Dynamical Analysis of Drill Bit With Ultrasonic Vibration

2015 ◽  
Author(s):  
Dapeng Zhao ◽  
Sigbjørn Sangesland
Keyword(s):  
Ultrasonic Vibration ◽  
Reaction Force ◽  
Polycrystalline Diamond ◽  
Dynamical Analysis ◽  
Contact Friction ◽  
Rock Interaction ◽  
Drill Bits ◽  
Mass Spring Model ◽  
Mass Spring ◽  
Polycrystalline Diamond Compact

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.

Wear Characteristics of Polycrystalline Diamond Compact Drill Bits in Small Diameter Rock Drilling

1985 ◽  
Vol 107 (4) ◽  
pp. 534-542 ◽  
Author(s):  
C. L. Hough ◽  
B. Das
Keyword(s):  
Small Diameter ◽  
Polycrystalline Diamond ◽  
Wear Test ◽  
Test Results ◽  
Failure Characteristics ◽  
Wear Characteristics ◽  
Drill Bits ◽  
Rotary Speed ◽  
Polycrystalline Diamond Compact ◽  
Single Material

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.

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.

Life Models for Small-Diameter Polycrystalline Diamond Compact Bits in Hard Abrasive Media

1986 ◽  
Vol 108 (4) ◽  
pp. 310-314
Author(s):  
C. L. Hough ◽  
B. Das ◽  
T. G. Rozgonyi
Keyword(s):  
Cutting Speed ◽  
Small Diameter ◽  
Polycrystalline Diamond ◽  
Prediction Equation ◽  
Logarithmic Model ◽  
Drill Bits ◽  
Rate Versus ◽  
Rotary Speed ◽  
Bit Life ◽  
Polycrystalline Diamond Compact

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.

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.

scholarly journals Application of an innovative ridge-ladder-shaped polycrystalline diamond compact cutter to reduce vibration and improve drilling speed

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042093097
Author(s):  
Dou Xie ◽  
Zhiqiang Huang ◽  
Yuqi Yan ◽  
Yachao Ma ◽  
Yuan Yuan
Keyword(s):  
Oil And Gas ◽  
Polycrystalline Diamond ◽  
Rock Breaking ◽  
Drilling Process ◽  
Drilling Speed ◽  
Stick Slip ◽  
Gas Drilling ◽  
Drill Bits ◽  
Element Simulation ◽  
Polycrystalline Diamond Compact

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.

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