scholarly journals A new method for layout layer optimization of long horizontal borehole for gas extraction in overlying strata: a case study in Guhanshan coalmine, China

2021 ◽  
Author(s):  
Wenbing Guo ◽  
Mingjie Guo ◽  
Ruifu Yuan ◽  
Gaobo Zhao ◽  
Guofu Li ◽  
...  
Keyword(s):  
Physical Simulation ◽  
Accumulation Rate ◽  
Engineering Application ◽  
Spatial Location ◽  
Theoretical Method ◽  
Field Application ◽  
Gas Extraction ◽  
Fracture Permeability ◽  
Borehole Stability ◽  
Overlying Strata

Abstract The large emission of pressure-relief gas in coal mining will cause atmospheric greenhouse effect. Arranging long horizontal borehole (LHB) to extract the gas is an effective solution. However, the determination of LHB layout layer in strata has a decisive effect on efficient gas extraction. A "zone-block" theoretical method for determining the LHB layout layer, in present study, was proposed by combining physical simulation test, theoretical analysis and engineering application. Three processes of the method were presented. Firstly, stable fractured subzone (SFSZ) was the optimum zone of the LHB layout based on the analysis of mining-induced fractures distribution and the borehole stability, and spatial location boundaries of the SFSZ in overlying strata were defined. Secondly, the SFSZ was divided into nine-grid blocks, the LHB layout suitability rate of each block were determined according to borehole stability rate, fracture permeability rate and gas accumulation rate. Finally, the LHB drilling could be conducted sequentially according to the layout suitability rate of each block in SFSZ. Field application results show that: the maximum and average amount of pure gas extracted through single borehole arranged in block I can reach up to 5.52 and 2.43 m3·min-1, respectively; and the pure amount in the entire extraction stage of the borehole is 2.53 and 6.69 times of boreholes arranged in blocks II and III, respectively. The proposed method can effectively determine the LHB layout layer in strata, so as to improve the gas extraction efficiency and ensure safe and green mining.

scholarly journals Research on Mechanical Defect Detection and Diagnosis Method for GIS Equipment Based on Vibration Signal

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5507
Author(s):  
Liang He ◽  
Jie Yang ◽  
Ziwei Zhang ◽  
Zongwu Li ◽  
Dengwei Ding ◽  
...  
Keyword(s):  
Experimental Research ◽  
Detection System ◽  
Engineering Application ◽  
Vibration Signal ◽  
Signal Amplitude ◽  
Field Application ◽  
Large Current ◽  
Three Phase ◽  
Diagnosis Method ◽  
Detection And Diagnosis

Gas insulated switchgear equipment (GIS) is widely used in power system, and more attention has been paid to discharge defects than mechanical defects. However, since mechanical defects are a major cause of the failure in GIS, it is of great significance to carry out relevant research on mechanical defects. Detection and diagnosis methods of mechanical defects based on vibration signal are studied in this paper. Firstly, vibration mechanisms of GIS are analyzed. Due to structural differences between single phase insulated type GIS and three phase insulated type GIS, there are big differences in vibration mechanisms between the two types of GISs. Secondly, experimental research on mechanical defects is carried out based on a 110 kV GIS equipment and a self-developed vibration detection system; results show that mechanical defects can be diagnosed by analyzing signal amplitude, frequency spectrum and waveform distortion rate, and a large current is more beneficial for diagnosing mechanical defects. Lastly, field application has been carried out on 220 kV GIS equipment, and a poor contact defect is found, demonstrating that abnormal diagnosis can be realized by method proposed in this paper. Experimental research and field application demonstrate the feasibility and effectiveness of detection and diagnosis method for mechanical defects based on vibration signal and provide experience for subsequent engineering application.

scholarly journals The corresponding relationship between the change of goaf pressure and the key stratum breaking

2019 ◽  
Vol 16 (5) ◽  
pp. 913-925
Author(s):  
Jianlin Xie ◽  
Jialin Xu
Keyword(s):  
Rock Mass ◽  
Internal Pressure ◽  
Load Transfer ◽  
Physical Simulation ◽  
Field Measurements ◽  
Monitoring Methods ◽  
Key Stratum ◽  
Working Face ◽  
Actual Rock ◽  
Overlying Strata

Abstract Existing studies mostly focus on the stress change of coal in front of a goaf, but rarely conduct field monitoring on the internal pressure of a goaf, primarily due to the complex environment and other restrictive conditions of goafs. This paper first used physical simulation to monitor and analyze the internal pressure of goaf and found that goaf pressure presented a stepwise growth with the key stratum breaking. In addition, field measurements were conducted to monitor the goaf pressures of two different working faces. Goaf pressures both presented linear growth with the advance of the working face. According to comparative analysis, there were some differences between the two monitoring methods in terms of the corresponding relationship. This reflects that in the actual rock mass, after the breaking of a key stratum, the loads of the strata under its control are not transferred to the goaf instantaneously and load transfer characteristics are probably related to roof separation distribution characteristics of overlying strata, the bulking characteristics of caved rock mass, lateral stress limitation and other factors. The results of this study will offer some guidance for studies on the movement laws of overlying strata and the load transfer of overlying strata above goafs.

scholarly journals Optimization of the Plastic Area of a Borehole Based on the Gas Extraction Effect and Its Engineering Application

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Kuan Wu ◽  
Shiliang Shi ◽  
Yi Lu ◽  
He Li ◽  
Min Li
Keyword(s):  
Plastic Zone ◽  
Engineering Application ◽  
Gas Extraction ◽  
Key Factors ◽  
Relative Variation ◽  
Factors Affecting ◽  
Gas Expansion ◽  
Zone Radius ◽  
Modified Equation ◽  
Optimal Radius

Gas extraction is most commonly used to control gas disasters in coal mines. The distribution of the plastic zone around a borehole and the sealing quality are key factors affecting gas extraction. In this paper, the plastic zone was simulated by COMSOL, and a theoretical equation of the plastic zone radius was derived. In addition, an antispray hole equipment and the “two plugging and one injection” sealing technology were proposed. The results show that a larger borehole pore size corresponds to a larger plastic zone and larger range of pressure relief of the borehole. The error between the calculated and simulated plastic zone radii is within 1%, and the modified equation is applicable to Puxi mine. The loss and harm caused by borehole spraying are reduced by applying antispray hole equipment. By applying the “two plugging and one injection” sealing technology and phosphogypsum-based self-produced gas expansion paste material to block the borehole, the sealing quality is improved and an accurate gas mixing flow, pure flow, and concentration were obtained. As the plastic zone enlarges, the gas extraction flow gradually increases with, but the relative variation of flow first increases and subsequently decreases. Considering the safety and economy of construction, the optimal radius of the plastic zone is 64.9 mm.

Discussion about Application of Composite Repair Technique in Pipeline Engineering

2011 ◽  
Vol 311-313 ◽  
pp. 185-188 ◽  
Author(s):  
Wei Feng Ma ◽  
Jin Heng Luo ◽  
Ke Cai
Keyword(s):  
Fiber Composite ◽  
New Technology ◽  
Engineering Application ◽  
Development Trend ◽  
Indicator System ◽  
Field Application ◽  
Clear Understanding ◽  
Composite Repair ◽  
Steel Pipeline ◽  
Reinforced Steel

Fiber composite repair reinforced steel pipeline structure is new technology developed in the nineties of the twentieth century, the technology is highly regarded in the world, has already become a development trend of repair reinforced steel pipeline structure. This paper reviews the problem existing, such as interfacial debonding, layered, empty drum, blank holder and no or incomplete sealing in the repair and reinforcement technique of composite during engineering application. The corresponding formation reason is primarily analyzed according to the construction experience. On the basis, it is pointed out that it is very necessary to establish the check and evaluating indicator system of the field construction acceptance process and field application effect of the fiber composite used in repairing and reinforcing the pipeline, which of the aim is to improve the repair and reinforcement quality and to obtain a full and clear understanding about the repair status and effect of the repair points in the repaired service pipeline.

Calculation Method on Bearing Capacity of Anchor Bolt of Transmission Line Tower Foundation Considering Influence of Horizontal Force

2012 ◽  
Vol 170-173 ◽  
pp. 327-330
Author(s):  
Qiang Cui ◽  
Xian Long Lu
Keyword(s):  
Transmission Line ◽  
Bearing Capacity ◽  
Engineering Application ◽  
Theoretical Method ◽  
Horizontal Force ◽  
Transmission Tower ◽  
Strength Theory ◽  
Anchor Bolt ◽  
Uplift Force ◽  
The Third

Anchor bolt which is one of the most important component connecting foundation and transmission tower bears the force transmitted from superstructure. At present, in the conventional design method, uplift force is only included, however, the influence of horizontal force on bearing capacity of anchor bolt is neglected. Thus, a theoretical method on obtaining bearing capacity of anchor bolt is proposed for the first time based on the third strength theory in this paper, in which the influence of horizontal force is considered. According to the third strength theory, the calculation results of bearing capacity of anchor bolt under different force are obtained. It can be seen that the cross-section area of single anchor bolt shows linear increase with the increment of vertical uplift force, at the same time, the influence of horizontal force to bearing capacity of anchor bolt is more significant with the addition of the ratio of horizontal force to uplift force, which should be attached enough attention in engineering application. And the conclusion achieved in this work can provide valuable guidance for anchor bolt design of the transmission line project.

scholarly journals Three-Dimensional Physical Simulation and Control Technology of Roof Movement Characteristics in Non-Pillar Gob-Side Entry Retaining by Roof Cutting

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Xinzhu Hua ◽  
Guanfeng Chang ◽  
Xiao Liu ◽  
Bingjun Sun ◽  
Sen Yang ◽  
...  
Keyword(s):  
Simulation Experiment ◽  
Physical Simulation ◽  
Three Dimensional ◽  
Engineering Application ◽  
Key Strata ◽  
Rock Structure ◽  
Geological Conditions ◽  
Support Resistance ◽  
And Migration ◽  
Roof Deformation

An overlying rock structure plays a key role in controlling the roof deformation of nonpillar gob-side entry retaining by roof cutting. On the bases of the actual geological conditions of II 632 Haulage Roadway at the Hengyuan coal mine, a similar three-dimensional simulation experiment of roof precutting is conducted. Thereafter, the caving characteristics and migration law of the roof strata in the strike and dip directions are obtained. Moreover, the roof of the retained roadway and key strata of the goaf can form a hinge structure of the key blocks. By monitoring the deformation of the surrounding rock and stress distribution of the roof, the skew deformation characteristics of roadway roof are obtained. By observing the borehole peeping technology, the roof subsidence near the goaf is determined to be greater than that of the solid coal side, and the roof subsidence of the gob-side entry retained by roof cutting is greater than that of the floor heave and two sides approaching. Results of the three-dimensional similar simulation experiment indicate that the mechanical structure model of the key block of the retained roadway roof is constructed, and the mechanical analytical solution of the required support resistance of the retained roadway roof is obtained. This study proposes the constant resistance and large deformation anchor cable reinforcement support method to control the roof deformation of the retaining roadway. Through engineering application, the maximum value of the roof and floor movement of the retained roadway is stable at approximately 650 mm. The retained roadway can meet the demand of the next mining face.

The New Technology of Hydraulic Fracturing Soft Coal Rock Permeability Improvement

2014 ◽  
Vol 1030-1032 ◽  
pp. 1255-1259 ◽  
Author(s):  
Xue Xi Chen ◽  
Yan Ke Zhang ◽  
Yong Xu ◽  
Rui Qing Bi
Keyword(s):  
Coal Seam ◽  
New Technology ◽  
Water Injection ◽  
Injection Pressure ◽  
Field Application ◽  
Good Effect ◽  
Gas Extraction ◽  
Soft Coal ◽  
Coal Rock ◽  
Soft Coal Seam

According to the low intensity, good plasticity in soft coal seam, the effect of direct fracturing to increase permeability was not ideal, the new technology of hydraulic fracture soft coal rock was proposed, which increased coal seam permeability. Its technical principles and characteristics were researched. Water injection pressure was analyzed, including injection time, parameters of the technology and so on. Field application experiment and effect of inspection were conducted. The results showed that the concentration of gas extraction increased 4.3 times, and the gas extraction flow increased 6.2times. The technology has a good effect of fracturing and advantages in enlarging the released area and decreasing diffusion seepage resistance of coal seam. Most important, the technology has broad application prospects in soft coal seam.

Borehole Stability Analysis and its Application in Xujiahe Formation of ZJ Block

2012 ◽  
Vol 524-527 ◽  
pp. 1359-1362
Author(s):  
Kan Hua Su ◽  
Hong Liu ◽  
Jun Wang
Keyword(s):  
Mechanical Test ◽  
Drilling Fluid ◽  
Stress Test ◽  
Field Application ◽  
Wellbore Stability ◽  
Test Method ◽  
Borehole Stability ◽  
Xujiahe Formation ◽  
Ground Stress ◽  
Rock Mechanical Test

The mainly borehole problems are sticking (collapse) and circulation loss in Xujiahe formation of ZJ block, so the drilling rate is very low. In order to improve the penetration of rate of ZJ block, the rock mechanical test method, ground stress test method, well history statistics method, and logging data analysis method were adopted. The borehole stability mechanism of xujiahe formation was analyzed. Combined with the drilling fluid experimental evaluation, the measures of improve wellbore stability of xujiahe formation was Proposed. Field application tests show that, the borehole problems and its processing time are greatly reduced using those proposed measures. The penetration of rate in the Xujiahe formation of test well increased 20-30%, and the application effect is obvious.

scholarly journals A Theoretical Study on the Hydrodynamics of a Zero-Pressurized Air-Cushion-Assisted Barge Platform

2020 ◽  
Vol 8 (9) ◽  
pp. 664
Author(s):  
Fengmei Jing ◽  
Li Xu ◽  
Zhiqun Guo ◽  
Hengxu Liu
Keyword(s):  
Coupling Effect ◽  
Low Cost ◽  
Engineering Application ◽  
Theoretical Method ◽  
Hydrodynamic Performance ◽  
Irregular Waves ◽  
Floating Body ◽  
Motion Response ◽  
Air Cushion ◽  
Heave Motion

Thebarge platform has the advantages of low cost, simple structure, and reliable hydrodynamic performance. In order to further improve the hydrodynamics of the barge platform and to reduce its motion response in waves, a zero-pressurized air cushion is incorporated into the platform in this paper. The pressure of the zero-pressurized air cushion is equal to atmospheric pressure and thus does not provide buoyancy to the platform. As compared to the conventional pressurized air cushion, the zero-pressurized one has advantages of less air leakage risk. However, due to the coupling effect on the interface between water and air cushion, the influence of the gas inside the air cushion on the performance of the floating body has become a difficult problem. Based on the boundary element method, the motion response of the zero-pressurized air-cushion-assisted barge platform under regular and irregular waves is calculated and analyzed in the paper. Compared with the barge platform without air cushion, numerical results from the theoretical method show that in regular waves, the air cushion could significantly reduce the amplitude of heave and pitch (roll) response of the round barge platform in the vicinity of resonance. In irregular waves, the air cushion also observably reduces the pitch (roll) motion, though amplifies the heave motion due to the transfer of heave resonance frequency. Thetheoretical study demonstrates that the zero-pressurized air cushion can reduce the seakeeping motion of barge platforms in high sea states, but might also bring negative effects to heave motion in low sea states. One should carefully design the air cushion for barge platforms according to the operating sea states to achieve satisfactory hydrodynamic performance in engineering application.

Sign in / Sign up

Export Citation Format

Share Document