Earth Sciences Commons^™

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 …

Influence Of The Freezing-Thawing Cycles On Soil-Water Characteristics Of Soil In Open-Pit Mine Dumping Sites, Wang Xuedong, Li Shiyu, Sun Yanfeng, Ye Guo

Coal Geology & Exploration

In order to study the unsaturated soil-water characteristics of soil under freezing-thawing cycles, the soil in Yuanbaoshan open-pit mine dumping site was selected as the research object. The variation of matrix suction and structure of soil under different water content after different freezing-thawing cycles was studied. The results show that during the same freezing-thawing cycles, the matrix suction increases with the decrease of water content, and the range increases gradually. The soil-water characteristic curve can be divided into sensitive stage, sub-sensitive stage and insensitive stage. With the increase of freezing-thawing cycles, the curvature of soil-water characteristic curve increases first and …

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, 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, 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 …

Acquisition Platform Of Frequency Domain Ip Signal, Fu Guohong, Zhang Qianfeng, Cheng Hui, Xie Tiancai

Coal Geology & Exploration

In order to improve the versatility of the induced polarization(IP) signal receiver of traditional frequency domain, a signal acquisition platform was designed, which can acquire and process IP signals of frequency domain such as variable-frequency signals, dual-frequency IP signals, and pseudo-random multi-frequency IP signals and so on. Hardware circuits were established based on STM32 to execute low-pass filtering, program-controlled amplification, analog-to-digital conversion, and data communication. The host computer was developed in LabVIEW to achieve parameter settings, digital filtering, spectrum analysis, amplitude measurement and calculation to obtain target parameters such as PFE, and has waveform display and playback, data storage and …

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 …

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 …

Art And The Environment, Ellen Dexter, Lydia Dexter

Honors Program: Expanded Learning Clubs

After school club that teaches the importance of sustainable practices and conversation activities through art projects and imagination.

Student Support Program Outputs, Outcomes And Impacts Report

Daugherty Water for Food Global Institute: Administrative Materials

The Robert B. Daugherty Water for Food Global Institute (DWFI) inititated its Postdoctoral and Student Support Programs in 2014. The following details their achievements.

Round One -- The institute first provided undergraduate, graduate student and postdoctoral support to faculty who were selected following a call for proposals in 2014. Support was awarded for two postdocs, five graduate students, and two projects with undergraduate students. By FY19 a small amount of support continues for Francisco Munoz-Arriola’s program. Outputs include presentations, grants and publications. The other faculty who have received support are: Vijendra Boken, UNK Geography & Earth Science; Carrick Detweiler, UNL …

The Prairie Post Quarterly Newsletter Of The High Plains Regional Climate Center- October 2019, Crystal J. Stiles, Rezaul Mamood, Logan Winters, Paul Flanagan, Natalie Umphlett

Prairie Post: Quarterly Newsletter of the High Plains Regional Climate Center

Inside this issue:

Message from the director........................................1

Staff spotlight...........................1

Workshops focus on climate services in Kansas....................2

Research highlights................3

AMS Annual Meeting.............3

Update on regional climate conditions..................................4

New ACIS Climate Summary Maps available..........................5

Track precipitation with CLIMOD.......................................5

Recent and upcoming travel and activities.............................6

Removal Of Selected Pharmaceuticals And Personal Care Products In Wastewater Treatment Plant In Jordan, Othman Al-Mashaqbeh, Diya Alsafadi, Sahar Dalahmeh, Shannon L. Bartelt-Hunt, Daniel D. Snow

Nebraska Water Center: Faculty Publications

The largest wastewater treatment plant in Jordan was monitored in the summer to determine the removal of pharmaceuticals and personal care products (PPCPs). Grab samples were collected from the influent and effluent of As-Samra Wastewater Treatment Plant (WWTP). Liquid chromatography and tandem mass spectrometry (LC–MS/MS) were utilized to determine the concentrations of 18 compounds of pharmaceuticals and personal care products (PPCPs). The results showed that 14 compounds were detected in the collected samples from the influent and effluent of As-Samra WWTP. These compounds are 1,7-dimethylxanthine, amphetamine, acetaminophen, caffeine, carbamazepine, cimetidine, cotinine, diphenhydramine, methylenedioxymethamphetamine (MDMA), morphine, phenazone, sulfamethazine, sulfamethoxazole, thiabendazole, and …

An Engineering Geological Anatomy Of The Padma River Bank Failure And Erosion, 2018: A Case Study Of Naria Bank Section, Bangladesh, Mir Fazlul Karim, Nazrul I. Khandaker, Shahidul Haque, M. Zillur Rahman, Muhammad Qumrul Hassan, Asm Maksud Kamal, Masud Ahmed, Belal A. Sayeed

Publications and Research

The Naria town of Bangladesh is developed on the right bank of the Padma River. The bank is an old natural levee of Meghna River. The Holocene-Recent geology of Naria is actively dominated by the fluvial processes of Ganges-Brahmaputra-Meghna River system where the deltaic sediments are characterized as unconsolidated fine sand and silt, covered by thin veneer of clayey silt and loam. The annual volume of water discharge and flow dynamics are dependent on the intensity of the rainfall, runoff and the length of dry winter. Excessive river bank erosion, channel avulsion, renewed submergence of floodplains, and formation of natural …

Stakeholders’ Perceptions Of Geographical Criteria For Loblolly Pine Management For Bioenergy Production In Virginia, Meghann Smith, Gia Nguyen, Taylor Wieczerak, Bernabas Wolde, Pankaj Lal, John Munsell

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

This study analyzed the perceptions of four stakeholder groups (forest landowners, private forest consultants, forest management researchers or educators, and federal or state agency foresters), regarding their management practices and preferred geographic growing conditions of loblolly pine in Virginia by combining AHP (analytical hierarchy process) and regression modeling. By ranking the importance of different geographical conditions for managing loblolly pine, we aimed to identify ways to support loblolly growth as a potential feedstock for biofuel generation. We achieved this through collecting survey responses from 43 stakeholders during the 2019 Virginia Forestry Summit. The results showed that the landowner, researcher/educator, and …

A Technical Overview Of The Kentucky Mesonet, Rezaul Mahmood, Megan Schargorodski, Stuart Foster, Andrew Quilligan

High Plains Regional Climate Center: Staff Publications

The Kentucky Mesonet is a research-grade weather and climate observing network with redundant sensors that monitors the near-surface atmosphere at 71 locations across Kentucky. The network measures temperature, precipitation, solar radiation, relative humidity, barometric pressure, and wind speed and direction every 5 min, with soil moisture and soil temperature measured every 30 min. In addition, it operates a camera at selected locations. All observations are transmitted via cellular modem every 5 min and become available to the general public through the World Wide Web within seconds after arrival at Kentucky Mesonet’s Network Operations Center. In between arriving at the IT …

Umphlett Qci Sept 2019, Natalie Umphlett

High Plains Regional Climate Center: Staff Publications

Highlights for the Basin

Temperature and Precipitation Anomalies

Soil Moisture Conditions

Delayed/Prevented Planting

Forage Production

Infrastructure

Temperature

Precipitation

The Water/Energy Nexus: Climate, Consumption And Ecosystem Services, Hildegaard D. Link

Dissertations, Theses, and Capstone Projects

Water and energy are drivers of living systems. This work provides an assessment of the Water Energy Nexus in the United States, comparing the well-watered north-east and the arid west. Electric grid systems are most stressed on hot summer afternoons. Grid stress can lead to cascading failures of electricity, water and wastewater treatment systems. (Zimmerman, 2017) Water for power generation and/or water supply depend on ecosystem services. The ecosystem services and resource trade-offs embedded in provision of a watt of power and an ounce of potable water, however, have yet to be comprehensively enumerated nor have the cost relationships been …

Effect Of Nmr Technology-Based Ultrasonic Frequency On Stimulated Cracking Of Coal, Ma Huiteng, Zhai Cheng, Xu Jizhao, Sun Yong

Coal Geology & Exploration

In order to further study the effect of ultrasonic frequency on the stimulated cracking effect of coal, the paper conducted the crack experiment on the original coal samples by using the ultrasonic generation meter, and measured the coal by using the NMR equipment through analyzing the T₂ curve, the changes of pore structure before and after coal sample cracking were deeply studied. The results show that the pore structure of coal can be effectively improved by the ultrasonic wave. After the crack induced by the ultrasonic wave, the pore quantity inside the coal increased and the total porosity, effective …

Advances On Geological-Geochemical Research Of Coal-Type Uranium In China, Zhou Xianqing, Qin Yong, Lu Lu

Coal Geology & Exploration

There is a huge gap in uranium resources in China. Only developing traditional uranium resources is unable to meet the increasing demand in energy and national defense construction. The exploitation and utilization of coal-type uranium resources can relieve the pressure of demand for uranium resources to a certain extent. By summarizing the research results of coal-type uranium in recent years, the ore location, uranium content range, formation time and distribution range of coal-bearing strata of major coal-type uranium deposits in China, and the definition criteria of coal-type uranium are given, which provides a basis for the classification of coal-type uranium …

Structural Optimization And Simulation Analysis Of High Reliability Wire-Line Coring Drilling Tools For Submarine Drilling Rigs, Wang Jialiang, Peng Fenfei, Wan Buyan, Zhou Yun

Coal Geology & Exploration

In order to improve the working reliability of wire-line coring drilling tools used in submarine drilling rigs, based on the particularity of submarine environment, from the aspect of improvement of the single action performance of the single action mechanism and the working reliability of the suspension mechanism, the structural optimization of the single action mechanism was carried out, the numerical simulation analysis of the suspension mechanism was conducted by using ABAQUS simulation. The results show that the improved bearing assembly structure can restrain sea water corrosion, improve the centering effect of arbor and enhance the flexibility of bearing assembly. The …

Damage Mechanism And Countermeasures Of Reservoir With Abnormal Pickup Of Cbm Flow Pressure In Well, Jia Huimin, Hu Qiujia, Qi Kongjun, Qin Mengfu, Mao Chonghao, Zhang Guangbo

Coal Geology & Exploration

The reasonable control of the casing pressure and the bottom-hole pressure and the reasonable depressurization of reservoir pressure is the key technology for the CBM development. The pickup of the bottom-hole flow pressure(BHFP) will restrain CBM' desorption, lead to reservoir permeability damage and reduce the production of CBM wells. Based on production practice of Fanzhuang block in Qinshui basin, this paper puts forward the cause of a CBM abnormal well type, pickup of the BHFP, clarifies the damage mechanism of the pickup of the BHFP through theoretical research and field data analysis, and puts forward the evaluating method of the …

Analysis And Application Of Key Influencing Factors Of Cbm Well Fracturing Effects In Shizhuang Area, Qinshui Basin, Xue Haifei, Zhu Guanghui, Wang Wei, Lu Xiaoxia, Wang Minghao, Wang Yanbin

Coal Geology & Exploration

CBM fracturing effect has many influencing factors. Development effect with the same technology is different in different area. Based on a large amount of geological and engineering data in Shizhuang block, it was found that high geo-stress affects fracture extension and support in CBM fracturing, and difference between horizontal stress affects fracture direction and morphology. Coal seam with poor coal structure can produce large amount of gum during fracturing, which will block the diversion channel and result in poor fracturing effect. Engineering factors affecting fracturing effect mainly include the fracturing fluids performance, displacement, prepad fluid proportion and hole enlargement ratio. …

Influence Of Internal Friction Angle On Damage Constitutive Model Of Freeze-Thaw Rock, Yuan Chao, Zhang Huimei, Meng Xiangzhen, Yang Gengshe, Wu Luyuan

Coal Geology & Exploration

Based on Weibull random distribution and damage mechanics theory, starting from the characteristics of rock deformation process, the Drucker-Prager criterion was used to establish a damage constitutive model that can reflect the characteristics of rock various deformation stages. Through the conventional triaxial compression test of frozen-thawed sandstone, the Mohr stress circle was used to obtain the cohesion and internal friction angle of the sandstone under different freeze-thaw cycles. The model theoretical curve and the test curve of freeze-thaw sandstone were compared to verify the model rationality. By varying the internal friction angle, whether the friction angle has an effect on …

Accurate Test Technology And Device For Coal Seam Gas Content In Long Boreholes In Underground Coal Mines, Sun Siqing, Zhang Qun, Long Weicheng, Zheng Kaige, Hei Lei

Coal Geology & Exploration

In order to get actual gas content of underground coal mine during large-scale advanced detection, the sealed coring method for gas content was proposed. The sealed coring device of "three-cylinders, single motion and ball valve sealing" suitable for accurate test of gas content of long boreholes in underground coal mines was designed and trial-produced, the outer diameter of the device is 89 mm, and the diameter of the coal core can reach 38 mm, the pressure holding capacity of the sealed coring device is above 11 MPa, which satisfies the requirement of sealing sampling for the determination of coal seam …

Geological Characteristics And High Efficiency Development Technology Of Coalbed Methane In Duijiangnan Coal Mine, Guizhou Province, Gong Zewen

Coal Geology & Exploration

The development progress of coalbed methane in Duijiangnan mine field is slow. The main problems are low drilling efficiency, serious cementing leakage, long fracturing transformation period and low single well production in the block. Objectively evaluating the geological characteristics and development technology of coalbed methane is very im-portant for coalbed methane in the future. The coalbed thickness, coal body structure, reservoir pressure, gas content and permeability are systematically studied, combining with the past drilling, fracturing and drainage practices. It is proposed that directional wells are the main method of coalbed methane development in the coalfield. The coal seam M18 which …

Corrosion Behavior Analysis Of Sucker Rod For Coalbed Methane Wells In The Eastern Block Of Ordos Basin, Pang Bin, Wang Hanxiang, Lan Wenjian

Coal Geology & Exploration

In order to make clear the corrosion rule of sucker rod for coalbed methane wells in the eastern block of Ordos basin, the paper summarizes the corrosion types and corrosion intensities of the sucker rod, based on the test of produced gas, produced water, corrosion products and weight loss of sucker rod. The paper analyzes the effect of different drainage stages, coal seam and mineralization degree of water on the corrosion. The results of the research indicate that corrosion is mainly caused by CO₂ and H₂S originated from No.5 coal seam and No.11 coal seam. The corrosion …

Study On Uniaxial Compression Mechanical Properties Of Sandstone With Different Moisture Content And Wave Velocity Method, Duan Tianzhu, Ren Yaping

Coal Geology & Exploration

In order to investigate the mechanical properties and damage of sandstone under different uniaxial compression, the static uniaxial compression tests of five sandstones with different moisture content were carried out, and the physical and mechanical parameters were obtained. And the wave velocity of the sandstone samples with different moisture content were measured by ultrasonic detector. Then the sandstone was loaded to 80% peak intensity and then unloaded to 0. The acoustic wave velocity of sandstone was measured at this time. The damage was determined by acoustic wave method. The results show that the peak strength of sandstone under uniaxial compression …

A Method Of Random Noise Suppression Based On Compressed Sensing, Yang Liangang, Li Lingyun, Yang Yumei, Qu Yuanji, Yan Ke

Coal Geology & Exploration

With the development of high precision seismic exploration technology, the use of high fidelity methods to improve the SNR of seismic data becomes the key to denoising. Curvelet threshold method can effectively suppress random noise, but at the same time the method is easy to produce pseudo Gibbs shock phenomenon, resulting in local distortion of the signal, thus affecting the processing effect. To solve this problem, a method of seismic signal denoising based on compressing sensing(CS) is presented in this paper. The method uses the difference between sparse representation of random noise and effective signal in curvelet sparse domain to …

Channel Wave Advanced Detection Method Based On Kirchhoff Migration And Its Application, Zhao Yunpei, Wang Wei, Hou Xianhua

Coal Geology & Exploration

In order to detect the geological structures in the front of the working face 1199 in Gequan mine of Xingtai mining area, underground channel wave seismic exploration was used to conduct advanced detection, linear Radon transform was used to extract the reflection wave from the front of the roadway, parameter information of the surrounding rocks were obtained through velocity analysis in time domain, The abnormal geological bodies in the front of the roadway were imaged through Kirchhoff migration. The results indicated that there existed anomalies at 205 m and 237 m away from the geophone point G12 in the front …

Shale Gas Potential Of Yanguanjie Formation And Longtan Formation In Central And Southeastern Hunan Province, Cao Taotao, Deng Mo, Liu Hu, Huang Yanran, Stefan Andrew Hurssthouse

Coal Geology & Exploration

In order to reveal the shale gas potential and exploration direction of the marine-continental transitional shale in central and southeastern Hunan, samples were collected from the Lower Carboniferous Yanguanjie Formation and Upper Permian Longtan Formation, measurements were conducted on TOC, R_ran, kerogen carbon isotope, maceral composition, X-ray diffraction, scanning electron microscopy, porosity, permeability and methane sorption capacity. The results indicate that Yanguanjie Formation and Longtan Formation shale are at the mature stage, and mainly dominated by type Ⅲ kerogen. The Longtan shale generally has higher TOC content, while Yanguanjie shale has usually low TOC content. The minerals are …