scholarly journals Experimental study on rock-breaking mechanism of micro-coring PDC bit

2021 ◽  
Author(s):  
Shengsong Huang ◽  
Qingchun Gao ◽  
Xian Ye ◽  
Yingxin Yang ◽  
Kuilin Huang
Keyword(s):  
Experimental Study ◽  
Static Pressure ◽  
Rock Breaking ◽  
Rate Of Penetration ◽  
Rock Samples ◽  
Pdc Bit ◽  
Breaking Mechanism ◽  
Core Column

AbstractIn this paper, in order to study the rock-breaking mechanism of the micro-coring PDC bit, a series of unit breaking experiments containing 2 breaking forms (static-pressure breaking and fracture breaking) are conducted on core columns of sandstone, limestone, and granite. Besides, a full-sized micro-coring PDC bit with a diameter of 152.4 mm is designed and manufactured and is used to conduct an indoor experiment on multiple sized sandstone core columns. The unit breaking experiment results show that ROP (rate of penetration) of the fracture breaking is higher than the static-pressure breaking. The indoor experiment results of the full-sized bit show that ROP of the micro-coring PDC bit is 49–112% higher than the conventional bit and that the diameter of core column shows greater influence on ROP, while the height of the column shows smaller. Moreover, the micro-coring PDC bit realizes volumetric fracture on all of the three types of rock samples. Since volumetric fracture produces large rock debris, the rock-breaking efficiency and ROP of the micro-coring PDC bit will be improved significantly.

scholarly journals Unit Experimental Study on Impact Crushing Rock of the Microcoring PDC Bit

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Yingxin Yang ◽  
Dongdong Song ◽  
Kuilin Huang ◽  
Haitao Ren ◽  
Jian Zhou
Keyword(s):  
Experimental Study ◽  
Static Pressure ◽  
Penetration Rate ◽  
Central Area ◽  
Rock Breaking ◽  
Drill Bit ◽  
Pdc Bit ◽  
Core Column ◽  
Impact Crushing ◽  
Breaking Work

In light of the situation of sliced or powdery cuttings produced by conventional PDC bit, it is found that they are not convenient for geological logging and stratification. The unit crushing experiment which contains two breaking forms (static-pressure breaking and impact) is conducted on core columns of sandstone, limestone, and granite. This experimental study showed the following: The breaking work ratio of the three core column types is much less than that of the flat rock. The height of the core column has little effect on the bit penetration rate, while core column diameter has greater effect on the bit penetration rate. The experimental results further indicate that a core column has been generated in the central area of the drill bit, which is beneficial to the volume breaking of the rock and can improve the rock-breaking efficiency of the drill bit. The microcoring bit is suitable for raising speed in soft, medium, and hard formations and is helpful for geological logging.

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.

Experimental Study on Longmaxi Shale Breaking Mechanism with Micro-PDC Bit

2017 ◽  
Vol 50 (10) ◽  
pp. 2795-2804 ◽  
Author(s):  
Teng Wang ◽  
Xiaohua Xiao ◽  
Haiyan Zhu ◽  
Jingying Zhao ◽  
Yuheng Li ◽  
...  
Keyword(s):  
Experimental Study ◽  
Longmaxi Shale ◽  
Pdc Bit ◽  
Breaking Mechanism

scholarly journals Study on rock breaking mechanism of PDC bit with rotating module

2020 ◽  
Vol 192 ◽  
pp. 107312
Author(s):  
Kuilin Huang ◽  
Yingxin Yang ◽  
Yang Liu ◽  
Yunpeng Zhong ◽  
Haitao Ren
Keyword(s):  
Rock Breaking ◽  
Pdc Bit ◽  
Breaking Mechanism

scholarly journals Working Load Characteristics of the PDC-Cone Composite Bit under Impact and Scraping

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Kuilin Huang ◽  
Chunxiao Zhou ◽  
Yingxin Yang ◽  
Haitao Ren ◽  
Qingzhi Niu
Keyword(s):  
Digital Simulation ◽  
Bending Moment ◽  
Lateral Force ◽  
Rock Breaking ◽  
Structure Design ◽  
Directional Drilling ◽  
Pdc Bit ◽  
Breaking Mechanism ◽  
Load Characteristics ◽  
Analysis System

The PDC-roller hybrid bit combines the cutting structure of a tricone bit with a PDC bit. It can achieve good results, breaking rock in directional drilling, drilling in inhomogeneous formations, and drilling in formations with high levels of hardness, and it can achieve the engineering goals of increasing speed and efficiency. First, we analyzed the rock-breaking mechanism of the composite bit and the principles of cushioning, torsion reduction, and prebreaking of the cone teeth during the breaking of rock. Second, cutting load models of the cone teeth and PDC teeth were established through unit experiments and through the calculation methods of the axial force, lateral force and torque, and lateral bending moment of the composite bit. Third, the digital simulation and analysis system was improved to include the function of calculating the working load of the composite bit. Taking an 8-1/2 inch, 2 + 4 type composite bit as an example, the working load characteristics of three cutting structures (cone, blade, and composite) were analyzed and compared. The analysis shows that the composite bit has high drilling efficiency, obvious deviation advantages, and good working stability under specific formation conditions. This paper provides technical support for the performance analysis, formation adaptability evaluation, and cutting structure design optimization of the PDC-cone bit.

Experimental study on the rock-breaking mechanism of disc-like hybrid bit

2018 ◽  
Vol 161 ◽  
pp. 541-550 ◽  
Author(s):  
Shiwei Niu ◽  
Hualin Zheng ◽  
Yingxin Yang ◽  
Lian Chen
Keyword(s):  
Experimental Study ◽  
Rock Breaking ◽  
Breaking Mechanism

Research on rock-breaking mechanism of cross-cutting PDC bit

2018 ◽  
Vol 161 ◽  
pp. 657-666 ◽  
Author(s):  
Yingxin Yang ◽  
Chunliang Zhang ◽  
Min Lin ◽  
Lian Chen
Keyword(s):  
Rock Breaking ◽  
Pdc Bit ◽  
Breaking Mechanism

Study on Rock-Breaking Simulation and Experiment of Double Disc Cutter of TBM

2016 ◽  
Vol 23 ◽  
pp. 80-88
Author(s):  
F. Lu ◽  
C. Zhang ◽  
J. Sun ◽  
J.X. Tian ◽  
M. Liu ◽  
...  
Keyword(s):  
Rock Breaking ◽  
Disc Cutter ◽  
Element Analysis ◽  
Breaking Effect ◽  
The Finite Element Analysis ◽  
Breaking Mechanism ◽  
Simulation And Experiment ◽  
Tbm Cutter ◽  
Cutter Spacing ◽  
The Impact

In order to improve working efficiency of the tunneling process and extend working life of disc cutter, explore the impact of cutter spacing and loading for the cutter rock-breaking effect. With the theory of rock crushing, Based on the finite element analysis software ABAQUS, the process of disc cutter breaking rock is simulated, considering the adjacent cutters sequential constraints, then, to make sure two cutter space with the method of SE in experiment.The simulation results showed that the optimal cutter spacings were both about 80mm in the same loading and the sequentially loading, but the rock-breaking effect of sequentially loading is better than the same loading. The experimental data showed that the minimum specific energy of rock breaking is appeared cutter spacing between 80mm and 90mm. Thus, the correctness and rationality of the simulation was verified. The study is good for understanding the rock-breaking mechanism of double disc cutter and has a certain promoting value to optimize TBM cutter system.Keywords:TBM, rock fragmentation, ABAQUS, cutter spacing, sequentially cutting

An Experimental Study of Local Wall Shear Stress, Surface Static Pressure, and Flow Visualization Upstream, Alongside, and Downstream of a Blade Endwall Corner

1991 ◽  
Vol 113 (4) ◽  
pp. 626-632 ◽  
Author(s):  
A. K. Abdulla ◽  
R. K. Bhargava ◽  
R. Raj
Keyword(s):  
Experimental Study ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Flow Visualization ◽  
Static Pressure ◽  
Leading Edge ◽  
Chord Length ◽  
Corner Region ◽  
Wall Shear ◽  
Blade Leading Edge

The experimental study reported in this paper was performed to acquire information on the distribution of wall shear stress and surface static pressure in a blade endwall corner. The blade endwall corner region investigated was divided into three sections: 0.4 chord length upstream of the blade leading edge, inside the endwall corner region, and one chord length downstream of the blade trailing edge. The maximum increases in the values of wall shear stress were found to exist on the endwall, in the corner region, between the blade leading edge and the location of maximum blade thickness (≈ 140 percent maximum increase, compared to its far upstream value, at x/D = 6). Surface flow visualization defined the boundaries of the vortex system and provided information on the direction and magnitude of the wall shear stress. The acquired results indicated that the observed variations of wall shear stress and surface static pressure were significantly influenced by the interaction of secondary flows with pressure gradients induced by the presence of blade curvature.

EXPERIMENTAL STUDY ON THE EFFECT OF DRILL QUALITY ON BONE TEMPERATURE IN DRILLING

2018 ◽  
Vol 30 (02) ◽  
pp. 1850018 ◽  
Author(s):  
Khurshid Alam ◽  
Syed Husain Imran ◽  
Abdullah Al-Shabibi ◽  
Mojtaba Ghodsi ◽  
Vadim Silberschmidth
Keyword(s):  
Experimental Study ◽  
Bone Tissue ◽  
Femoral Shaft ◽  
Tissue Temperature ◽  
Bone Drilling ◽  
Thermal Necrosis ◽  
Bone Material ◽  
Rate Of Penetration ◽  
Lower Temperature ◽  
Drilling Conditions

Bone drilling is widely performed in orthopedics for fixation and reconstruction of bone. In bone drilling, a hard metallic drill penetrates into the bone tissue which may cause trauma. Shear deformation of the bone material and friction between the drill and bone may induce elevated temperature in bone tissue. Temperature above a certain level may seriously harm the tissue, leading to several postoperative complications. The purpose of the current study is to measure and compare temperature in bone drilling using sharp and worn drill. Drilling tests were performed on cortical bone obtained from femoral shaft of a cow. A parametric study was conducted to quantify bone temperature using a range of drilling speeds and feed rates using drills having sharp and worn cutting edges with and without cooling environment. The temperature was measured using thermocouples, and wear of the cutting edges of the drill was measured using a scanning profilometer. Experimental results demonstrated lower temperature in bone using a sharp drill compared with a worn drill for similar drilling conditions. The bone temperature was found to rise with drill rotational speed, rate of penetration and size of the drill with and without cooling. Blunt drills were found more crucial for inducing thermal necrosis in bone.

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