Determination of sealing depth of in-seam boreholes for seam gas drainage based on drilling process of a drifter

2016 ◽  
Vol 210 ◽  
pp. 115-123 ◽  
Author(s):  
Kai Zhang ◽  
Kai Sun ◽  
Bangyong Yu ◽  
Ranjith Pathegama Gamage
Keyword(s):  
Drilling Process ◽  
Gas Drainage

scholarly journals Determination of Long Horizontal Borehole Height in Roofs and its Application to Gas Drainage

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2647
Author(s):  
Gang Wang ◽  
Cheng Fan ◽  
Hao Xu ◽  
Xuelin Liu ◽  
Rui Wang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Model ◽  
Fracture Zone ◽  
Coalbed Methane ◽  
High Efficiency ◽  
Gas Drainage ◽  
Methane Drainage ◽  
Working Face ◽  
Variation Characteristics

Accurately determining the height of the gas-guiding fracture zone in the overlying strata of the goaf is the key to find the height of the long horizontal borehole in the roof. In order to determine the height, in this study we chose the 6306 working face of Tangkou Coal Mine in China as a research example and used both the theoretical model and discrete element method (DEM) numerical simulation to find the height of the gas-guiding fracture zone and applied the height to drill a long horizontal borehole in the roof of the 6303 working face. Furthermore, the borehole was utilized to deep into the roof for coalbed methane drainage and the results were compared with conventional gas drainage measures from other aspects. The height of the gas-guiding fracture zone was found to be 48.57 m in theoretical model based on the bulk coefficient and the void ratio and to be 51.19 m in the DEM numerical simulation according to the temporal and spatial variation characteristics of porosity. Taking both the results of theoretical analysis and numerical simulation into consideration, we determined that gas-guiding fracture zone is 49.88 m high and applied it to drill a long horizontal borehole deep into the roof in the 6303 working face field. Compared with conventional gas drainage measures, we found that the long horizontal borehole has the high stability, high efficiency and strong adaptability for methane drainage.

Modeling the Vibratory Drilling Process

1999 ◽  
Author(s):  
Stephen A. Batzer ◽  
Alexander M. Gouskov ◽  
Sergey A. Voronov
Keyword(s):  
Rotational Velocity ◽  
Time Lag ◽  
Chip Thickness ◽  
Cutting Conditions ◽  
Model Parameters ◽  
Drilling Process ◽  
Workpiece Material ◽  
Velocity Amplitude ◽  
The Stability

Abstract The dynamic behavior of deep-hole vibratory drilling is analyzed. The mathematical model presented allows the determination of axial tool and workpiece displacements and cutting forces for significant dynamic system behavior such as the entrance of the cutting tool into workpiece material and exit. Model parameters include the actual rigidity of the tool and workpiece, time-varying chip thickness, time lag for chip formation due to tool rotation and possible disengagement of drill cutting edges from the workpiece due to tool and/or workpiece axial vibrations. The main features of this model are its nonlinearity and inclusion of time lag differential equations which require numeric solutions. The specific cutting conditions (feed, tool rotational velocity, amplitude and frequency of forced vibrations) necessary to obtain discontinuous chips and reliable removal are determined. The stability conditions of excited vibrations are also investigated. Calculated bifurcation diagrams make it possible to derive the domain of system parameters along with the determination of optimal cutting conditions.

scholarly journals A Study on Drilling Process Control by Intelligent Machine Tools. (1st Report). Determination of Cutting Condition for Drilling.

2000 ◽  
Vol 66 (8) ◽  
pp. 1270-1274 ◽  
Author(s):  
Tomonori SATI ◽  
Yoshiaki KAKINO ◽  
Atsushi MATSUBARA ◽  
Makoto FUJISHIMA ◽  
Isao NISHIURA ◽  
...  
Keyword(s):  
Process Control ◽  
Machine Tools ◽  
Cutting Condition ◽  
Drilling Process ◽  
Intelligent Machine

scholarly journals Influence of Long Boreholes Layout and Drilling Length on Gas Drainage Based on Multifield Coupling Model of Gas-Bearing Coal

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Renjun Feng
Keyword(s):  
Coupling Model ◽  
Specific Reference ◽  
Gas Migration ◽  
Quantitative Characterization ◽  
Gas Drainage ◽  
Drainage Time ◽  
Working Face ◽  
Drainage Effect ◽  
Gas Bearing

Gas drainage through long seam boreholes is an effective method to prevent gas disasters in coal mines. In this paper, a multifield coupling model of gas migration in gas-bearing coal was first established. Then, a quantitative characterization method of gas drainage effect was put forward. Finally, the extraction effect of long boreholes was obtained under different layouts and drilling lengths. The research results show that, under the arrangement of long boreholes along the seam, the gas pressure around the borehole decreases significantly with the extraction time. There is no extraction blank in the middle of the working face. However, it is easy to cause uneven gas drainage in the combined arrangement of the long boreholes along the seam and the penetrating boreholes. Furthermore, it is found that the drainage volume of the long boreholes along the seam is similar to that of the joint layout under the same drainage time. As the length of the borehole increases, the influencing range of gas drainage increases. When the borehole lengths are 150 m and 240 m, the drainage volumes are about 1.31 and 2.50 times that of the 90 m boreholes, respectively. The research achievements could provide a specific reference for the layout of long boreholes along the bedding and the determination of reasonable parameters for gas drainage on site.

Determination of the Optimal Path of Three Axes Robot Using Genetic Algorithm

2019 ◽  
Vol 44 ◽  
pp. 135-149
Author(s):  
Sid Ahmed Dahmane ◽  
Abdelkader Megueni ◽  
Abdelwahab Azzedine ◽  
Abdelkader Slimane ◽  
Abdelkader Lousdad
Keyword(s):  
Optimal Path ◽  
Cutting Tools ◽  
Machining Process ◽  
Work Piece ◽  
Drilling Process ◽  
Genetic Optimization ◽  
Machining Time ◽  
Planning And Scheduling ◽  
Cylindrical Holes

Drilling is a chip machining process widely used in manufacturing .The term drilling includes all methods for making cylindrical holes in a work piece with chip cutting tools. There are many applications where drilling is used, such as drilling holes in PCBs. Robotic systems are used today to perform the drilling process. A problem that affects the use of these systems is the drilling sequence, as there are usually a number of points to visit. The determination of the drilling sequence is similar to the problem of synchronization of movement and travel time. The main objective is to optimize the time and trajectory of the three axes robot equipped with an automatic drill that seeks the best performance. In this paper, we have built a genetic optimization and problem solving algorithms to shorten the machining time to drill a given group of holes and reduce machining costs in order to improve the efficiency of the machining process as well robotic machining with three axes without degradation of the precision of the movement. The results of the experiments show that the proposed approach is feasible and practical. It is particularly useful in planning and scheduling systems for real-time manufacturing processes.

scholarly journals Improvement of Gas Drainage Efficiency via Optimization of Sealing Depth of Cross-Measure Boreholes

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Pu Li ◽  
Zhiheng Cheng ◽  
Liang Chen ◽  
Hongbing Wang ◽  
Jialin Cao
Keyword(s):  
Stress Concentration ◽  
Drainage System ◽  
Stress Concentration Zone ◽  
Concentration Zone ◽  
Air Leakage ◽  
In Situ Tests ◽  
Gas Drainage ◽  
Drainage Borehole

The sealing depth of a gas-drainage borehole is critically important as it directly affects the efficiency of the whole drainage system. In order to determine the shortest reasonable sealing depth, in this paper, a theoretical drainage model using different sealing depths was proposed. Based on theoretical analysis presented, two parts of the fractures system surrounding the drainage borehole were proposed, i.e. the fractures induced by roadway excavation and the fractures induced by borehole drilling. A series of geological in-situ tests and simulations research were conducted to determine the stress and fracture distributions in the surrounding rock of the borehole. The depths of crushing zones, plastic zones and stress concentration zones were determined as 5 m, 2 m and 12 m, respectively. Meanwhile, stress simulation shows that the depth of the stress concentration zone was 12 m from the roadway wall and the stress peak was located at the depth of 8 m, which can be verified by the results of drilling penetration velocity analysis. To determine the optimum sealing depth, gas drainage holes with different sealing depths were drilled in the field. The field results revealed that the crushing zones were the main area for air leakage, and the stress concentration induced by roadway excavation assisted in the reduction of air leakage. Therefore, the optimized sealing depth should both cover the plastic zone and the stress concentration zone. The research achievements can provide a quantitative method for the determination of optimum sealing depth in cross-measure drainage boreholes.

scholarly journals Estimation of serpentinite rock mass strength of Placetas - Cuba underground gold mine deposit

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Adeoluwa O Oluwaseyi ◽  
Olawale O Ajibola
Keyword(s):  
Rock Mass ◽  
Technical Information ◽  
Geological Strength Index ◽  
Drilling Process ◽  
Gold Mine ◽  
Well Log ◽  
Strength Index ◽  
Global Strength ◽  
Type Of Failure

This study estimated the strength of the serpentinite rock mass of the underground gold mine “Oro Descanso” Placetas, Cuba. The rock mass was classified into its lithological group of massive, sheared serpentinite rocks and gabbros. The geo-technical information from the well log data obtained during drilling process (geological logs). The structural analysis was carried out through field observation and quantified by Geological Strength Index (GSI) of average values for massive serpentinite 60, sheared serpentinite 38 and gabbros 78. The generalized Hoek-Brown criterion with software programme, Rocklab 1.0, 2004 version was employed for the analysis and the determination of the rock mass local compressive strength (massive serpentinite = 1.733Mpa; sheared serpentinite = 0.464Mpa; gabbros = 10.354Mpa) and the global strength (massive serpentinite = 6.561Mpa, sheared serpentinite = 5.657Mpa and gabbros = 22.547Mpa). These estimated values characterize brittle type of failure mode and thus supports are recommended.

scholarly journals Thermo-mechanical stresses distribution on bone drilling: Numerical and experimental procedures

2017 ◽  
Vol 233 (4) ◽  
pp. 637-646 ◽  
Author(s):  
Maria G Fernandes ◽  
Elza M Fonseca ◽  
Renato N Jorge
Keyword(s):  
Numerical Model ◽  
Bone Tissue ◽  
Experimental Tests ◽  
Mechanical Stresses ◽  
Surrounding Tissue ◽  
Drilling Process ◽  
Bone Drilling ◽  
Drilling Parameters ◽  
Drilling Conditions

In bone drilling, the temperature and the level of stresses at the bone tissue are function of the drilling parameters. If certain thresholds are exceeded, irreversible damages may occur on the bone tissue. One of the main challenges in the drilling process is to control the associated parameters and even more important, to avoid the surrounding tissue damage. In this study, a dynamic numerical model is developed to determine the thermo-mechanical stresses generated during the bone drilling, using the finite element method. The numerical model incorporates the geometric and dynamic characteristics involved in the drilling processes, as well the developed temperature inside the material. The numerical analysis has been validated by experimental tests using polyurethane foam materials with similar mechanical properties to the human bone. Results suggest that a drill bit with lower drill speed and higher feed rate can reduce the strains and stresses in bone during the drilling process. The proposed numerical model reflected adequately the experimental results and could be useful in determination of optimal drilling conditions that minimise the bone injuries.

Metrological Determination of Torque for Monitoring During Composite Drilling Process

2021 ◽  
Vol 396 (1) ◽  
pp. 2000325
Author(s):  
Claudiu Bisu ◽  
George Dinu ◽  
Miron Zapciu
Keyword(s):  
Drilling Process ◽  
Composite Drilling
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