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.

Design front rake angle of PDC bit based on SolidWorks simulation method

2016 ◽  
Vol 1 (3) ◽  
pp. 627 ◽  
Author(s):  
Xiaoming HAN ◽  
Chenxu LUO ◽  
Xingyu HAN
Keyword(s):  
Hard Rock ◽  
Simulation Analysis ◽  
Soft Rock ◽  
Polycrystalline Diamond ◽  
Simulation Method ◽  
Rake Angle ◽  
Element Simulation ◽  
Pdc Bit ◽  
Coal Rock ◽  
Polycrystalline Diamond Compact

<span lang="EN-US">In order to solve the bit front rake angle parameter selection problem of under different coal rock, it is proposed in polycrystalline diamond compact no core bit as the research object, and established a bit compact two-dimensional stress model of cutting teeth. The result shows that the front rake angle is the factor of cutting force and the drilling efficiency. Application of SolidWorks simulation carries out the finite element simulation analysis respectively to different front rake angle of bit model under the condition of soft rock and hard rock. Form the simulation it concludes that under the condition of soft rock and hard rock, the optimal front rake angle is 10° and 15° respectively. It is obtained that the strength of the bit is largest and the life is longest on the best front rake angle of bit.</span>

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.

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.

Assured Stability of Drillstrings Equipped With Polycrystalline Diamond Compact (PDC) Bits

2003 ◽  
Author(s):  
M. A. Elsayed
Keyword(s):  
Stability Analysis ◽  
Geothermal Energy ◽  
Hard Rock ◽  
Rock Type ◽  
Polycrystalline Diamond ◽  
Deep Wells ◽  
Drilling Parameters ◽  
Pipe Joints ◽  
Polycrystalline Diamond Compact ◽  
Oil Gas

Drillstrings equipped with PDC bits are commonly used to drill for oil, gas and geothermal energy. Drillstring instability — defined as the tendency of self-excited vibrations (chatter) to grow with time — causes failure of PDC bits as well as pipe joints. This problem becomes particularly severe in deep wells and hard rock. Much work has been performed in predicting stability. Bit and drillstring geometry as well as rock type affect stability. In this paper, we propose a scheme to assure stability for a given drillstring regardless of bit geometry, utilizing the desired drilling parameters. The effect of bit geometry and rock type in the classic stability analysis are replaced by the drilling parameters, namely: weight-ob-bit (WOB), rate of penetration (ROP) and speed (RPM). Experimental data obtained at Sandia National Labs, Albuquerque, N.M. is used to verify the assured stability equation. This approach is much simpler that classic stability analysis.

Analysis of Coupling Between Axial and Torsional Vibration in a Compliant Model of a Drillstring Equipped With a PDC Bit

2002 ◽  
Author(s):  
M. A. Elsayed ◽  
David W. Raymond
Keyword(s):  
Hard Rock ◽  
Polycrystalline Diamond ◽  
Operating Conditions ◽  
Axial Vibration ◽  
Rock Drilling ◽  
Stick Slip ◽  
Vibration Data ◽  
Pdc Bit ◽  
Show Evidence ◽  
Polycrystalline Diamond Compact

In this paper, we discuss results of rock drilling tests at Sandia National Laboratories’ Hard Rock Drilling Facility (HRDF). The HRDF incorporates a drillstring with axial and torsional compliance and is equipped with a coring bit having PDC (Polycrystalline Diamond Compact) cutters. We measure and analyze chatter and show evidence of stick-slip as well as coupling between axial and torsional vibrations. We show the coupling signature in axial vibration data in the form of side bands indicating frequency modulation at the torsional natural frequency. The influence of operating conditions on the bit response is shown.

Development of New PDC Bits for Drilling of Geothermal Wells—Part 2: Field Testing

1992 ◽  
Vol 114 (4) ◽  
pp. 332-338
Author(s):  
S. Misawa ◽  
H. Karasawa
Keyword(s):  
Hard Rock ◽  
Field Tests ◽  
Polycrystalline Diamond ◽  
Field Testing ◽  
Hot Dry Rock ◽  
Rock Formations ◽  
Geothermal Wells ◽  
Project Site ◽  
Polycrystalline Diamond Compact

In order to develop polycrystalline diamond compact (PDC) bits of about 8-1/2 in. in diameter which are able to drill geothermal wells, we have conducted the investigation with respect to the structure of a PDC cutter and rake angles, etc., by means of fundamental laboratory and field tests. New PDC core bits of 8-15/32 in. diameter were designed and manufactured based on the results of these tests. Then, field tests using them were carried out in geothermal wells at Hijiori in Yamagata prefecture, Hot Dry Rock project site in Japan, on September 1989 and October 1990. It became clear that the new PDC core bit can be sufficiently applied to the drilling of heterogeneous hot-hard rock formations from the tests.

Modeling of Cutting Rock: From PDC Cutter to PDC Bit—Modeling of PDC Cutter

SPE Journal ◽  
2021 ◽  
pp. 1-21
Author(s):  
Pengju Chen ◽  
Stefan Miska ◽  
Mengjiao Yu ◽  
Evren Ozbayoglu
Keyword(s):  
Stress State ◽  
Cutting Forces ◽  
Polycrystalline Diamond ◽  
Rake Angle ◽  
Cutting Process ◽  
Model Studies ◽  
3D Space ◽  
Pdc Bit ◽  
Polycrystalline Diamond Compact ◽  
Good Agreement

Summary The main purpose of this paper is to present our polycrystalline diamond compact (PDC) cutter model and its verification. The PDC cutter model we developed is focused on a PDC cutter cutting a rock in 3D space. The model studies the forces between a cutter and a rock and applies the theory of poroelasticity to calculate the stress state of the rock during the cutting process. Once the stress state of the rock is obtained, the model can then predict rock failure by the modified Lade criterion (Ewy 1999). This work also developed a trial-and-error procedure to predict cutting forces, and the stress state of a rock before cutting process is also considered. A complete verification of the cutter model is conducted. The model results (i.e., predicted cutting forces) are compared with measured cutting forces from cutter tests in multiple published articles. The major influencing factors on cutting forces—backrake angle, side-rake angle, depths of cut, worn depth (or wear flat area), and hydrostatic pressure—are all studied and verified. A good agreement between the model results and cutter test data is found, and the overall mean relative error is approximately 15%. The influence of inhomogeneous precut stress state of a rock is also studied. Overall, the cutter model in this paper is complete and accurate. It is ready to be integrated into a PDC bit model.

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.

Sign in / Sign up

Export Citation Format

Share Document