scholarly journals Failure mechanisms of polycrystalline diamond compact drill bits in geothermal environments

1981 ◽  
Author(s):  
E.R. Hoover ◽  
L.E. Pope
1985 ◽  
Vol 107 (4) ◽  
pp. 534-542 ◽  
Author(s):  
C. L. Hough ◽  
B. Das

The wear characteristics of polycrystalline diamond compact (PDC) drill bits were investigated in the context of drilling small holes in a hard abrasive medium. An efficient method for measuring wear of the PDC drill bits was developed. The wear test results were grouped or categorized in terms of rotary speed, feed and wear or failure characteristics. Contrary to the three classical wear phases (break-in, uniform wear and rapid breakdown) of the single material cutters, four distinctive wear phases were formed for the PDC cutters: I–break-in, II–diamond wear, III–carbide wear, and IV–rapid breakdown. The characteristics of the wear phases were identified and some suggestions were made to alleviate the wear problem.


1986 ◽  
Vol 108 (4) ◽  
pp. 310-314
Author(s):  
C. L. Hough ◽  
B. Das ◽  
T. G. Rozgonyi

Mathematical models for bit life of polycrystalline diamond compact (PDC) drill bits were developed for drilling small holes in hard abrasive media. Based on the wear-out criterion of an average 0.060 in. (1.5 mm) flank wear land, bit life equations were formulated in three forms: bit life versus rotary speed and feed rate, bit life versus rotary speed and penetration rate, and wear rate versus cutting speed and cutter engagement area. The traditional linear-logarithmic model proved inadequate to describe bit life, whereas the quadratic-logarithmic model provided the best bit life prediction equation. Consequently, it would be possible to predict the optimum economical drilling conditions more accurately by employing a quadratic-logarithmic based bit life equation. The equation demonstrated the ability to predict the bit life precisely under different modes of wear.


Wear ◽  
1992 ◽  
Vol 156 (1) ◽  
pp. 133-150 ◽  
Author(s):  
Lin Tze-Pin ◽  
Michael Hood ◽  
George A. Cooper ◽  
Li Xiaohong

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042093097
Author(s):  
Dou Xie ◽  
Zhiqiang Huang ◽  
Yuqi Yan ◽  
Yachao Ma ◽  
Yuan Yuan

Polycrystalline diamond compact bits have been widely used in the Oil and Gas drilling industry, despite the fact that they may introduce undesired vibration into the drilling process, for example, stick-slip and bit bounce, which accelerate the failure rate and lead to higher drilling costs. First, we develop an innovative ridge-ladder-shaped polycrystalline diamond compact cutter, which has ridge-shaped cutting faces and multiple cutting edges with stepped distribution, in the hope of reducing vibration and improving drilling speed. Then, the scrape tests of ridge-ladder-shaped and general polycrystalline diamond compact cutters are carried out in a laboratory, indicating that the cutting, lateral, and longitudinal forces on ridge-ladder-shaped polycrystalline diamond compact cutters are smaller and with minor fluctuations. Due to different rock-breaking mechanisms, ridge-ladder-shaped polycrystalline diamond compact cutters have higher cutting efficiency compared to general polycrystalline diamond compact cutters, which is also verified experimentally. Finally, the drilling characteristics of a new polycrystalline diamond compact bit fitted with some ridge-ladder-shaped polycrystalline diamond compact cutters are compared to those of a general polycrystalline diamond compact bit by means of finite element simulation. The results show that introducing ridge-ladder-shaped polycrystalline diamond compact cutters can not only reduce the stick-slip vibration, bit bounce, and backward rotation of drill bits effectively, but also improve their rate of penetration.


Author(s):  
Dapeng Zhao ◽  
Sigbjørn Sangesland

Based on the bit-rock interaction laws, a simple nonlinear 2-dofs mass-spring model is developed to analyze the dynamic cutting process with normal ultrasonic vibration excitation. The study presents a single cutter used in Polycrystalline-Diamond-Compact (PDC) drill bits. Using the 4th Runge-Kutta’s algorithm, numerical simulation found that ultrasonic vibration-induced contact deflection and even loss of contact. The contact friction between the rock and wear-flat (wear surface), which relates to the reaction force, is therefore reduced. This will reduce the wear on the cutter and the force needed to cut the rock. This indicates that the average reduction of friction induced by ultrasonic vibration can be explained by decreasing the average normal force on the cutter-rock wear-flat, rather than changing the friction coefficient.


Sign in / Sign up

Export Citation Format

Share Document