. Therefore, this paper presents an experimental study of the cutter’s cutting performance and the rock’s failure behaviors on a newly developed linear rock cutting facility. A series of rock cutting tests were designed and performed. The acquired experimental data was analyzed to investigate the influences of process parameter and the rock’s mechanical properties on chip formation and force responses.

Chip Formation and Force Responses in Linear Rock Cutting: An Experimental Study

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Demeng Che ◽  
Weizhao Zhang ◽  
Kornel Ehmann
Keyword(s):  
Experimental Study ◽  
Chip Formation ◽  
Oil And Gas ◽  
Cutting Tool ◽  
Polycrystalline Diamond ◽  
Rock Cutting ◽  
Gas Drilling ◽  
Complex Interactions ◽  
On Chip ◽  
Polycrystalline Diamond Compact

Polycrystalline diamond compact (PDC) cutters, as a major cutting tool, have been widely applied in oil and gas drilling processes. The understanding of the complex interactions at the rock and cutter interfaces is essential for the advancement of future drilling technologies; yet, these interactions are still not fully understood. Linear cutting of rock, among all the testing methods, avoids the geometric and process complexities and offers the most straightforward way to reveal the intrinsic mechanisms of rock cutting. Therefore, this paper presents an experimental study of the cutter’s cutting performance and the rock’s failure behaviors on a newly developed linear rock cutting facility. A series of rock cutting tests were designed and performed. The acquired experimental data was analyzed to investigate the influences of process parameters and the rock’s mechanical properties on chip formation and force responses.

scholarly journals Simulation and Experimental Study of the Rock Breaking Mechanism of Personalized Polycrystalline Diamond Compact Bits

2020 ◽  
Vol 13 (5) ◽  
pp. 122-131
Author(s):  
Yu Jinping ◽  
◽  
Zou Deyong ◽  
Sun Yuanxiu ◽  
Zhang Yin
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Tensile Stress ◽  
Crack Propagation ◽  
Tangential Force ◽  
Polycrystalline Diamond ◽  
Rock Breaking ◽  
Pdc Bit ◽  
Breaking Mechanism ◽  
Polycrystalline Diamond Compact

Rock breaking is a complex physical process that can be influenced by various factors, such as geometrical shape and cutting angle of rock breaking tools. Experimental study of the rock breaking mechanism of personalized bits is restricted due to long cycle and high cost. This study simulated the rock breaking mechanism of polycrystalline diamond compact (PDC) bit by combining finite element method and experiment. The simulation was performed to shorten the period and reduce the cost of studying the rock breaking mechanism of PDC bits. A rock breaking finite element model for sting cutters of personalized PDC bit was established to simulate the rock breaking process. The crack propagation pattern, dynamic stress of rock breaking, and rock breaking mechanism of sting cutters of personalized PDC bit were analyzed. The correctness of the simulation results was verified through experiments. Results demonstrate that the rock breaking load increases with the crack propagation in the fracture initiation and propagation stages, with the maximum tangential force of 1062.5 N and maximum axial force of 1850.0 N. The load changes in a small range when the crack penetrates the rock, with the tangential force of 125.0–500.0 N and axial force of 375.0–875.0 N. The rock breaking mechanism of the sting cutters of bit is consistent with maximum tensile stress theory. The rock begins to break when the tensile stress of rock is 36.9 MPa. The sting cutters of personalized PDC bit have better wear resistance than the sting cutters of conventional bit. The average wear rates of personalized PDC and conventional bits are 1.74E-4 and 2.1E-4 mm/m, respectively. This study serves as reference for shortening the study period of rock breaking mechanism, efficiently designing personalized PDC bit structure, reducing bit wear, and enhancing rock breaking efficiency.

scholarly journals Investigation of the Cross-Cutting Polycrystalline Diamond Compact Bit Drilling Efficiency

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Chun-Liang Zhang ◽  
Ying-Xin Yang ◽  
Hai-Tao Ren ◽  
Can Cai ◽  
Yong Liu ◽  
...  
Keyword(s):  
Cutting Force ◽  
Polycrystalline Diamond ◽  
Rock Breaking ◽  
The Novel ◽  
Cutting Efficiency ◽  
Bottom Hole ◽  
Pdc Bit ◽  
The Cross ◽  
Polycrystalline Diamond Compact ◽  
Cutting Modes

The parallel track scraping principle of conventional PDC bits largely limits the cutting efficiency and working life in deep formations. Cross-cutting polycrystalline diamond compact (PDC) bit may be an efficient drilling tool that increases the rock-breaking efficiency through both cross-cutting and alternate-cutting modes of the PDC cutter. The motion track equation of the cross-cutting PDC bit was derived by using the compound coordinate system, and the motion track was analyzed. Meanwhile, through the unit experiment and discrete element simulation, the cutting force, volume-specific load, and crack propagation were analyzed under different cutting modes. Through establishing a nonlinear dynamic model of the bit-rock system, the speed-up mechanism of the novel bit was analyzed based on rock damage, rock stress state, and motion characteristic of the bit during the rock-breaking process. Compared with unidirectional cutting, cross-cutting produces less cutting force, more brittle fracture, and a greater decrease of formation strength. The novel PDC bit can put more rock elements into a tensile stress condition than a conventional PDC bit, and the plastic energy dissipation ratio of the cross-cutting PDC bit is lower while the damage energy consumption ratio is higher than they are for conventional bits, which is beneficial to increasing the ratio of fracture failure and improving rock-breaking efficiency. Laboratory drilling tests show that the cross-cutting PDC bit can create mesh-like bottom-hole features. Drilling contrast experiments show that a mesh-like bottom-hole pattern can be obtained by using the cross-cutting PDC bit, of which the ROP is obviously higher than that of the conventional bit when drilling in sandstone or limestone formation. Meanwhile, the influence of deviation angle, weight on bit, and rock properties on cutting efficiency of the cross-cutting PDC bit are studied.

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