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Full-Text Articles in Physical Sciences and Mathematics

Challenges For The Ratification Of The Hong Kong Convention For The Safe And Environmentally Sound Recycling Of Ships, 2009 In Indonesia, Monica Ajeng Oktaviany Nov 2019

Challenges For The Ratification Of The Hong Kong Convention For The Safe And Environmentally Sound Recycling Of Ships, 2009 In Indonesia, Monica Ajeng Oktaviany

World Maritime University Dissertations

No abstract provided.


Developing Safe And Environmentally Sound Ship Recycling In Indonesia, . Irawati Nov 2019

Developing Safe And Environmentally Sound Ship Recycling In Indonesia, . Irawati

World Maritime University Dissertations

No abstract provided.


Wind Propulsion Optimisation And Its Integration With Solar Power, Mphatso Nsanjama Nyanya, Huy Ba Vu Nov 2019

Wind Propulsion Optimisation And Its Integration With Solar Power, Mphatso Nsanjama Nyanya, Huy Ba Vu

World Maritime University Dissertations

No abstract provided.


An Assessment Of Development Opportunities Of Ship Recycling Facilities Based On The Shipbuilding Yards' Infrastructures In Vietnam, The Quyen Pham Nov 2019

An Assessment Of Development Opportunities Of Ship Recycling Facilities Based On The Shipbuilding Yards' Infrastructures In Vietnam, The Quyen Pham

World Maritime University Dissertations

No abstract provided.


Functional Dissection Of The Chickpea (Cicer Arietinum L.) Stay-Green Phenotype Associated With Molecular Variation At An Ortholog Of Mendel’S I Gene For Cotyledon Color: Implications For Crop Production And Carotenoid Biofortification, Kaliamoorthy Sivasakthi, Edward Marques, Ng’Andwe Kalungwana, Noelia Carrasquilla-Garcia, Peter L. Chang, Emily M. Bergmann, Erika Bueno, Matilde Cordeiro, Syed Gul A.S. Sani, Sripada M. Udupa, Irshad A. Rather, Reyazul Rouf Mir, Vincent Vadez, George J. Vandemark, Pooran M. Gaur, Douglas R. Cook, Christine Boesch, Eric J.B. Von Wettberg, Jana Kholova, R. Varma Penmetsa Nov 2019

Functional Dissection Of The Chickpea (Cicer Arietinum L.) Stay-Green Phenotype Associated With Molecular Variation At An Ortholog Of Mendel’S I Gene For Cotyledon Color: Implications For Crop Production And Carotenoid Biofortification, Kaliamoorthy Sivasakthi, Edward Marques, Ng’Andwe Kalungwana, Noelia Carrasquilla-Garcia, Peter L. Chang, Emily M. Bergmann, Erika Bueno, Matilde Cordeiro, Syed Gul A.S. Sani, Sripada M. Udupa, Irshad A. Rather, Reyazul Rouf Mir, Vincent Vadez, George J. Vandemark, Pooran M. Gaur, Douglas R. Cook, Christine Boesch, Eric J.B. Von Wettberg, Jana Kholova, R. Varma Penmetsa

College of Agriculture and Life Sciences Faculty Publications

“Stay-green” crop phenotypes have been shown to impact drought tolerance and nutritional content of several crops. We aimed to genetically describe and functionally dissect the particular stay-green phenomenon found in chickpeas with a green cotyledon color of mature dry seed and investigate its potential use for improvement of chickpea environmental adaptations and nutritional value. We examined 40 stay-green accessions and a set of 29 BC2F4-5 stay-green introgression lines using a stay-green donor parent ICC 16340 and two Indian elite cultivars (KAK2, JGK1) as recurrent parents. Genetic studies of segregating populations indicated that the green cotyledon trait is controlled by a …


Designing A Global Mechanism For Intergovernmental Biodiversity Financing, Nils Droste, Joshua Farley, Irene Ring, Peter H. May, Taylor H. Ricketts Nov 2019

Designing A Global Mechanism For Intergovernmental Biodiversity Financing, Nils Droste, Joshua Farley, Irene Ring, Peter H. May, Taylor H. Ricketts

Rubenstein School of Environment and Natural Resources Faculty Publications

The Convention on Biological Diversity and the Nagoya Protocol display a broad international consensus for biodiversity conservation and equitable benefit sharing. Yet, the Aichi biodiversity targets show a lack of progress and thus indicate a need for additional action such as enhanced and better targeted financial resource mobilization. To date, no global financial burden-sharing instrument has been proposed. Developing a global-scale financial mechanism to support biodiversity conservation through intergovernmental transfers, we simulate three allocation designs: ecocentric, socioecological, and anthropocentric. We analyze the corresponding incentives needed to reach the Aichi target of terrestrial protected area coverage by 2020. Here we show …


Genotype-Specific Effects Of Ericoid Mycorrhizae On Floral Traits And Reproduction In Vaccinium Corymbosum, Alison K. Brody, Benjamin Waterman, Taylor H. Ricketts, Allyson L. Degrassi, Jonathan B. González, Jeanne M. Harris, Leif L. Richardson Nov 2019

Genotype-Specific Effects Of Ericoid Mycorrhizae On Floral Traits And Reproduction In Vaccinium Corymbosum, Alison K. Brody, Benjamin Waterman, Taylor H. Ricketts, Allyson L. Degrassi, Jonathan B. González, Jeanne M. Harris, Leif L. Richardson

Rubenstein School of Environment and Natural Resources Faculty Publications

American Journal of Botany is published by Wiley Periodicals, Inc. on behalf of the Botanical Society of America. Premise: Most plants interact with mycorrhizal fungi and animal pollinators simultaneously. Yet, whether mycorrhizae affect traits important to pollination remains poorly understood and may depend on the match between host and fungal genotypes. Here, we examined how ericoid mycorrhizal fungi affected flowering phenology, floral traits, and reproductive success, among eight genotypes of highbush blueberry, Vaccinium corymbosum (Ericaceae). We asked three overarching questions: (1) Do genotypes differ in response to inoculation? (2) How does inoculation affect floral and flowering traits? (3) Are inoculated …


Consolidated Climate Markets Mechanism Analysis—Case Studies Of China, Japan, And Taiwan, Jules Chuang, Hsing-Lung Lien, Akemi Kokubo Roche, Pei-Hsuan Liao, Walter Den Nov 2019

Consolidated Climate Markets Mechanism Analysis—Case Studies Of China, Japan, And Taiwan, Jules Chuang, Hsing-Lung Lien, Akemi Kokubo Roche, Pei-Hsuan Liao, Walter Den

Water Resources Science and Technology Faculty Publications

The post-Kyoto Protocol era has seen a transition to focus on the development of a renewable energy (RE) market as a primary instrument to reduce greenhouse gas (GHG) emissions worldwide. This paper analyses the development of GHG reduction and RE market in China, Japan, and Taiwan that are geographically proximate but socioeconomically diverse, and each plays a different but significant role in the world’s economy. By deploying a consolidated model incorporating the key components of market drivers underlying the goal of achieving GHG reduction, we threaded through the policy- and market-instruments implemented for each of the case studies over the …


Organic Agriculture Teaching And Learning In 2025: Transforming The Future Learning Landscape, Randa Jabbour, Charles A. Francis, Mary Barbercheck, Katharina S. Ullman Nov 2019

Organic Agriculture Teaching And Learning In 2025: Transforming The Future Learning Landscape, Randa Jabbour, Charles A. Francis, Mary Barbercheck, Katharina S. Ullman

Department of Agronomy and Horticulture: Faculty Publications

University instructors are compelled to anticipate future changes in farming and food systems that will impact their students. Sixteen educators met in 2018 to envision the future of organic agriculture courses needed by 2025. Likely future global issues include food access, especially for people of limited economic means; climate change; and fossil fuel costs. Changes that will impact education are increasing demand for quality food, more organic production, and globalization of food systems due to consolidation. Probable course content changes are increasing focus on whole farm systems; designing for resilience in changing physical, economic, environmental, and political climates; and increasing …


Electronic Field Trips For Science Engagement: The Streaming Science Model, Jamie Loizzo, Mary J. Harner, Deborah J. Weitzenkamp, Kevin Kent Nov 2019

Electronic Field Trips For Science Engagement: The Streaming Science Model, Jamie Loizzo, Mary J. Harner, Deborah J. Weitzenkamp, Kevin Kent

Journal of Applied Communications

While institutions of higher education work to engage PK-12 youth in STEM (science, technology, engineering, and mathematics) concepts and careers via in-person programming, PK-12 teachers and students face many logistical and access constraints for physically traveling to sites off of school grounds during the school day. Throughout the years, electronic field trips (EFTs) have offered a digital way for schools to engage in meaningful ways with museums, parks, laboratories, and field research sites. In order for EFTs to be effective, they should be cost effective and created collaboratively with teachers, students, subject matter experts, and instructional design and communication professionals. …


The Paradox Of Urban Greening: Does It Harm The Very People Who Need It The Most?, Juliana Maantay Oct 2019

The Paradox Of Urban Greening: Does It Harm The Very People Who Need It The Most?, Juliana Maantay

Sustainability Seminar Series

Urban greening and sustainability approaches are well accepted methods for improving the urban environment and combating the climate crisis. Cleaning up potentially contaminated lands and bringing them back into constructive public use is one of the benefits of greening. However, greening efforts may have unintended consequences, resulting in adverse social and economic impacts to the existing residents, who are often the most vulnerable urban populations. Spatial analyses of case study examples show that greening can spur “green gentrification.” Measures can be taken to integrate social equity objectives into urban sustainability planning, to mitigate gentrification, and to improve equitable distribution of …


Fractal Theory-Based Investigation Of The Optimal Interval Of Minimum Pore Radius Of Sandstone, Xu Lulu, Dong Shuning, Dai Zhenxue, Xu Bin, Yin Shangxian, Zhou Yan, Chen Junjun Oct 2019

Fractal Theory-Based Investigation Of The Optimal Interval Of Minimum Pore Radius Of Sandstone, Xu Lulu, Dong Shuning, Dai Zhenxue, Xu Bin, Yin Shangxian, Zhou Yan, Chen Junjun

Coal Geology & Exploration

Permeability is a main parameter for evaluation of water conductivity of porous media, and it is a macroscopic feature of micro-pore structure of water-conducting media. To obtain the geometry parameters of microscopic pores, we performed scanning electron microscopy(SEM) on sandstone samples. The image processing techniques were also applied in calculation of different statistical parameters(e.g., fractal dimensions) and geometrical parameters. Then, fractal theory was introduced to investigate the influence of micro pore structure on permeability. At the same time, the minimum pore radius rmin interval acting on the seepage was obtained by the measured permeability values. This interval can be …


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 Oct 2019

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 …


Test Of The Influence Of Dynamic Water Grouting Diffusion Radius Of Fractures In Rock, Gu Shuancheng, Sun Guanlin, Su Peili, Li Jinhua Oct 2019

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 …


Design And Application Of Multi-Section Bundled Bag Wire-Line Coring Drilling Tools, Han Yi, Zhang Shaohe, Bai Rui, Sun Pinghe, Shu Biao, Cao Han, Zhang Xinxin Oct 2019

Design And Application Of Multi-Section Bundled Bag Wire-Line Coring Drilling Tools, Han Yi, Zhang Shaohe, Bai Rui, Sun Pinghe, Shu Biao, Cao Han, Zhang Xinxin

Coal Geology & Exploration

Because the existing conventional wire-line coring drilling tool lacks the water-proof and core-protecting device, the broken core is easily eroded when the core is drilled in a complicated layer such as loose, weak, broken layers and the core is easy to fall off during the lifting process, so that the coring rate and core quality are not up to the design requirements, and even core can not be taken to. In response to the above problems, a bag-type wire-line coring drilling tool was designed. The drill adds a multi-section bundled bag assembly structure to the conventional wire-line coring drilling tool …


Experimental Study Of Three-Component Down-Hole Tem For Detecting Water-Filled Goaf, Yao Weihua, Wang Peng, Li Mingxing, Su Chao, Cheng Siyuan Oct 2019

Experimental Study Of Three-Component Down-Hole Tem For Detecting Water-Filled Goaf, Yao Weihua, Wang Peng, Li Mingxing, Su Chao, Cheng Siyuan

Coal Geology & Exploration

The borehole geophysical prospecting method is a research hotspot in recent years. Considering that the down-hole transient electromagnetic method used in metal mines has the characteristics of long radial detection distance and less susceptible to surface electromagnetic interference, it is applied to the exploration of water-filled goaf in coal mines. Three-dimensional finite-difference time-domain(FDTD) algorithm is used to simulate the total field response and abnormal response of the goaf model with different orientations of boreholes. The total field three-component could reflect the water-filled goaf obviously, and the abnormal field three-component shape combination can distinguish the azimuth of the abnormal body. Based …


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 Oct 2019

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 …


Table Of Contents, The Editors Oct 2019

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.


Trilinear Chart Classification Method Of Mine Water Hazard Type Based On Factors Of Water Recharge, Hu Weiyue, Zhao Chunhu Oct 2019

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 …


Evaluation Technology For Key Monitoring Area Of Early Warning Of Water Inrush From The Floor Of Working Face In Coal Mine, Liu Demin, Yin Shangxian, Lian Huiqing Oct 2019

Evaluation Technology For Key Monitoring Area Of Early Warning Of Water Inrush From The Floor Of Working Face In Coal Mine, Liu Demin, Yin Shangxian, Lian Huiqing

Coal Geology & Exploration

Accurately delineating the key monitoring areas for water inrush warning of the floor of working face in coal mine and realizing the spatial matching of the monitoring position of the early warning system and the location of potential water inrush points are one of the urgent problems to be solved in the warning of water inrush from the floor of working face in coal mine. In order to study the evaluation technology for key monitoring area of water inrush warning of the floor of working face in coal mine, hydrogeological analysis, GIS spatial analysis and ANN prediction were used to …


Stability Of Cement-Based Grouting Slurry And Test Of Its Bleeding Law, Xu Bin, Dong Shuning, Xu Lulu, Zhou Yan, Chen Junjun, Dai Zhenxue, Wang Hao Oct 2019

Stability Of Cement-Based Grouting Slurry And Test Of Its Bleeding Law, Xu Bin, Dong Shuning, Xu Lulu, Zhou Yan, Chen Junjun, Dai Zhenxue, Wang Hao

Coal Geology & Exploration

To better understand the stability performance and bleeding property of cement-based grouting slurry, a new test device was improved to get the separated-water thickness value of slurry samples at every time, and these samples were made and sorted according to the certain proportion of the water-solid ratio(0.6:1 to 3:1), fly ash content(0-90%) and sodium silicate content(0-12%). The growth theory for separated-water thickness was introduced, and the growth curves for all formulations were plotted. The slurry stability measurement method was classified, and the equivalence relation between the direct measurement method of slurry stability and the indirect measurement method was verified. The …


Analytical Solution For Surrounding Rock Of Circular Roadway Based On Generalized Smp Criterion Considering Seepage And Dilatancy, Pan Jiliang, Ren Fenhua Oct 2019

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 …


Spatial Distribution And Formation Of Groundwater Hydrochemistry In Huainan Coalfield, Wang Zitao, Liu Qimeng, Liu Yu Oct 2019

Spatial Distribution And Formation Of Groundwater Hydrochemistry In Huainan Coalfield, Wang Zitao, Liu Qimeng, Liu Yu

Coal Geology & Exploration

In order to study the spatial distribution of groundwater in Huainan coalfield and the intensity of various hydrochemical actions, the coalfied is divided into the northern district with thicker loose beds and the southern district with thinner loose beds. Hydrochemical test data of main water-inrushing aquifers in 16 mines in these two areas were collected and statistically analyzed, ion combination method and Gibbs diagram were used to study the groundwater hydrochemical characteristics of each aquifer in north and south areas. The results indicate that TDS of aquifer is positively correlated with the burial thickness of unconsolidated formation. With the increase …


Fractal Characteristics Of Pores And Microfractures Of Coals With Different Structure And Their Effect On Permeability, Ye Zhenni, Hou Enke, Duan Zhonghui, Wen Qiang, Huang Meitao, He Dan Oct 2019

Fractal Characteristics Of Pores And Microfractures Of Coals With Different Structure And Their Effect On Permeability, Ye Zhenni, Hou Enke, Duan Zhonghui, Wen Qiang, Huang Meitao, He Dan

Coal Geology & Exploration

The characteristics of pores and fractures in coal are the basis to study permeability. In this study, the micro-pores and fractures of coal samples with different structure taken from Guojiahe coal mine were analyzed using mercury injection experiment and scanning electron microscope. The micro-pores and fractures of intact coal and cataclastic coal samples were quantitatively analyzed by using Menger sponge and box-counting dimension. The comprehensive fractal dimension was calculated by pore volume weights. Based on fractal theory, the relationship between fractal dimension of coal samples and coal permeability have been discussed. The results show that brittle deformation adds complexity of …


The Discovery And Geological Significance Of Coal-Formed Graphite In Chongyi Coal Mine In Jiangxi Province, Li Yang, Wang Lu, Cao Daiyong, Du Xin, Zhao Meng, Liu Liming, Wei Yingchun Oct 2019

The Discovery And Geological Significance Of Coal-Formed Graphite In Chongyi Coal Mine In Jiangxi Province, Li Yang, Wang Lu, Cao Daiyong, Du Xin, Zhao Meng, Liu Liming, Wei Yingchun

Coal Geology & Exploration

In order to study the characteristics of coal-formed graphite in Chongyi mine, Jiangxi Province, the coal in Laoshan Section of Upper Permian Longtan Formation in Chongyi mining area was tested and analyzed by means of optical microscope, X-ray diffraction(XRD), Raman spectroscopy and HRTED. The test results showed that the graphitization maceral could be observed under the optical microscope. The XRD diffraction pattern showed a graphite diffraction peak of d002, and the Raman spectrum showed a characteristic peak of graphite(G peak) with sharp peak shape. Multilayer ordered structure of carbon layer was observed by high resolution transmission electron microscope, …


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 Oct 2019

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, Yang Zhaozhong, Han Jinxuan, Zhang Jian, He Rui, Lu Yanjun, Li Xiaogang Oct 2019

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%, …


Estimation Method And Application Of Free Gas Content In Coal, Jiang Wenping, Zhang Qun, Zhang Peihe, Dong Mintao, Tian Xinjuan, Ru Ting Oct 2019

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, Yi Yongxiang, Tang Shuheng, Zhang Songhang, Yan Xinlu, Wang Kaifeng, Dang Feng Oct 2019

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, Pang Tao Oct 2019

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.