Engineering Commons^™

Numerical Simulation On Evolution Law Of Overburden Fractures And Surface Cracks In Crossing Ditch Mining Of Shallow Coal Seam, Wei Jiangbo, Wang Shuangming, Song Shijie, Sun Qiang

Coal Geology & Exploration

Crossing ditch mining of shallow coal seam is common in northern Shaanxi mining area, which seriously threatens the safe production and the sound ecological development. The mining-induced overburden fractures and surface cracks are developed as a result of the extension and expansion of microcracks in rock mass. In order to more systematically study the evolution law of overburden microcracks in crossing ditch mining of shallow coal seam, a numerical model of particle flow in coal mining was established with the Particle Flow Code (PFC) numerical simulation platform according to the field ditch profile and borehole data under the background of …

Experimental Study On Stress Relaxation Characteristics Of Soft Dredger Fill Under Uu Triaxial Shear, Yang Aiwu, Yang Shaopeng, Qi Jiejie

Coal Geology & Exploration

Stress relaxation often occurs in the saturated soft clay with poor water permeability under the actual working condition at fast construction speed (fast loading rate), which brings huge hidden dangers to the safe operation of engineering practice. Herein, the unconsolidated undrained triaxial shear test was performed based on the soft dredger fill in Tianjin Binhai using the WF stress path triaxial instrument, and the influence law of such factors as the different initial strain, confining pressure, shear rate, sampling depth and structural properties of the soft dredger fill on its stress relaxation characteristics was analyzed accordingly. According to the test …

Spatial Variation Characteristics Of Soil Heavy Metal Speciation And Bioavailability In Coal Gangue Accumulation Area—Taking Fengfeng Mining Area As An Example, Sun Tao, Song Shijie, Chang Qing, Wang Chenchen, Zhang Yanjie, Peng Ruisi, Wang Yi

Coal Geology & Exploration

The surface accumulation of coal gangue is a typical form of ecological environment destruction in the eastern coal mining area of China, and the prevention and control of heavy metal pollution in the soil in the accumulation area has become a hot spot in the current research. Taking the shallow soil (with a vertical depth of 40 cm and below) around a coal gangue mountain (within a radius of 300 m) in use in the Fengfeng mining area of Hebei as the research object, the active state, iron manganese oxidation state, organic state and residue state of four kinds of …

Effect Of Initial Adhesion On Shear Strength And Deformation Characteristics Of Interfaces In Heterogeneous Soils, Zhu Yanbo, Yang Fanfan, Miao Shuaisheng, Li Futong, Zhang Yuxuan

Coal Geology & Exploration

In the Loess Plateau of China, the interface between the Loess and Hipparion Red Clay is widely distributed. The initial adhesion between this interfaces plays an important role in its shear strength. To investigate the effect of initial adhesion on shear strength and deformation characteristics of the interfaces, we firstly performed a series of direct shear experiments. Then, we discussed the effects of initial adhesion on failure mode, shear deformation and shear strength of interfaces. The results indicate that the failure modes of interfaces with initial adhesion and interfaces without initial adhesion are different. The initial adhesion improves the sliding …

Research And Application Progress Of Energy Underground Structures, Wen Jiwei, Hou Junlong, Liu Xinghong, Zeng Xian’En, Xiang Tian

Coal Geology & Exploration

Energy geostructure refers to a type of structure equipped with heat exchange pipe in the building foundation element and the underground structure, which has the functions of load bearing and heat exchange. It not only effectively saves the valuable and irreversible underground space resources, but also makes full use of the non-carbon based continuous, stable, safe and clean geothermal energy resources, thus having more advantages than the traditional Ground Source Heat Pump (GSHP). Herein, the concept, advantages, research and application progress of energy geostructure at home and abroad were systematically summarized. Moreover, the current situation of four common energy geostructures, …

Numerical Simulation Of The Influence Of Karst Structure On Heat Transfer Efficiency Of Buried Pipeline Group, Mu Xuan, Pei Peng, Zhou Xin, Tu Hongsheng

Coal Geology & Exploration

The buried pipeline is the part where the rock mass heat pump system performs direct heat transfer with the ground. The water-bearing structure in the karst area is complex and diverse, which has a significant impact on the heat transfer and storage of the buried pipeline group. Herein, the heat transfer process of a group of 27 vertical buried pipelines in four geological structure types was simulated, including the non-karst structure, fractured karst structure, karst conduit structure and mixed karst structure. Meanwhile, comparison was made for the change of parameters, such as the temperature field in the rock mass, the …

Numerical Simulation On Azimuth Gamma Ray Detection Of Coal And Rock Interface, Chen Gang, Chen Long, Li Quanxin, Liu Zhiyi

Coal Geology & Exploration

In order to meet the requirements of geosteering drilling with LWD azimuth gamma, the response value of gamma ray intensity under different surrounding rock thicknesses and absorption coefficients was studied by numerical simulation. Meanwhile, the variation of special and physical characteristics reflected by API value measured by gamma detector under the radioactive formation conditions was simulated and analyzed. On this basis, the geological model of the three layers of coal, mudstone and limestone of 8-sectors azimuth gamma ray drilling was established to simulate the identification process of roof and floor of coal bed drilled. The simulation results show that the …

Time-To-Depth Conversion Accuracy Analysis And Improvement Method For Inclined Coal Bed, Wang Huifeng, Fu Chao, Li Guo, Chen Tongjun

Coal Geology & Exploration

The average-velocity method is the most commonly-used time-to-depth conversion technology for the seismic survey of coalbed. But for the steeply-inclined coalbed, the average velocity changes rapidly laterally, and the interpretation accuracy varies greatly, so that the intelligent coal mining could not be assured effectively. Herein, the accuracy of various average-velocity-interpolation methods was discussed by analyzing a steeply-inclined coalbed model and a practical 3D seismic mining area and appropriate improvement methods were proposed accordingly. The calculation results of a forward model show that the bottom elevation accuracy of coalbed is greatly affected by the locations of interpolation points in the case …

Air-Driven Directional Drilling Technology And Equipment In Soft Coal Seam Of Huainan Mining Area, Tian Hongliang, Chen Jian, Zhang Jie, Cheng Heyu, Dong Ruigang, Du Limeng, Liu Degui, Guan Qiangsheng

Coal Geology & Exploration

Aiming at Huainan mining area using bedding directional drilling to eliminate gas outburst in strip coal seams of working face and adjacent roadways, we put forward a technical idea of using pneumatic long directional drilling hole to eliminate gas outburst by one hole. On the basis of the previous pneumatic screw directional drilling technology test, we developed a narrow-body full-section remote directional drilling rig with a width of only 1.1 m, the spindle angle can be stepless adjusted from −90° to 90°, and maximum remote distance of 50 m. The ø73/82 mm screw pneumatic screw drill was optimized, with maximum …

Influencing Factors Of Increasing The Signal Strength Of The Em-Mwd By Applying Insulation Coating Outside The Casing, Shao Chun, Hu Chuang, Xu Lin, Chen Minghua, Long Xiaoping

Coal Geology & Exploration

Applying insulation coating outside the casing can reduce the attenuation of Electromagnetic measurement-while-drilling (EM-MWD) signals in low resistivity formations and increase the transmission depth of EM-MWD signals. For the purpose of obtaining the resistivity range of the formation applicable to the insulation coating and the influence of the coating characteristics on the received signal strength, a simulation model is established based on the finite element method, and simulation experiments are carried out on the application effect of the insulation coating applied to the casings of different resistivity formations and the influence regularity of the coating resistivity, thickness and length on …

Redevelopment Strategy Of Closed Coal Mine Industrial Plaza: A Case Study Of Fenghuangshan Mine In Jincheng, China, Wang Jingxiang, Chang Jiang, Deng Yuanyuan, Lin Yan, Wu Haoran

Coal Geology & Exploration

With the effective implementation of China’s policy on cutting the overcapacity of coal, a number of mines with exhausted resources and backward production capacity have been shut down and abandoned. Thus, the traditional independent industrial and mining areas become silent, and the industrial plazas serving coal production and workers’ lives are faced with the problems such as function loss and idle land. Therefore, excavating the value of the closed coal mine industrial plazas and giving it new functions is the key to revitalize the existing resources and stimulate the vitality of independent industrial and mining areas. Herein, research was conducted …

Population Health Metrics During The Early Stages Of The Covid-19 Pandemic: Correlative Pilot Study, Marie A. Severson, David A. Cassada, Victor C. Huber, Daniel D. Snow, Lisa M. Mcfadden

Nebraska Water Center: Faculty Publications

Background: COVID-19 has caused nearly 1 million deaths in the United States, not to mention job losses, business and school closures, stay-at-home orders, and mask mandates. Many people have suffered increased anxiety and depression since the pandemic began. Not only have mental health symptoms become more prevalent, but alcohol consumption has also increased during this time. Helplines offer important insight into both physical and mental wellness of a population by offering immediate, anonymous, cheap, and accessible resources for health and substance use disorders (SUD) that was unobstructed by many of the mandates of the pandemic. Further, the pandemic also …

Creating Sustainable Biofuels Using Essential Oil Distillery Leaf Waste Near Vohimana Reserve, Ashley Cohen

Independent Study Project (ISP) Collection

Like most of Madagasacar’s population, people around Vohimana Reserve rely on traditional fuels like firewood and charcoal for cooking and heating. As a result, the region is facing deforestation, which poses a threat to biodiversity and the livelihoods of local populations. A local essential oil distillery was created by the NGO L’Homme et L’Environnement as a sustainable income generator to combat deforestation and protect biodiversity. The distillery produces leaf biomass that can be mixed with binding agent(s) and transformed into biofuel as a sustainable alternative to traditional fuels. 14 biofuels were created by combining distillery leaf biomass and various percent …

Big Lagoon Sea Level Rise, Kyra Cohen, Malia Seeley, Dustin Helliwell, Albert Wolff

Student Projects

Cal Poly Humboldt Environmental Resources Engineering Senior Capstone.

The California Department of Transportation (Caltrans) is highly concerned sea level rise (SLR), due to climate change and the potential negative impacts on the California transportation system. SLR is especially important for routes constructed at low elevations and those immediately adjacent to the coast where SLR is one of the largest threats to the transportation system along the coast. Rising sea levels are expected to disrupt the daily lives of Californians, specifically the coastal economies, which increases the risk to public safety and contributes to the decline of ecosystems that are vital …

Sea Level Rise Analysis: High-Importance Access Road Protection, Max Alvin, Taylor Goodwyn, Karly Johnson, Pedro Valverde

Student Projects

Cal Poly Humboldt Environmental Resources Engineering Senior Capstone.

This report provides an analysis of design alternatives and ultimately a preferred design to ensure the longevity of Highway 101 near Orick, CA which is under threat of sea level rise (SLR). Highway 101 is the main transportation corridor for communities stretching from Arcata to Crescent City, California. Caltrans provided an area of interest along Highway 101 just southwest of Orick, between mile markers 119.58 and 119.92. The project area of interest is illustrated below in Figure ES-1. This stretch of Highway 101 borders low lying pastures and Redwood Creek's historic estuary. …

Lithofacies And Sedimentary Environment Evolution Of The Shan2 3 Sub-Member Transitional Shale Of The Shanxi Formation In The Daning-Jixian Area, Eastern Ordos Basin, Sun Yue, Jiang Yuqiang, Xiong Xianyue, Li Xingtao, Li Shuxin, Qiu Zhen, Sun Xiongwei

Coal Geology & Exploration

The Shan₂ ³ Sub-member transitional facies shale of the Permian Shanxi Formation in the eastern margin of the Ordos Basin is a crucial target for future unconventional oil and gas exploration. Based on field outcrop observation, core description and thin-section identification, combined with X-ray diffraction, trace elements test and other analyses, four types of shale lithofacies were identified, including siliceous, siliceous-argillaceous, calcareous-siliceous (or siliceous-calcareous) and argillaceous lithofacies. The petrological characteristics and geochemical indicators show that the depositional environment of the Shan₂ ³ Sub-member inherited the epicontinental sea pattern with relatively gentle topography of the late Taiyuan Epoch. The …

Stable-Production Period Prediction Method And Application In High-Rank Coalbed Methane Wells：A Case Study Of Fanzhuang-Zhengzhuang Block In Southern Qinshui Basin, Hu Qiujia, Jia Huimin, Zhang Cong, Fan Bin, Mao Chonghao, Zhang Qing

Coal Geology & Exploration

The prediction of stable-production period of Coalbed Methane (CBM) wells is of great significance to the prediction of reasonable stable gas rate and optimization of drainage strategy. Based on mass production data of different well types in Fanzhuang-Zhengzhuang Block, southern Qinshui Basin, the basic concepts of stable-production stage and period of CBM wells are clarified, and the empirical formula for the prediction of stable-production period is proposed and its influencing factors are analyzed. The results show that the CBM well keeps stable production by continuously reducing the bottom-hole-flowing pressure JHH, and the stable-production period is the time required for the …

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

Stress Sensitivity Characteristics And Control Mechanism Of Different Coal Rank Reservoirs, Sun Fenjin, Yang Jiaosheng, Wang Meizhu, Sun Bin, Zhang Jidong, Zhao Yang, Deng Ze

Coal Geology & Exploration

The stress sensitivity of coal reservoir reduces the permeability, which in turn affects the productivity of coalbed methane (CBM)wells. So how to reduce this effect from stress sensitivity deserves further study in the CBM wells drainage process. To clarify the stress sensitivity characteristic and differences of different rank coal reservoirs, coal samples collected respectively from Fanzhuang block (high rank coal), Baode block (medium rank coal) and Erlian Basin (low rank lignite) were employed in this study. The stress sensitivity experiments of different rank coal samples were systematically carried out during loading and unloading process. Meanwhile, stress sensitivity mechanism was analyzed. …

Optimum Selection Of Favorable Areas For Multi-Layer Cbm Mining And Reservoir Characterstics In North Yunnan And Guizhou Exploration Area, Sun Bin, Tian Wenguang, Yang Zhaobiao, Yang Minfang, Li Cunlei

Coal Geology & Exploration

Due to the abundance of coal-bearing synclines, multiple seams and high gas content, the exploration area in North Yunnan and Guizhou Provinces is an important expansion block in the periphery of Junlian County. Based on a large number of coalfield holes and test wells, the geological conditions of CBM are analyzed, and the optimization and evaluation method of multi-layer favorable area is established, i.e. multi-level fuzzy mathematics plus key indicators. Firstly, the evaluation model is constructed based on hierarchical optimization, and the key indicators are determined as co-mining coefficient, coal structure and gas content. The co-mining coefficient is composed of …

Damage Mechanism Of Cbm Reservoirs And Double-Layered Screen Pipes In The Horizontal Well Completion, Xian Bao'an, Zhang Long, Ha Erheng Tu’Ersong, Yu Peng, Wang Kai, Zhang Yafei, Zhang Yang, Wang Sanshuai, Li Zongyuan

Coal Geology & Exploration

Coal reservoirs have the characteristics of high adsorption, low permeability, easy compression and easy breakage. At the drilling and completing stage of horizontal coalbed methane wells, coal reservoir damage often occurs and leads to a significant reduction in coal seam permeability, thereby resulting in single well production. Through experimental analysis, the solid phase particles in drilling and completion fluids for horizontal well and the solid phase components induced by fluid flow are found to block the micro-fractures in the coal reservoir, and the damage mechanism for coal reservoir is elucidated to the drilling and completion reservoir of the horizontal well …

Construction Concept Of Integrated Geological Engineering Platform For Coalbed Methane, Li Guihong, Zhao Peipei, Wu Xinbo

Coal Geology & Exploration

The production of coalbed methane (CBM) wells in China is generally low, and the CBM geological research is seriously divorced from the engineering, so it is urgent to introduce the idea of geological engineering integration, which is helpful to form a scientific engineering decision. In this paper, the idea of constructing a CBM geological engineering integration platform is proposed, and its business framework and function framework are built. Various professional software tools are integrated, such as Petrel for geological modeling, compass for drilling and completion design, MFrac for fracturing design, and CBM-SIM for reservoir numerical simulation. An integrated shared database …

Geosteering Technology And Application In Horizontal Wells For Coal Measure Tight Gas Reservoirs In The Areas Of Low Exploration Degree：Taking Dj-P37 Bore Field As An Example, Zhang Wen, Zhang Lei, Huang Li, Li Xiaogang, Shi Shi, Sun Xuedong, Zhao Longmei, Dai Ruirui, Tong Jiangnan

Coal Geology & Exploration

In the 2D seismic area, the reservoir with a low well control degree, frontal sedimentary of the meandering river's delta and other complex lithology reservoirs, the drilling ratio of reservoirs is low when horizontal wells are implemented. The application of the geosteering technology combining the iterative updating of 3D geologic models and geologic-engineering integration has been gradually extensive. Multiple tight sandstone reservoirs, such as the Beichagou sandstone in the Shan₂ ³ Submember of the Shanxi Formation, develop in the Neopaleozoic coal measure at the southeastern margin of the Ordos Basin. Among them, the DJ-P37 bore field of the Daning–Jixian …

Coal Measures Superimposed Gas Reservoir And Its Exploration And Development Technology Modes, Sang Shuxun, Zheng Sijian, Yi Tongsheng, Zhao Fuping, Han Sijie, Jia Jinlong, Zhou Xiaozhi

Coal Geology & Exploration

Coal measures superimposed gas reservoir is a key reservoir type of coal-measure gas in coal bearing formation. The discovery, exploration and development practice of coal measures superimposed gas reservoirs in China have opened up a new chapter for the coal-measure gas exploration. In this study, the concept, main types, development characteristics and occurrence distribution of coal measures superimposed gas reservoir are proposed and expounded. The formation prerequisite, accumulation process and reservoir forming mechanism of coal measure superimposed gas reservoir are analyzed. Specifically, the geological suitability exploration and development technology modes of two typical coal measures superimposed gas reservoirs are emphatically …

Typical Coalbed Methane (Cbm) Enrichment And Production Modes Under The Control Of Regional Structure And Evolution, Ju Yiwen, Qiao Peng, Wei Mingming, Li Xin, Xu Fengyin, Feng Guorui, Li Yong, Wu Caifang, Cao Yunxing, Li Guofu, Han Yuming, Li Zhen, Lu Zhigang, Jiang Lei

Coal Geology & Exploration

Coalbed methane (CBM) exploration and development is of great significance to optimize China’s energy structure and cope with coal mine disasters and ecological environment problems. In this paper, combined with regional structure and evolution and CBM geological conditions, the enrichment and recovery modes of CBM are innovatively divided into four categories: simple structural fracture system, fold system (shallower synclinal shaft, fold limb, secondary structural high position), thrust system (fault-thrust-fold belt, high-steep thrust structure) and structural superposition system. Among them, simple structural fracture system mode is often encountered in the areas with relatively stable structure, where the CBM is mainly derived …

Application And Improvement Directions Of Rodless Drainage Technology In Coalbed Methane Wells: A Case Study From East Margin Of Ordos Basin, Ma Wentao, Liu Yinhua, Wu Jianjun, Wang Yubin, Wang Chengwang, Xu Wanyong

Coal Geology & Exploration

The eastern margin of Ordos Basin has a huge amount of coalbed methane resources, and has become one of the main coalbed methane producing areas in China. Since the development of the block, hydraulic rodless pump, hydraulic jet pump, electric submersible pump and diaphragm pump drainage and production process tests have been carried out for highly deviated wells and horizontal wells in medium shallow coal seam. During production, it is found that the above four types of rodless drainage and production processes have the advantages of effectively avoiding eccentric wear of pipes and rods in highly deviated wells and horizontal …

Development Characteristics And Enlightenment Of Eagle Ford Deep Shale Gas Reservoirs In North America, Yu Rongze, Wang Chenghao, Zhang Xiaowei, Hu Zhiming, Sun Yuping, Guo Wei, Duan Xianggang, Wang Meizhu

Coal Geology & Exploration

The large-scale development of shale gas with a buried depth of less than 3 500 m within the overpressure Wufeng-Longmaxi Formation has been realized in Sichuan Basin, and the effective development of shale gas resources with a buried depth of 3 500-4 000 m is being explored currently. Eagle Ford is an emerging deep shale oil & gas reservoir, which is comparable to the domestic medium-deep development regions and deep exploration regions, and its development technology policy and learning curve are available for reference. The parameters of drilling, fracturing, production and cost of 6 223 wells are analyzed in the …

Key Technology And Engineering Demonstration For Cascade Utilization Of Gas In Key Coal Mining Areas Of Shanxi Province, China, Li Guofu, Li Chao, Huo Chunxiu, Yan Zhiming, Zhang Diankun, Wang Chaoshuai, Wang Zheng

Coal Geology & Exploration

The key coal mining areas of Shanxi Province, including Jincheng, Yangquan, Xishan, Fenxi and Lu’an, are the main implementation sites of the “13th Five-Year” national science and technology major project “Demonstration Project of Coordinated Development of Coalbed Methane and Coal in Key Coal Mining Areas of Shanxi”. Relying on the high-end platform of the national science and technology major project, a series of technologies for cascade utilization of coal mine gas have been developed and demonstrated to guide the enhancement of gas drainage and utilization from 6.02 billion m³ and 2.23 billion m³ in 2015 to 6.403 billion …

Reservoir Forming Characteristics And Favorable Area Evaluation Of Deep Coalbed Methane In Daning-Jixian Block, Li Shuguang, Wang Chengwang, Wang Hongna, Wang Yubin, Xu Fengyin, Guo Zhidong, Liu Xinwei

Coal Geology & Exploration

The No.8 coal with a buried depth of more than 2 000 m of Lower Permian Taiyuan Formation in Daning-Jixian block, eastern margin of Ordos Basin is the first deep CBM field with an output of 100 billion m³ in China, but the reservoir forming characteristics of deep CBM are still unclear. In this paper, geological information, test and production data are synthetically applied to study the characteristics of deep CBM reservoir formation and evaluation of favorable areas. The results show that the deep coal reservoir in the study area is extensively distributed, with large thickness and high degree …

Analysis On Influencing Factors Of Single/Multi-Layer Development Of Coalbed Methane Field: A Case Study Of Baode Block, Zhang Lei, Xu Fengyin, Li Ziling, Zhang Wei, Hou Wei, Zhang Qingfeng, Zhang Wen, Fan Hongbo, Li Yongchen

Coal Geology & Exploration

Baode Block in the eastern margin of Ordos Basin is the first coalbed methane field of middle-low rank coal with 500 million cubic meters of production capacity constructed and reached in China, and it is also a benchmark in the coalbed methane industry there. During the development of Baode Block, good results are obtained by the commingled development of two sets of main coal layers, which are better than that of single-layer development. However, poor development result is obtained locally in the commingled development of some wells under the same development conditions, which is poorer than that of single-layer development. …