Nonlinear Dynamics Research between Drill Pipe and Coal Hole Wall during Gas Extraction Drilling

Author(s):  
Xiaoming Han ◽  
Chenxu Luo ◽  
Qiangqiang Zhang

This paper analyzes the impact of gas drainage borehole drilling rod vibration phenomena stability.Taking 100m hole depth in underground coal mine as an example, the dynamic simulation analysis of the underground gas drainage drilling rod was carried out by using the ANSYS finite element dynamic analysis module LS-DYNA method.According to the collision course between the drill pipe and the coal hole wall, the Lagrange algorithm is introduced to analyze the stress change of drill pipe in the collision course of 98mm, 108mm, 118mm and 128mm. The failure mechanism of drill pipe fatigue fracture and hole wall instability caused by the collision between drill pipe and coal hole is analyzed. The results show that the stress caused by the impact of drilling speed, drilling pressure and coal hole diameter is larger than that caused by the collision between drill pipe and coal wall.

Author(s):  
Xiaoming Han ◽  
Zhanxu Tie ◽  
Dongsheng Li ◽  
Longlie Zhang ◽  
Chaoyang Shi
Keyword(s):  

2021 ◽  
Vol 257 ◽  
pp. 03076
Author(s):  
Dayong Tang ◽  
Yi Tang ◽  
Zhengyong Duan ◽  
Wannian Lei ◽  
Xiaolong He ◽  
...  

According to the characteristics of high efficiency and high hole forming rate of the triangular-shaped drill pipe in the process of drilling in soft outburst coal seam, the slag discharge model of annular gap between the triangular-shaped drill pipe and hole wall is established by using the basic theory of computational fluid dynamics.Using the finite volume element method, the flow field characteristics of the annular flow area between drill pipe and hole wall are analyzed.Through the numerical simulation analysis, the velocity fluctuation effect of the annular flow field of the slag removal model is put forward, that is, the velocity fluctuation zone is formed between the sides of the arc edge of the triangular-shaped drill pipe, which causes the precipitated coal cinder to rise under the vortex action of the flow field, and is quickly discharged out of the hole under the coordination of the axial velocity, which effectively improves the slag removal efficiency and pore forming rate of the drill pipe.Finally, the comparative test of the triangular-shaped drill pipe and wide-blade spiral drill pipe was carried out in the soft outburst coal seam of 31021 lower auxiliary roadway in a mine. The drilling depth was increased by 19.4%, the hole forming rate was increased by 17.4%, and the drilling efficiency was increased by 26.4%. There was no drill drop and broken phenomenon.


2020 ◽  
Vol 20 (3) ◽  
pp. 975-995
Author(s):  
Jianwei Wang ◽  
Shixuan Wang ◽  
Haoyu Le ◽  
Maoxin Ge

To reduce the failure probability of gas drainage drilling holes in coal mines, a new modeling method of gas drainage drilling machine is presented. Firstly, each drill pipe is regarded as a flexible body, and the Lagrange’s equation of second kind is used to model it. Secondly, the joint of drill bit, hole wall and drill pipe are regarded as rigid bodies, and the Newton-Euler method is used to model it. Thirdly, the rigid-flexible coupling multi-body dynamic model of drilling rig-drill pipe-hole wall system in medium and short horizontal section of soft coal seam is established by using relative node coordinate method, and the time complexity and operation complexity of modeling are reduced by using ADAMS macro program. Finally, the finite element method is used to discretize the model, and the virtual prototyping technology is used to solve the mathematical model. The simulation results show that the coupling of friction and vibration does not necessarily increase the probability of drilling failure, but sometimes reduces the amplitude of vibration. Compared with the length of each drill pipe, the influence of drilling depth on the system is greater, and the bit-bounce behaviours is more likely to occur in the deep hole. The operating frequency range of the drilling rig is 6.9E-3 to 2.1E+4Hz. When the length of the drill pipe is constant, the natural frequency of the system increases with the increase of the order, while the natural frequency of the deep hole section is almost unaffected by the order. In practical engineering, the vibration excitation of the actuator should be controlled to avoid the natural frequency. Meanwhile, the modal frequency should be avoided as far as possible to reduce the vibration and the failure probability of drilling holes. The model can simulate a series of dynamic responses of drilling rig system in drilling process, and provide theoretical support for subsequent multi-factor coupling modeling.


2020 ◽  
Vol 90 (3) ◽  
pp. 30502
Author(s):  
Alessandro Fantoni ◽  
João Costa ◽  
Paulo Lourenço ◽  
Manuela Vieira

Amorphous silicon PECVD photonic integrated devices are promising candidates for low cost sensing applications. This manuscript reports a simulation analysis about the impact on the overall efficiency caused by the lithography imperfections in the deposition process. The tolerance to the fabrication defects of a photonic sensor based on surface plasmonic resonance is analysed. The simulations are performed with FDTD and BPM algorithms. The device is a plasmonic interferometer composed by an a-Si:H waveguide covered by a thin gold layer. The sensing analysis is performed by equally splitting the input light into two arms, allowing the sensor to be calibrated by its reference arm. Two different 1 × 2 power splitter configurations are presented: a directional coupler and a multimode interference splitter. The waveguide sidewall roughness is considered as the major negative effect caused by deposition imperfections. The simulation results show that plasmonic effects can be excited in the interferometric waveguide structure, allowing a sensing device with enough sensitivity to support the functioning of a bio sensor for high throughput screening. In addition, the good tolerance to the waveguide wall roughness, points out the PECVD deposition technique as reliable method for the overall sensor system to be produced in a low-cost system. The large area deposition of photonics structures, allowed by the PECVD method, can be explored to design a multiplexed system for analysis of multiple biomarkers to further increase the tolerance to fabrication defects.


Author(s):  
R.R. Barton ◽  
L.W. Schruben ◽  
J.C. Ford ◽  
D. Hopkins ◽  
D. Goldsman ◽  
...  

2013 ◽  
Vol 805-806 ◽  
pp. 334-337
Author(s):  
Shi Wei Su ◽  
You Wei Zhou ◽  
Wei Xiong

Analysis compares the direct access to a single set of wind power systemTwo groups of wind farm access system directlyMultiple sets of wind farm access system directly And Multiple sets of wind dispersion access system's impact on power system transient stability. And compare the simulation results, Concluded that wind farm access capacity and its topology structure's influence on system transient stability.


2021 ◽  
pp. 94-103
Author(s):  
Jiangtao Du ◽  
Steve Sharples

The deposition of air pollutants on glazing can significantly affect the daylight transmittance of building fenestration systems in urban areas. This study presents a simulation analysis of the impact of air pollution and glazing visual transmittance on indoor daylight availability in an open-plan office in London. First, the direct links between glazing visual transmittance and daylighting conditions were developed and assessed. Second, several simple algorithms were established to estimate the loss of daylight availability due to the pollutant deposition at the external surface of vertical glazing. Finally, some conclusions and design strategies to support facade planning at the early design stage of an urban building project were developed.


2021 ◽  
pp. 095745652110307
Author(s):  
Kangping Gao ◽  
Xinxin Xu ◽  
Ning Shi ◽  
Shengjie Jiao

In the process of drilling and coring by the rock-breaking rig, the drill rod is affected by the intermittent impact force, which reduces the efficiency of the rig to break the rock and increases the cost of the drilling and coring. Therefore, it is very important to improve the impact resistance of the drill pipe during the rock-breaking process. To achieve this goal, a flexible design of the drill pipe was carried out, and a dynamical model of the drilling rig based on a series elastic actuator was established. Considering the dynamic performance of the system, a torque feedforward link is introduced and a control model based on the force source is established. The influence of the equivalent inertia of the transmission system and the series elastic actuator damping coefficient on the system stability was analyzed by drawing the frequency domain characteristic curve of the system. By using the control and Simulink simulation software, the electromechanical simulation of the model is carried out, and the torque step tracking response of the system is obtained. A torque feedforward link is introduced to establish the control model of the system based on force source. Through dynamic simulation software ADAMS, dynamic and static impact simulation experiments were carried out on the system. The results show that when a force of 200 N is applied to the output end of the drill pipe in the tangential direction, the maximum moments received by the joint under static and dynamic environments are 34.1 N·m and 57.9 N·m, respectively. When the impact force disappears, the time required for the flexible drill pipe to reach a stable state is only 0.15 s, which verifies that the series elastic actuator–based drill pipe model can alleviate the impact of the external environment and protect the internal structure of the rig.


2014 ◽  
Vol 501-504 ◽  
pp. 578-582
Author(s):  
Liang Hsu ◽  
Ming Long Hu ◽  
Jun Zhi Zhang

Considering secondary load, simulate the axial compression process of reinforced concrete square columns strengthened with igneous rock fiber reinforced polymer with Abaqus. Make a comparison between the simulation result and experimental result. The finite-element model can simulate the experiment preferably. And the impact of lagged strain is very obvious.


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