scholarly journals Characterization of fines produced during drainage of coalbed methane reservoirs in the Linfen block, Ordos Basin

2020 ◽  
Vol 38 (5) ◽  
pp. 1664-1679
Author(s):  
Aoxiang Zhang ◽  
Daiyong Cao ◽  
Yingchun Wei ◽  
Thomas E Rufford
Keyword(s):  
Coalbed Methane ◽  
Fine Particles ◽  
Ordos Basin ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Burial Depth ◽  
Main Components ◽  
Coal Reservoir ◽  
Casing Pressure ◽  
Coal Fines

Coal fines produced during drainage of coalbed methane reservoirs can affect the permeability of the coal reservoir and damage production facilities such as downhole pumps, shafts, and valves. Thus, to clarify the mechanism of coal fines output is very important to high production of coalbed methane. The characteristics of coal fines can be used to identify the sources of the coal fines and to develop reasonable means of controlling coal fines output. In this study, different coal fines characteristics were investigated to reveal the output mechanism of coal fines. The coal fines samples were collected from 16 coalbed methane wells, which located in Eastern Ordos Basin of China. And the wells are in different drainage stages. The coal fines samples were analyzed by using transmission light microscopy, reflection polarized optical microscopy, laser particle size analysis, X-ray diffraction, and scanning electron microscopy with energy dispersive X. The results show that the concentration of coal fines is in the range of 3–8% (volume percent). The sizes of the coal fine particles tended to be below 200 µm. The main components of pulverized coal are vitrinite and inorganic minerals and the average content of inorganic minerals account for 50.56% and the standard deviation is 0.0685. The morphology analysis results show that the shape of coal fines is different in different parts of the coalbed methane wells. The coal fines concentration increases with the increase in the thickness of the deformed coal, and decreases with the increase in the burial depth. The concentration of coal fines becomes higher with the increase of casing pressure and coal fines concentration increases with the increase of the variation of bottom hole pressure.

Impact of severity of ruminal acidosis on feed-sorting behaviour of beef cattle

2014 ◽  
Vol 54 (9) ◽  
pp. 1238 ◽  
Author(s):  
T. J. DeVries ◽  
T. Schwaiger ◽  
K. A. Beauchemin ◽  
G. B. Penner
Keyword(s):  
Dry Matter ◽  
Fine Particles ◽  
Particle Size Analysis ◽  
Dry Matter Intake ◽  
Size Analysis ◽  
Base Period ◽  
Ruminal Ph ◽  
Ruminal Acidosis ◽  
Particle Separator ◽  
Angus Heifers

The objective of this study was to determine how feed sorting changes in response to the severity of an induced episode of acute ruminal acidosis. Sixteen Angus heifers (261 ± 6.1 kg; bodyweight (BW) ± s.e.m.) were adapted to a high-grain diet (9% forage) before a ruminal acidosis challenge. Ruminal acidosis was induced by restricting feed to 50% of dry matter intake (DMI) as a proportion of BW for 24 h, followed by an intra-ruminal infusion of ground barley at 10% of DMI as a proportion of BW. Ruminal pH and feed sorting were monitored for 8 days (Base) before the challenge and on the challenge (CH) day. Ruminal pH data (duration (min) and area above the curve (min × pH) of pH <5.5) were recorded using an indwelling measurement system. To assess feed sorting, feed and orts were sampled daily and subjected to particle-size analysis. The particle separator had three screens (19, 8, 1.18 mm) and a bottom pan, resulting in four fractions (long, medium, short, fine). Sorting (%) was calculated as the actual intake/predicted intake of each particle fraction. During the Base period and the CH day, heifers sorted for long, medium and short particles, and sorted against fine particles. During the Base period, heifers experienced ruminal pH <5.5 for 489 ± 73 min/day with an area of 154 ± 29 (pH × min)/day; on the CH day, the duration increased to 1020 ± 75 min/day with an area of 631 ± 102 (pH × min)/day. A greater change in duration of pH <5.5 was associated with a greater increase in sorting for long and medium particles. A greater change in the area of pH <5.5 was associated with a greater increase in sorting for long particles and against fine particles. Overall, results show that cattle that experienced a greater degree of acidosis partially coped by sorting their ration more to consume a greater proportion of long, fibrous particles.

Analogy Analysis of Coalbed Methane Reservoir-Forming Conditions in Jixi Basin

2015 ◽  
Vol 733 ◽  
pp. 96-99 ◽  
Author(s):  
Yu Shuang Hu ◽  
Yu Gang Hao ◽  
Hui Ting Hu
Keyword(s):  
Coalbed Methane ◽  
The United States ◽  
Gas Content ◽  
Burial Depth ◽  
Oil Drilling ◽  
Black Warrior Basin ◽  
Reservoir Conditions ◽  
Coalbed Methane Reservoir ◽  
Dip Angle ◽  
Coal Reservoir

Based on coalbed methane geology theory, make use of coal and oil drilling data, from both of the coal reservoir characteristics and conservation conditions, Through comparative analysis of a number of geological factors of coalbed thickness, burial depth, metamorphic grade, gas content, roof and floor lithology, dip angle, etc, and found that there are many similarities between Jixi Basin and Black Warrior Basin in the United States of coalbed methane reservoir conditions. Compared to Black Warrior Basin, the advantages of Jixi Basin are that the coal metamorphism degree is high, the tired and single coalbed are thick, the closeness of roof and floor are good, the fault development and coalbed gas content are similar to it; the disadvantages of Jixi Basin are that the formation dip angle is large, the pressure gradient and permeability are small.

scholarly journals In Situ Stress Distribution and Its Control on the Coalbed Methane Reservoir Permeability in Liulin Area, Eastern Ordos Basin, China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Peng Feng ◽  
Song Li ◽  
Dazhen Tang ◽  
Liangjun Wu ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Ordos Basin ◽  
In Situ Stress ◽  
Burial Depth ◽  
Lateral Stress ◽  
High Permeability ◽  
Depth Zone ◽  
Stress Coefficient ◽  
Lateral Stress Coefficient

Permeability is one of the important factors that affect the production efficiency of coalbed methane, and it is mainly controlled by in situ stress. Therefore, it is very essential to study the in situ stress and permeability for the extraction of coalbed methane. Based on the injection/falloff well test and in situ stress measurement of 35 coalbed methane wells in the Liulin area in the east of the Ordos basin, the correlations between initial reservoir pressure, in situ stress, lateral stress coefficient, permeability, and burial depth were determined. Finally, the distribution characteristics of in situ stress and its influence on permeability were analyzed systematically. The results show that with the increase of burial depth, the initial reservoir pressure and in situ stress both increase, while the lateral stress coefficient decreases. The permeability variation is related to the type of stress field in different burial depths, and its essence is the deformation and destruction of coal pore structures caused by stress. The distribution characteristics of in situ stress at different depths and its effect on permeability are as follows: at depths < 800   m , the horizontal principal stress is dominant ( σ H ≥ σ v > σ h ) and the permeability is a simple decreasing process with the increase of the depth; at depths > 800   m , the vertical stress is dominant ( σ v ≥ σ H > σ h ). The permeability of most coal is very small due to the large in situ stresses in this depth zone. However, because of the stress release at the syncline axis, coal with high permeability is still possible at this depth zone. Due to the existence of high permeability data points at burial depth (>800 m) and the fitting relationship between permeability and vertical stress, the maximum and minimum horizontal principal stress is poor. However, the coal permeability and lateral stress coefficient show a good negative exponential relationship. This indicates that the lateral stress coefficient can be used to predict permeability better.

scholarly journals Characteristics of tectonic deformation in the Daning-Jixian region, eastern Ordos Basin: Implications for the exploration and development of coalbed methane

2018 ◽  
Vol 37 (3) ◽  
pp. 907-921
Author(s):  
Changgui Li ◽  
Bo Jiang ◽  
Wei Ju ◽  
Guoxi Cheng ◽  
Yu Song
Keyword(s):  
Coalbed Methane ◽  
Ordos Basin ◽  
Methane Content ◽  
Tectonic Deformation ◽  
Lower Permian ◽  
Burial Depth ◽  
The West ◽  
Eastern Margin ◽  
Middle Slope ◽  
Exploration And Development

Eastern Ordos Basin is an important region for the development of Carboniferous-Permian coalbed methane in China; however, there are significant differences of the coalbed methane exploration and development prospects among different regions within eastern Ordos Basin due to the multiple tectonic movements. In this study, the No. 5 coal of the Shanxi Formation of the Lower Permian in the Daning-Jixian region was selected for analysis. The influences of structures on coalbed methane content and permeability of coalbed methane reservoirs in the Daning-Jixian region were discussed and the favorable target areas for coalbed methane development were determined based on the analysis of tectonic characteristics and evolution. The results indicate that the main structures in this region extend in the NE–NNE direction with distinct E-W-trending zoning, which can be specifically divided into, from the east to the west, the fault depression zone in basin margins, the gentle fold zone in basin slopes, and the gentle slope zone. The formation and evolution of the structures in this area are primarily formed during the Indosinian, the Yanshanian, and the Himalayan movement, and the tectonic movement during the Middle Yanshan Period is critical for the formation of the structural frameworks. The coalbed methane contents in the No. 5 coal increase from the east to the west; therefore, low gas contents are found in the eastern margin zone, while the Yaoqu-Wucheng zone of middle slope belt displays high coalbed methane contents. The permeability is relatively high in the eastern margin zone and in the Mingti-Yangjiahe region of the middle slope zone, where there exist relatively strong structural deformations. The Guyi and Mingzhu blocks are selected as the favorable target areas for coalbed methane exploitation by a comprehensive analysis of burial depth, coalbed methane content, and the permeability.

Oil Well Cement Developed from Common Cement: Physical, Chemical and Mineral Characterization

2014 ◽  
Vol 805 ◽  
pp. 558-563 ◽  
Author(s):  
Danielle Nascimento Silva Oliveira ◽  
Ulisses Targino Bezerra ◽  
S.L.D. Beltrão ◽  
Alexsandra C. Chaves ◽  
Ana M.G.D. Mendonça ◽  
...  
Keyword(s):  
Setting Time ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Oil Well ◽  
X Ray Diffraction ◽  
Hydration Kinetics ◽  
Oil Well Cement ◽  
New Type ◽  
Main Components ◽  
Well Cement

This study aims to characterize a new type of cement, produced from the mixture of common Portland cements, which could be used as an option in the cementing of oil wells. To enable this study a linear programming method was used for the composition of the new cement, then, characterization tests were performed through particle size analysis by laser diffraction, chemical analysis by EDX, thermogravimetric analysis, X-ray diffraction, setting time, compressive strength. The results allowed the conclusion that the new formulated cement presented low C3A content, time setting superior to the Portland Cement for Oil Well, thermal stability up to 500 °C, low hydration kinetics and content of the main components coherent to the ABNT specifications.

scholarly journals Geo-environmental problem of snow avalanche defensive structures in mudstone zones, Niigata Prefecture, Japan

2002 ◽  
Vol 27 ◽  
Author(s):  
K. Aoyama ◽  
P. Bhattarai ◽  
M. Fukuda ◽  
J. Oku ◽  
T. Sakai
Keyword(s):  
Shear Strength ◽  
Environmental Problem ◽  
Fine Particles ◽  
Clay Fraction ◽  
High Strength ◽  
Particle Size Analysis ◽  
Snow Avalanche ◽  
Degree Of Saturation ◽  
Size Analysis ◽  
Niigata Prefecture

Fence-type defensive structures are very common on highway hillsides in Japan. They are constructed to protect the highway mainly from snow avalanche. Initially, these structures behave well. However, as the time lapses, the foundation of these well designed structures weakens and collapses. The situation is further aggravated by the static load of accumulated thick snow cover behind them. As mudstone is the dominant rock type in the Niigata Prefecture, it is a challenging task for geotechnical engineers to cope with such a severe geo-environmental problem. Although the mudstone exhibits a high strength while it is dry and fresh, it becomes quite unstable after sometime. When it comes in contact with water and atmosphere repeatedly, it starts weathering. Consequently, its shear strength is reduced and cannot resist the imposed shear stress and moment, and ultimately fails. For the laboratory investigation, mudstone blocks of various sizes were collected from the two typical mudstone areas: the Matsunoyama area and Nagaoka area in the Niigata Prefecture. These samples were sub merged and then dried alternately for several cycles. The particle size analysis of the weathered material showed that the proportion of fine particles increased with the degree of weathering. The laboratory tests of these samples exhibited a decrease in shear strength with an increasing degree of saturation. The periodic swelling and contraction of the clay fraction leads to volume change of foundation inducing its further weathering.

Nanoscale Pore Structure Characteristics of Deep Coalbed Methane Reservoirs and Its Influence on CH4 Adsorption in the Linxing Area, Eastern Ordos Basin, China

2021 ◽  
Vol 21 (1) ◽  
pp. 43-56
Author(s):  
Xiang-Dong Gao ◽  
Yan-Bin Wang ◽  
Xiang Wu ◽  
Yong Li ◽  
Xiao-Ming Ni ◽  
...  
Keyword(s):  
Pore Structure ◽  
Adsorption Capacity ◽  
Coalbed Methane ◽  
Ordos Basin ◽  
Rapid Decline ◽  
Burial Depth ◽  
Coal Rank ◽  
Coal Seams ◽  
Isothermal Adsorption ◽  
Nanoscale Pore

The high gas content of deep coal seams is a driving force for the exploration and development of deep coalbed methane (CBM). The nanoscale pores, which are the main spaces for adsorption and storage of CBM, are closely related to the burial depth. Based on integrated approaches of vitrinite reflectance (Ro), maceral composition, scanning electron microscope (SEM), proximate analysis, fluid inclusion test, low-temperature N2 adsorption–desorption, and CH4 isothermal adsorption, the nanoscale pore structure of coals recovered at depths from 650 to 2078 m was determined, and its influence on the CH4 adsorption capacity was discussed. The results show that the coal rank has a good linear relationship with the current burial depth of the coal seams; that is, the influences of the burial depth on the coals can be reflected by the influences of the coal rank on the coals. With the increase in the coal rank, the moisture and volatile content decrease, and the fixed carbon content increases. The variation in the pore volume and specific surface area with the increase in the coal rank can be divided into two stages: the rapid decline stage (when 0.75%<Ro < 1.0%), dominated by the compaction and gelatinization, and the slow decline stage (when 1.0%<Ro < 1.35%), characterized by the low stress sensitivity and the mass production of secondary pores. The percentage of micropores increases throughout the process. When 10 nm is taken as the boundary, the nanoscale pores show different fractal features. When Ro < 1.0%, the fractal dimension (FD) of the micropores is close to 3. When Ro > 1.0%, the FD of the micropores is close to 2. This indicates that with the increase in the degree of coalification, the surface of the micropores is simpler. The above results show that the gas adsorption capacity of coal first slightly decreases (when 0.75% < Ro < 1.0%) and then increases (when 1.0% < Ro < 1.35%), and the coincident results are shown in the Langmuir volume (VL) test results.

scholarly journals Road Verge Vegetation and the Capture of Particulate Matter Air Pollution

Environments ◽  
2020 ◽  
Vol 7 (10) ◽  
pp. 93
Author(s):  
Lory Sillars-Powell ◽  
Matthew J. Tallis ◽  
Mike Fowler
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Air Quality ◽  
Fine Particles ◽  
Deposition Velocity ◽  
Particle Size Analysis ◽  
Traffic Density ◽  
Size Analysis ◽  
Herbaceous Plant ◽  
Road Verge

Urban air quality is considered a major issue in cities worldwide, with particulate matter (PM) recognised as one of the most harmful pollutants regarding human health. The use of plants to act as air filters and immobilise PM has been identified as a potential method to improve the air quality in these areas. The majority of the work has focused on trees, with the application of shrub and herbaceous species largely overlooked. Two contrasting leaf morphologies from a shrub and herbaceous plant species were sampled at four locations across Southampton (UK), from varying traffic conditions. Samples were analysed for the mass of PM captured, particle size, and elemental composition. These analyses were used to characterise the different sites and the plants’ effectiveness at immobilisation of PM. Captured PM mass was shown to be directly related to traffic density, with greater traffic density leading to higher levels of captured PM. PM origins were attributed to emissions from vehicles and the resuspension of particles by vehicle movement. The bulk of the PM mass was shown to originate from natural, crustal sources including large proportions of Al, Si, and/or Ca. Increases in elements from anthropogenic enhancement (such as Fe and Zn) were related to high traffic density. Particle size analysis identified that, despite the use of standard leaf-washing protocols with a final 2.5 µm filter, PM was dominated by fine particles (<2.5 µm physical diameter), with particles >10 µm rare. Bramble leaves were calculated to have a species-specific deposition velocity 0.51 cm s−1 greater than ivy, with deposition velocities calculated at 1.8 and 1.3 cm s−1 for ivy and 2.3 and 1.8 cm s−1 for bramble at Redbridge Road and Brinton’s Road, respectively. These values can allow for the more accurate modelling and estimation of the PM removal abilities of these plants.

Evaluation of the Gas Content of Coal Reservoirs with Geophysical Logging in Weibei Coalbed Methane Field, Southeastern Ordos Basin, China

2013 ◽  
Vol 734-737 ◽  
pp. 331-334
Author(s):  
Tao Tao Yan ◽  
Zhi Qiang Liu ◽  
Li Ren Xing ◽  
Yong Luo ◽  
Ya Dong Bai ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Gamma Ray ◽  
Ordos Basin ◽  
Measured Data ◽  
Gas Content ◽  
Burial Depth ◽  
Geophysical Logging ◽  
Natural Gamma ◽  
Geophysical Logs ◽  
Movement Intensity

Gas content is one of the most important factors in the process of exploration and development of coalbed methane (CBM). The relationships between gas content and characteristics of geophysical logs have been evaluated for the No. 5 coal seam in Weibei CBM field. It is found that the main well loggings that have good responses for gas contents are the compensating density, natural gamma-ray, compensating neutron, natural spontaneous potential and acoustic. A theoretical model was proposed to calculate the gas content by using these well logging data and as well as the burial depth. The calculated gas contents fits well with the measured data with a small relative-error of 0.38-5.05%. In the model, both tectonic movement intensity and the gas accumulation were taken into consideration. Key words: Coalbed methane, Weibei coalfield, Ordos Basin, Gas content, Geophysical logging

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