scholarly journals Study on Desorption Experiment and Desorption Model of Deep Shale Gas Containing Water

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zuping Xiang ◽  
Yangyang Ding ◽  
Xiang Ao ◽  
Zehua Cheng ◽  
Qianhua Xiao ◽  
...  
Keyword(s):  
Water Content ◽  
Shale Gas ◽  
Desorption Process ◽  
Pressure Drops ◽  
Adsorbed Gas ◽  
Desorption Hysteresis ◽  
The Impact ◽  
Adsorption Curve ◽  
Desorption Model ◽  
Water Contents

In this work, the methane desorption isothermal curves at different water contents on deep sampled from Western Chongqing of China were measured at pressures up to 65 MPa and at 130°C by the volumetric method. In the first instance, the desorption increases with the decrease of pressure, the adsorbed gas desorbs slightly with decreasing pressures from 65 to 30 MPa. When the pressure drops to 30–20 MPa, the desorption rate increases rapidly with the decrease of pressure and the desorption curve begins to separate from the adsorption curve, resulting in desorption hysteresis. At last, when the pressure is lower than 20 MPa, the desorption increases almost linearly with the further decrease of pressure, but eventually there will be some adsorbed gas which cannot be desorbed to form residual adsorbed gas. After that, the isotherm desorption data of CH4 was fitted using the improved desorption model. The fitting results showed that the improved desorption model can be used to describe the desorption process of deep shale gas containing water and has a strong applicability. In addition, the critical desorption pressure increases with increasing water content. When the water content is lower than 1%, the effect of the water content on the desorption of deep shale gas increases rapidly with increasing water content, as well as when the water content is greater than 1%, the impact changes slowly.

scholarly journals An empirical model for describing the influence of water content and concentration of sulfamethoxazole (antibiotic) in soil on the total net CO2 efflux

2020 ◽  
Vol 68 (4) ◽  
pp. 351-358
Author(s):  
Miroslav Fér ◽  
Radka Kodešová ◽  
Barbora Kalkušová ◽  
Aleš Klement ◽  
Antonín Nikodem
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Solution Treatment ◽  
Soil Microbial Activity ◽  
Soil Samples ◽  
Co2 Efflux ◽  
The Impact ◽  
Water Contents ◽  
Soil Water Contents

AbstractThe aim of the study was to describe the impact of the soil water content and sulfamethoxazole, SUL, (antibiotic) concentration in soil on the net CO2 efflux. Soil samples were taken from topsoils of a Haplic Fluvisol and Haplic Chernozem. Soil samples were packed into the steel cylinders. The net CO2 efflux was measured from these soil columns after application of fresh water or SUL solution at different soil water contents. The experiments were carried out in dark at 20°C. The trends in the net CO2 efflux varied for different treatments. While initially high values for water treatment exponentially decreased in time, values for solution treatment increased during the first 250–650 minutes and then decreased. The total net CO2 effluxes measured for 20 hours related to the soil water content followed the second order polynomial functions. The maximal values were measured for the soil water content of 0.15 cm3 cm−3 (Haplic Fluvisol with water or solution, Haplic Chernozem with solution) and 0.11 cm3 cm−3 (Haplic Chernozem with water). The ratios between values measured for solution and water at the same soil water contents exponentially increased with increasing SUL concentration in soils. This proved the increasing stimulative influence of SUL on soil microbial activity.

scholarly journals Impacts of grass removal on wetting and actual water repellency in a sandy soil

2017 ◽  
Vol 65 (1) ◽  
pp. 88-98 ◽  
Author(s):  
Klaas Oostindie ◽  
Louis W. Dekker ◽  
Jan G. Wesseling ◽  
Violette Geissen ◽  
Coen J. Ritsema
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Profile ◽  
Water Repellency ◽  
Bare Soil ◽  
Soil Profiles ◽  
The Impact ◽  
Water Contents ◽  
Soil Water Contents

Abstract Soil water content and actual water repellency were assessed for soil profiles at two sites in a bare and grasscovered plot of a sand pasture, to investigate the impact of the grass removal on both properties. The soil of the plots was sampled six times in vertical transects to a depth of 33 cm between 23 May and 7 October 2002. On each sampling date the soil water contents were measured and the persistence of actual water repellency was determined of field-moist samples. Considerably higher soil water contents were found in the bare versus the grass-covered plots. These alterations are caused by differences between evaporation and transpiration rates across the plots. Noteworthy are the often excessive differences in soil water content at depths of 10 to 30 cm between the bare and grass-covered plots. These differences are a consequence of water uptake by the roots in the grass-covered plots. The water storage in the upper 19 cm of the bare soil was at least two times greater than in the grass-covered soil during dry periods. A major part of the soil profile in the grass-covered plots exhibited extreme water repellency to a depth of 19 cm on all sampling dates, while the soil profile of the bare plots was completely wettable on eight of the twelve sampling dates. Significant differences in persistence of actual water repellency were found between the grass-covered and bare plots.

Effect of Fracture Parameters on Desorption Properties of Shales

2013 ◽  
Vol 397-400 ◽  
pp. 252-256
Author(s):  
Kun Kun Fan ◽  
Ren Yuan Sun ◽  
Zi Chao Ma ◽  
Yun Fei Zhang ◽  
Yan Wei ◽  
...  
Keyword(s):  
Shale Gas ◽  
Horizontal Well ◽  
Experimental System ◽  
Desorption Rate ◽  
Desorption Process ◽  
Pressure Drops ◽  
Equilibrium Time ◽  
System Pressure ◽  
Shale Sample ◽  
Half Length

Horizontal well and hydraulic fracturing are the main technologies for shale gas development. The desorption properties of shales are very important data for shale gas development. In order to simulate the desorption process in shales with horizontal well and fractures, a new method for shale sample preparation and a new experimental system for the evaluation were developed. The effect of the number and half-length of fractures on the desorption rate and the desorption equilibrium time were measured when the system pressure drops from 9.2MPa to 7MPa. Experiments show that the initial desorption rate increases and the equilibrium time decreases with the increase of the number and half-length of fractures. Within the scope of the experiments, the number of fractures is more important than the half-length of fractures for the desorption rate.

scholarly journals Effect of reservoir pressure and total organic content on adsorbed gas production in shale reservoirs: a numerical modelling study

2022 ◽  
Vol 15 (2) ◽  
Author(s):  
Moataz Mansi ◽  
Mohamed Almobarak ◽  
Christopher Lagat ◽  
Quan Xie
Keyword(s):  
Numerical Modelling ◽  
Shale Gas ◽  
Organic Content ◽  
Gas Production ◽  
Reservoir Pressure ◽  
Adsorbed Gas ◽  
Total Organic Content ◽  
Simulation Results ◽  
Shale Reservoirs ◽  
The Impact

AbstractAdsorbed gas plays a key role in organic-rich shale gas production due to its potential to contribute up to 60% of the total gas production. The amount of gas potentially adsorbed on organic-rich shale is controlled by thermal maturity, total organic content (TOC), and reservoir pressure. Whilst those factors have been extensively studied in literature, the factors governing desorption behaviour have not been elucidated, presenting a substantial impediment in managing and predicting the performance of shale gas reservoirs. Therefore, in this paper, a simulation study was carried out to examine the effect of reservoir depth and TOC on the contribution of adsorbed gas to shale gas production. The multi-porosity and multi-permeability model, hydraulic fractures, and local grid refinements were incorporated in the numerical modelling to simulate gas storage and transient behaviour within matrix and fracture regions. The model was then calibrated using core data analysis from literature for Barnett shales. Sensitivity analysis was performed on a range of reservoir depth and TOC to quantify and investigate the contribution of adsorbed gas to total gas production. The simulation results show the contribution of adsorbed gas to shale gas production decreases with increasing reservoir depth regardless of TOC. In contrast, the contribution increases with increasing TOC. However, the impact of TOC on the contribution of adsorbed gas production becomes minor with increasing reservoir depth (pressure). Moreover, the results suggest that adsorbed gas may contribute up to 26% of the total gas production in shallow (below 4,000 feet) shale plays. These study findings highlight the importance of Langmuir isothermal behaviour in shallow shale plays and enhance understanding of desorption behaviour in shale reservoirs; they offer significant contributions to reaching the target of net-zero CO2 emissions for energy transitions by exhibiting insights in the application of enhanced shale gas recovery and CO2 sequestration — in particular, the simulation results suggest that CO2 injection into shallow shale reservoirs rich in TOC, would give a much better performance to unlock the adsorbed gas and sequestrate CO2 compared to deep shales.

Consistent plant residue removal causes decrease in minimum soil water content in a Mediterranean environment

Biologia ◽  
2013 ◽  
Vol 68 (6) ◽  
Author(s):  
Philip Ward ◽  
Margaret Roper ◽  
Ramona Jongepier ◽  
Maria Fernandez
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Ground Cover ◽  
Plant Residue ◽  
Residue Removal ◽  
The Impact ◽  
Water Contents ◽  
Soil Water Contents ◽  
Residue Retention

AbstractResidue retention and no-till farming have been widely adopted to reduce erosion risk, but residue retention in particular is becoming less common due to issues with weed control, and competing markets for residue such as bioenergy production. For this reason, the impact of residue removal on soil water contents in a sandy soil in a Mediterranean-type environment was evaluated. Crop residues were removed by burning or conventional tillage annually in autumn (April or May) from 2008 until 2011. Surface residue cover and soil water contents were measured in summer (February-March) every year from 2008 until 2012, at the time of minimum soil water content (approaching air-dry). After three years of residue removal, average ground cover in the subsequent summers (2011 and 2012) decreased from 78% to 51%, and surface soil water contents decreased from 5.1% to 3.1%. Tillage also significantly decreased ground cover (from 72% to 58%) and soil water (from 4.2% to 3.9%) during the same time period. Changes in surface cover and soil water content indicate that residue removal will have implications for soil health and sustainable crop production.

scholarly journals Impact of Geological Factors on Marine Shale Gas Enrichment and Reserve Estimation: A Case Study of Jiaoshiba Area in Fuling Gas Field

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Siyu Yu ◽  
Xixin Wang ◽  
Shaohua Li ◽  
Yuming Liu ◽  
Liming Xiao ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Shale Gas ◽  
Gas Content ◽  
Accurate Estimation ◽  
Gas Field ◽  
Adsorbed Gas ◽  
Marine Shale ◽  
Geological Factors ◽  
The Impact

Geological factors are key elements to control shale gas enrichment and influence the accurate estimation of shale gas reserve. However, the impact of the main geological factors, such as porosity, mineralogy, and organic matter, on marine shale gas enrichment and reserve calculation has not yet been fully clarified. Herein, we measured gas adsorption, porosity, mineralogical composition, and total organic carbon content of the marine shale samples from the Jiaoshiba area of Fuling gas field in Sichuan Basin, South China, and investigate the relationships between the geological factors and the adsorbed gas content. The results show that adsorbed gas content is positively correlated with total organic carbon and porosity; the larger specific surface area of samples with more clay minerals essentially contributes to shale gas enrichment. Additionally, the sealing of faults imposes a significant impact on shale gas accumulation. The probability volume method was applied to calculate the shale gas reserve. The reserves of P90 (the most pessimistic reserve), P50 (the most likely reserve), and P10 (the most optimistic reserve) were calculated, respectively, which provides useful information to reduce the risk in shale gas development.

scholarly journals Adsorption Characteristics and Controlling Factors of CH4 on Coal-Measure Shale, Hedong Coalfield

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 63
Author(s):  
Weidong Xie ◽  
Meng Wang ◽  
Hongyue Duan
Keyword(s):  
Organic Matter ◽  
Adsorption Capacity ◽  
Mineral Composition ◽  
Shale Gas ◽  
Total Content ◽  
Coal Measure ◽  
Gas Reservoirs ◽  
Quartz Content ◽  
Adsorption Characteristics ◽  
Adsorbed Gas

Adsorbed gas is one of the crucial occurrences in shale gas reservoirs; thus, it is of great significance to ascertain the adsorption capacity of shale and the adsorption characteristics of CH4. In this investigation, the Taiyuan–Shanxi Formations’ coal-measure shale gas reservoir of the Carboniferous–Permian era in the Hedong Coalfield was treated as the research target. Our results exhibit that the shale samples were characterized by a high total organic carbon (TOC) and over to high-over maturity, with an average TOC of 2.45% and average Ro of 2.59%. The mineral composition was dominated by clay (62% on average) and quartz (22.45% on average), and clay was mainly composed of kaolinite and illite. The Langmuir model showed a perfect fitting degree to the experimental data: VL was in the range of 0.01 cm3/g to 0.77 cm3/g and PL was in the range of 0.23–8.58 MPa. In addition, the fitting degree depicted a linear negative correlation versus TOC, while mineral composition did not exhibit a significant effect on the fitting degree, which was caused by the complex pore structure of organic matter, and the applicability of the monolayer adsorption theory was lower than that of CH4 adsorption on the mineral’s pore surface. An apparent linear positive correlation of VL versus the TOC value was recorded; furthermore, the normalized VL increased with the growth of the total content of clay mineral (TCCM), decreased with the growth of the total content of brittle mineral (TCBM), while there was no obvious correlation of normalized VL versus kaolinite, illite and quartz content. The huge amount of micropores and complex internal structure led to organic matter possessing a strong adsorption capacity for CH4, and clay minerals also promoted adsorption due to the development of interlayer pores and intergranular pores.

scholarly journals Review of Formation and Gas Characteristics in Shale Gas Reservoirs

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5427
Author(s):  
Boning Zhang ◽  
Baochao Shan ◽  
Yulong Zhao ◽  
Liehui Zhang
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Shale Gas ◽  
Physical Parameters ◽  
Gas Reservoirs ◽  
Shale Formations ◽  
Adsorbed Gas ◽  
Shale Gas Reservoirs ◽  
Longmaxi Shale

An accurate understanding of formation and gas properties is crucial to the efficient development of shale gas resources. As one kind of unconventional energy, shale gas shows significant differences from conventional energy ones in terms of gas accumulation processes, pore structure characteristics, gas storage forms, physical parameters, and reservoir production modes. Traditional experimental techniques could not satisfy the need to capture the microscopic characteristics of pores and throats in shale plays. In this review, the uniqueness of shale gas reservoirs is elaborated from the perspective of: (1) geological and pore structural characteristics, (2) adsorption/desorption laws, and (3) differences in properties between the adsorbed gas and free gas. As to the first aspect, the mineral composition and organic geochemical characteristics of shale samples from the Longmaxi Formation, Sichuan Basin, China were measured and analyzed based on the experimental results. Principles of different methods to test pore size distribution in shale formations are introduced, after which the results of pore size distribution of samples from the Longmaxi shale are given. Based on the geological understanding of shale formations, three different types of shale gas and respective modeling methods are reviewed. Afterwards, the conventional adsorption models, Gibbs excess adsorption behaviors, and supercritical adsorption characteristics, as well as their applicability to engineering problems, are introduced. Finally, six methods of calculating virtual saturated vapor pressure, seven methods of giving adsorbed gas density, and 12 methods of calculating gas viscosity in different pressure and temperature conditions are collected and compared, with the recommended methods given after a comparison.

scholarly journals Numerical Simulation of Non-Homogeneous Viscous Debris-Flows Based on the Smoothed Particle Hydrodynamics (SPH) Method

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2314 ◽  
Author(s):  
Shu Wang ◽  
Anping Shu ◽  
Matteo Rubinato ◽  
Mengyao Wang ◽  
Jiping Qin
Keyword(s):  
Debris Flow ◽  
Water Content ◽  
Smoothed Particle Hydrodynamics ◽  
Debris Flows ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
The Impact ◽  
Kinetic And Potential Energies

Non-homogeneous viscous debris flows are characterized by high density, impact force and destructiveness, and the complexity of the materials they are made of. This has always made these flows challenging to simulate numerically, and to reproduce experimentally debris flow processes. In this study, the formation-movement process of non-homogeneous debris flow under three different soil configurations was simulated numerically by modifying the formulation of collision, friction, and yield stresses for the existing Smoothed Particle Hydrodynamics (SPH) method. The results obtained by applying this modification to the SPH model clearly demonstrated that the configuration where fine and coarse particles are fully mixed, with no specific layering, produces more fluctuations and instability of the debris flow. The kinetic and potential energies of the fluctuating particles calculated for each scenario have been shown to be affected by the water content by focusing on small local areas. Therefore, this study provides a better understanding and new insights regarding intermittent debris flows, and explains the impact of the water content on their formation and movement processes.

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