Evaluation Method Of Compressibility Of Shale Gas Reservoir In Consideration Of The Influence Of Fracture Toughness,
2019
State Key Laboratory of Coal Mine Disaster Dynamics and Control of Chongqing University, Chongqing 400044, China; State and Local Joint Engineering Laboratory of Methane Drainage in Complex Coal Gas Seam of Chongqing University, Chongqing 400044, China
Evaluation Method Of Compressibility Of Shale Gas Reservoir In Consideration Of The Influence Of Fracture Toughness, Zhang Chenqing, Xu Jiang, Peng Shoujian, Yan Fazhi, Wu Bin, Yue Yuqing
Coal Geology & Exploration
Compressibility is an important basis for measuring the response of shale gas reservoirs to hydraulic fracturing. Currently, the brittleness index commonly used for shale compressibility has been evaluated. However, in practice, there are problems in which the brittleness index is similar and the actual fracturing effect is far different. In order to make up for the lack of brittleness index for the evaluation of compressibility of shale gas reservoirs, this study incorporated critical mechanical energy release rate in consideration of the influence of fracture toughness, and defined the average critical mechanical energy release rate of the integrated modes I and …
Test Of The Influence Of Dynamic Water Grouting Diffusion Radius Of Fractures In Rock,
2019
School of Architecture and Civil Engineering, Xi'an University of Science and Technology, Xi'an 710054, China
Test Of The Influence Of Dynamic Water Grouting Diffusion Radius Of Fractures In Rock, Gu Shuancheng, Sun Guanlin, Su Peili, Li Jinhua
Coal Geology & Exploration
Water-cement ratio and grouting pressure are the key factors in the design of hydrodynamic grouting. In this paper, based on the self-designed simulated fissure hydrodynamic grouting indoor test platform, the dynamic water grouting test was carried out, the diffusion mode of the slurry in fractures was discussed. The relationship among the diffusion radius of pure cement slurry, the grouting pressure and water-cement ratio was analyzed. The experimental results were verified by computational fluid dynamics software. The results show that the diffusion mode of the slurry is partition diffusion. When the grouting pressure is constant, the diffusion radius is inversely proportional …
Lbfgs Csamt 1d Inversion Of Limited Memory Based On Boundary Constraint And Its Application,
2019
Huabei Oil Reservoir, CNPC, Renqiu 062552, China
Lbfgs Csamt 1d Inversion Of Limited Memory Based On Boundary Constraint And Its Application, Tang Chuanzhang, Cheng Jianzhong, Yan Liangjun, Feng Guangye, Zhou Lei, Xu Fengjiao
Coal Geology & Exploration
CSAMT is characterized by time-consuming calculation and low accuracy. The conventional inversion method has simple boundary processing, needs big memory, it is difficult to have accurate search direction, influencing severely the effect of inversion. In order to achieve rapid and high-precision forward modeling of CSAMT, to improve the boundary processing method, to reduce memory usage, to optimize the searching direction to reduce the times of iterative inversion, LBFGS CSAMT 1D inversion method based on boundary constraint and limited memory was proposed. Firstly in CSAMT forward modeling, double-precision and parallel algorithm was adopted, realizing rapid and high-precision calculation of the horizontal …
Calibration And Experiment Of Mine Electromagnetic Lwd Gamma Logging Tool,
2019
Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
Calibration And Experiment Of Mine Electromagnetic Lwd Gamma Logging Tool, Wang Xiaolong, Jiang Bici, Wang Kaibin
Coal Geology & Exploration
In order to effectively identify coal seam, roof and floor, mine electromagnetic LWD gamma logging tool was developed for directional drilling in coal mine. The calibration coefficient of the instrument can be obtained by natural gamma logging scale, and various measurement curves of mine electromagnetic LWD gamma logging tool can be obtained by standard well test and crossing borehole test in coal mine. Through comparing with the gamma curve of standard well and analyzing the geological data of the crossing borehole, the measurement result accuracy of mine electromagnetic LWD gamma logging tool is verified. The application test in underground coal …
Development Of Impact Screw Motor,
2019
Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
Development Of Impact Screw Motor, Wang Siyi, Li Quanxin, Liu Jianlin, Zhao Jiangpeng, Yang Dongdong
Coal Geology & Exploration
Aiming at the problems of low efficiency and high consumption of bits and drilling tools in drilling hard rock with conventional single bend screw motor, an impact screw motor is developed by adding an impact mechanism between the universal shaft of a common screw motor and the drill bit. The impact screw motor has dual functions of impact and orientation. The structure and the working principle of impact mechanism, the design of key components and the characteristics of the impact screw motor are introduced. Laboratory tests were carried out on the φ89 mm impact mechanism, and the peak impact …
Table Of Contents,
2019
China Coal Technology and Engineering Group (CCTEG)
Trilinear Chart Classification Method Of Mine Water Hazard Type Based On Factors Of Water Recharge,
2019
Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China; Shaanxi Key Laboratory of Prevention and Control Technology for Coal Mine Water Hazard, Xi'an 710077, China
Trilinear Chart Classification Method Of Mine Water Hazard Type Based On Factors Of Water Recharge, Hu Weiyue, Zhao Chunhu
Coal Geology & Exploration
The results of the classification of hydrogeological types in coal mines are relatively inadequate to reflect the characteristics of water hazards such as water sources and water inrush channels. It is not very instructive to carry out water control work in coal mines starting from the basic elements of mine water hazard formation, this paper analyses the characteristics and harm degree of mine water hazard under different types of mine water sources, water inrush channels and their combination conditions, the water inrush source can be divided into 4 types according to its water-rich degree and supply capacity:weak supply of slow …
Analytical Solution For Surrounding Rock Of Circular Roadway Based On Generalized Smp Criterion Considering Seepage And Dilatancy,
2019
School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory of Urban Underground Space Engineering(University of Science and Technology Beijing), Beijing 100083, China; Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mines(University of Science and Technology Beijing), Beijing 100083, China
Analytical Solution For Surrounding Rock Of Circular Roadway Based On Generalized Smp Criterion Considering Seepage And Dilatancy, Pan Jiliang, Ren Fenhua
Coal Geology & Exploration
Based on the generalized spatially mobilized plane(SMP) criterion, considering intermediate principal stress, pore water pressure and dilatancy characteristics of surrounding rock, an ideal elastic-plastic model of roadway surrounding rock is established. According to the elastic-plastic theory, the unified analytical solutions of stress field, displacement field and radius of plastic zone under seepage flow are obtained. Then, the stress distribution of surrounding rock and the radius of plastic zone calculated by SMP criterion are compared with those calculated by Mohr-Coulomb(M-C) criterion, and the influencing factors such as pore water pressure and dilatancy angle of surrounding rock are analyzed. It is shown …
Identification Model Of The Independence Right-Fuzzy Variable Theory Of Water Inrush Source,
2019
College of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing 100083, China; National Engineering Research Center of Coal Mine Water Hazard Controlling, Beijing 100083, China
Identification Model Of The Independence Right-Fuzzy Variable Theory Of Water Inrush Source, Dong Donglin, Li Xiang, Lin Gang, Bian Jianling, Cao Chenglong, Wu Heng
Coal Geology & Exploration
In the process of coal mining, mine water hazard accidents occur frequently. In order to find out the water source of mine water inrush quickly and accurately, and reduce the harm caused by mine water inrush to coal mine production, taking Zhaogezhuang mine as an example, and the method of combining independent weight coefficient with fuzzy variable theory was used to select six kinds of hydrochemical indexes of Na+, Ca2+, Mg2+, Cl-, SO42- and HCO3-, 20 sets of water sample data of Zhaogezhuang mine were analyzed and …
Micro Ct-Based Meticulous Characterization Of Porosity Evolution Of Coal In The Process Of Biodegradation,
2019
School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China
Micro Ct-Based Meticulous Characterization Of Porosity Evolution Of Coal In The Process Of Biodegradation, Dong Zhiwei, Guo Hongyu, Xia Daping, Liu Xile, Bai Yang, Zhao Guojun
Coal Geology & Exploration
To explore the bio-permeability enhancing effect via methanogen treatment on different rank coals after anaerobic fermentation, micro-CT was used to analyze the change characteristics of pore structure of coal before and after biodegradation. At the same time, the adsorption characteristics of methanogens on the coal surface after anaerobic biodegradation were observed by scanning electron microscopy to analyze the reasons for the effect difference of biological transformation of different rank coals. The results show that the porosity and total throat length of the coal samples biodegraded increase and the connectivity of the pores is enhanced, it is indicated that coal samples …
Comprehensive Outburst Prevention Technology Of Outburst-Prone Coal Seam Uncovered By Crossdrift In Hongshan Coal Mine,
2019
School of Mines, Liaoning Technical University, Fuxin 123000, China; State Key Laboratory of Coal Resources and Safe Mining, Xuzhou 221008, China; State Key Laboratory of Water Resource Protection and Utilization in Coal Mining, Beijing 100011, China
Comprehensive Outburst Prevention Technology Of Outburst-Prone Coal Seam Uncovered By Crossdrift In Hongshan Coal Mine, Wang Beifang, Liang Bing, Zhang Jing, Chi Haibo, Huang Pujiang
Coal Geology & Exploration
Coal and gas outburst is a complex geo-dynamic disaster induced by a coal seam uncovered by crossdrift, threatens the safety and efficient production of coal mines seriously. For this, Hongshan coal mine was selected as engineering background to simulate mechanical response characteristics of surrounding rock during uncovering No.12 coal seam in a gas bursting hazardous zone with FLAC3D software. Then the outburst mechanism during uncovering a coal seam by a crossdrift was revealed, and comprehensive outburst prevention technology combining mine gas pre-drainage and improved metal skeleton was put forward. The results showed that the abutment pressure ahead of the …
Molecular Simulation Of The Influence Of Foam Fracturing Fluid Additives On Coalbed Methane Diffusion,
2019
State Key Lab of Oil and Gas Reservoir Geology and Exploitation Engineering, Southwest Petroleum University, Chengdu 610500, China
Molecular Simulation Of The Influence Of Foam Fracturing Fluid Additives On Coalbed Methane Diffusion, Yang Zhaozhong, Han Jinxuan, Zhang Jian, He Rui, Lu Yanjun, Li Xiaogang
Coal Geology & Exploration
Materials Studio(MS) software was used to establish a slit pore molecular model which considers the in-teractions among water-bearing coal, foam agent and foam stabilizer. Based on molecular diffusion theory, the diffusion ability of methane molecule respectively affected by four common foam agents and four foam stabilizers was calculated. Compared to original water-bearing coal, self-diffusion coefficient of coalbed methane(CBM) is reduced by 71.3%, 74.7%, 56.3%, 54.0% after adding foaming agents including sodium dodecyl sulfonate(SDS), sodium lauryl sulfate(SLS), sodium dodecyl benzene sulfonate(SDBS) and lycine respectively. Based on adding SDBS into water-bearing coal, the self-diffusion coefficient of CBM is further reduced by 63.2%, …
Reasons Of Low Yield And Stimulation Measures For Vertical Cbm Wells In High-Rank Coal,
2019
Shanxi CBM Branch Company, PetroChina Huabei Oilfield, Changzhi 046000, China
Reasons Of Low Yield And Stimulation Measures For Vertical Cbm Wells In High-Rank Coal, Jia Huimin, Hu Qiujia, Qi Kongjun, Liu Chunchun, Fan Bin, He Jun
Coal Geology & Exploration
The CBM production is usually low and development effect is poor in China, which are mainly due to the poor adaptability of the stimulation measures to the geological conditions. This article, based on the low-yield reasons for vertical CBM wells in Zhengzhuang block in southern Qinshui basin, puts forth corresponding stimulation measures, analyzes the mechanism and the geological adaptability, optimizes the parameters of specific stimulation measures and carries out pilot test. The research and practices show that in deeply buried area, fractures are difficult to form, and re-fracturing technology can make the fracture turn and increase the crack length, which …
Estimation Method And Application Of Free Gas Content In Coal,
2019
Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
Estimation Method And Application Of Free Gas Content In Coal, Jiang Wenping, Zhang Qun, Zhang Peihe, Dong Mintao, Tian Xinjuan, Ru Ting
Coal Geology & Exploration
In order to study the distribution characteristics of free gas content in coal reservoirs, based on the understanding that free gas mainly exists in coal pores, the estimation method of free gas content is optimized. Based on the test data of coalbed methane arameters of 42 groups of coals with different ranks from lignite to anthracite in typical coal-bearing areas of China, the free gas content of different coal samples were calculated by using the optimized method of free gas content estimation, and compared with the results of desorption gas content. The results show that the ratio of free gas …
Analysis On The Type Of Reservoir Pressure Drop And Drainage Control Of Coalbed Methane Well In The Southern Block Of Shizhuang,
2019
School of Energy and Resources, China University of Geoscience, Beijing 100083, China; Beijing Key Laboratory of Unconventional Natural Gas Geological Evaluation and Development Engineering, Beijing 100083, China; Shanxi key Laboratory of Resources, Environment and Disaster Monitoring, Jinzhong 030600, China
Analysis On The Type Of Reservoir Pressure Drop And Drainage Control Of Coalbed Methane Well In The Southern Block Of Shizhuang, Yi Yongxiang, Tang Shuheng, Zhang Songhang, Yan Xinlu, Wang Kaifeng, Dang Feng
Coal Geology & Exploration
In order to fully understand the reservoir pressure variation characteristics of coalbed methane wells in the southern block of Shizhuang and based on the analysis of reservoir geological parameters and the analysis of actual production data, the reservoir pressures of different types of production wells are analyzed. The specific analysis of the drainage control and reservoir sensitivity effects is also carried out based on the abnormal wells. The results showed that the reservoir lamination of coalbed methane wells in the southern block of Shizhuang can be divided into three types, namely type of rapid pressure drop, type of medium-term stability …
Development And Test Of Self-Adjusting Deflected Wellhead Sealing Device For Coalbed Methane Wells,
2019
Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
Development And Test Of Self-Adjusting Deflected Wellhead Sealing Device For Coalbed Methane Wells, Pang Tao
Coal Geology & Exploration
In order to solve the problem of fluid and gas leakage in coal seam gas well, a self-adjusting deflected wellhead sealing device suitable for coal seam gas wells is developed. The device consists of three parts:Smooth rod sealing box, self-adjusting deflected part and lower sub. The self-adjusting deflected part is a smart combination of universal joint and high pressure flexible rubber tube, which makes the sealing box and the polished rod always keep good concentricity. Practical application shows that this kind of polished rod sealing device has reliable sealing performance, simple structure and the prospect of popularization and application.
Experimental Study On Contact Angle And Pore Characteristics Of Unsaturated Loess,
2019
School of Civil Engineering, Chang'an University, Xi'an 710061, China
Experimental Study On Contact Angle And Pore Characteristics Of Unsaturated Loess, Jing Yanlin, Wang Hao, Tao Chunliang, Yang Lina, Liu Jianwei, Wen Xin
Coal Geology & Exploration
Contact angle and pore size are important factors affecting soil wettability, permeability and capillarity. In order to further understand the capillary characteristics and permeability of unsaturated loess, the contact angle test and mercury intrusion test of unsaturated loess were carried out. The relationship between pore size and contact angle was analyzed in details. Moreover, the variation of pore and contact angle with depth was discussed. It is found that the contact angle of loess in the dry state is higher than the contact angle of loess in the natural state; as the depth of the formation increases, the contact angle …
Influence Of Loading Rate On The Fracture Characteristics Of Large-Size Specimen,
2019
College of Geosciences and Surveying Engineering, China University of Mining and Technology(Beijing), Beijing 100083, China; State Key Laboratory of Mining Disaster Prevention and Control of Shandong University of Science and Technology, Qingdao 266590, China
Influence Of Loading Rate On The Fracture Characteristics Of Large-Size Specimen, Chen Juntao, Li Ming, Cheng Binbin, Yang Fan, Men Huili, Shao Zhujuan
Coal Geology & Exploration
According to the high mining speed of modern mines in China, the fracture characteristics of rock mass under different uniaxial loading rate was systematically analyzed. Based on the geological condition of deep rock mass in Jining area, the optimum mortar composed of 425 Portland cement, sand with particle size less than 2 mm, gypsum, water and high efficient water reducer was used, which had the mechanical properties similar to real rock mass was ascertained. Applying the triaxial rock test system of coupled stress-seepage and PCI-2 real-time monitoring system of AE, the fracture process of specimens of large size under biaxial …
A New Instability Criterion Of Double Strength Reduction Method For Slope,
2019
Geomatics and prospecting Engineering, Jilin Jianzhu University, Changchun 130118, China; School of Civil Engineering and Architecture, Northeast Electric Power University, Jilin 132012, China
A New Instability Criterion Of Double Strength Reduction Method For Slope, Fang Hongwei, Wu Jianxun, Hou Zhenkun
Coal Geology & Exploration
Based on the slip line field theory(SLFT), a new instability criterion of strength reduction method with double re-duction factors for homogeneous slopes was proposed. It is judged that the slope is in the limit equilibrium state when the slope contour under limit equilibrium state(abbreviated as the critical slope contour) calculated by the SLFT intersects with the slope line at the toe. The critical curve was constructed in the plane of the inverse of the double reduction factors, and the comprehensive safety factor was derived. The slope calculation results show that three relative position relationships between the initial point and the …
The Effect Of Viscoelasticity And Velocity Anisotropy On The Reflections Of A Thin Bed,
2019
Science&Technology Department, Sinopec, Beijing 100728, China
The Effect Of Viscoelasticity And Velocity Anisotropy On The Reflections Of A Thin Bed, Chen Benchi, Wang Chao, Chen Changxing, Shi Lei
Coal Geology & Exploration
The coal seam is a typical thin bed characterized by much lower elastic impedance than that of the surrounding rock. Coal seam has viscoelasticity and velocity anisotropy and its reflection amplitude changes with frequency. In order to analyze the effect of viscoelasticity and velocity anisotropy on seismic responses of a thin bed, this paper aims at a thin-bed model with strong impedance contrast and simulates seismic responses under three different assumptions, elastic and velocity isotropy, viscoelastic and velocity isotropy, and viscoelastic and velocity anisotropy, through numerical simulation method based on wave equations. Comparison of these seismic reflections shows that the …
