Characteristics and generation mechanisms of coal fines in coalbed methane wells in the southern Qinshui Basin, China

Zhao, Xianzheng; Liu, Shiqi; Sang, Shuxun; Pan, Zhejun; Weiwei, Zhao; Yang, Yanhui; Hu, Qin; Yang, Yike

doi:10.1016/j.jngse.2016.07.063

Cited by 42 publications

(27 citation statements)

References 28 publications

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“…There is one type of model that treats the particle and the carrier fluid velocity the same [23,24,34,35]. This model cannot describe the phenomenon that the fluid is able to transport fines only if the velocity of water exceeds a certain minimum value [37]. For this reason, subsequent studies have introduced the velocity of fines (ω) and the critical water velocity.…”

Section: Modified Darcy Model For Water Flow With Coal Finesmentioning

confidence: 99%

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Numerical Simulation Study of Fines Migration Impacts on an Early Water Drainage Period in Undersaturated Coal Seam Gas Reservoirs

et al. 2019

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Coal fines migration exerts negative impacts on early water drainage of undersaturated coal seam gas (CSG) reservoirs. The complicated migration process results in ineffective and inaccurate forecast of coal fines production. Hence, a robust modelling tool is required to include the mechanisms of fines migration and to predict their impacts on rock and production. In this paper, fines migration in coal is categorized into three stages: generation, migration, and deposition processes. The corresponding models for different stages are established, including (1) a fines generation model, (2) the maximum fines-carrying concentration model and deviation factor of the modified Darcy model, (3) a fines deposition model, and (4) a dynamic permeability and porosity model. The above models are coupled with a water flow model, solved numerically using the finite difference method. Then, two dewatering strategies, including fast and moderate depressurization, are compared using the proposed models to study their effects on coal properties and following production. Finally, the production history of a CSG well in the Qinshui Basin, China, is utilized for history matching in a field case study. The simulation results indicate that new fines will be generated in a fast depressurization process and the water rate decline reduces the cleat permeability significantly. The newly generated fines can enhance the permeability temporarily, but they will block the flow channels and bring serious damage to the permeability when the water rate declines. The moderate depressurization strategy can produce the coal fines in a continuous mode, and the formation damage induced by fines deposition can be reduced to the acceptable level, which is the more reliable way to maintain well productivity. In addition, multiple well shut-in can trigger the irreversible fines deposition, reduce the permeability, and decrease the production rate.

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Section: Modified Darcy Model For Water Flow With Coal Finesmentioning

confidence: 99%

“…However, the improvement still does not show the significant difference of velocity between fines and water. For instance, Zhao et al obtained a group of data from laboratory tests, which reveals a linear relationship between the coal fines velocity and water velocity [37], written as…”

Section: Modified Darcy Model For Water Flow With Coal Finesmentioning

confidence: 99%

Numerical Simulation Study of Fines Migration Impacts on an Early Water Drainage Period in Undersaturated Coal Seam Gas Reservoirs

et al. 2019

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“…Speci cally, India has tremendous potential for the extraction of methane from coal beds (Rathi et al 2019). Concurrently, the CBM reservoirs with clay mineral deposits are highly susceptible to reservoir formation damage due to nes (inorganic minerals) and coal nes (tiny fragment from broken coal matrix) migration under hydrodynamic and thermodynamic forces Guo et al 2018;Huang et al 2018;Zhao et al 2018;Zhao et al 2016;Valentim et al 2016;Han et al 2015;Bai et al 2015;Guo et al 2015;Zeinijahromi et al 2012;Seidle 2011). Actually, kaolinite clay minerals are located in several sedimentary formations, especially in sandstone and carboniferous rocks, and moreover, kaolinite occurs through dissolution of feldspar at extreme temperature and geochemical alterations (Mahalingam et al 2019;Kanimozhi et al 2019a).…”

Section: Introductionmentioning

confidence: 99%

Permeability Damage and Supercritical Fluid Storage in the Cauvery Basin Neyveli Lignite Bed Containing Kaolinite Deposits during Alternative Injection of Brine and CO2

Rajkumar

Antony

Mahalingam³

et al. 2020

Preprint

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A laboratory based investigation has been conducted on permeability damage and CO2 storage or retention in the lignite core during alternative injection of brine and supercritical carbon dioxide. Moreover, anthracite and bituminous coal beds were focused by the scientific community for effective production and reservoir formation damage study. But, now-a-days, lignite based coal bed methane reservoirs have attracted attention for productive exploitation and formation collapse investigation. Hence, for this purpose, a single component injection two phase (Brine + Supercritical CO2) coreflood test analysis under alternative injections were performed to investigate the occurrence of lignite structural collapse, permeability damage, injectivity decline and CO2 retention as well. The experimental study reveals that, due to gravity segregation there is a high rate of fluid saturation in lignite core and also, moderate level of heat transfer coefficient was also noted. Also, lignite core structural collapse under the brine and supercritical CO2 injection at different velocities resulted in huge volume of coal and kaolinite fines concentration. Kaolinite and coal fines migration resulted in pressure change and permeability decline in lignite core. The suspensions produced were passed to microstructural analysis and it revealed that kaolinite fine particle tends to possess a leaflet geometrical structure, which obstructed the cleats and restricted the fluid flow. Subsequently, hysteresis modelling (Pranesh 2018) was applied to this problem to quantify the amount of CO2 retention in lignite core. Additionally, statistical model, multiple linear regression was applied to this problem to validate the experimental model, which showed good agreement.

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“…During the dewatering stage, the CSG production experienced more severe declines when the water flow rate was higher. This was concluded from the datum of 12 CSG wells by Zhao et al (2016). Wei et al (2013) found that both dewatering and initial production (two-phase flow in coal seams) stages witnessed more frequent production reductions.…”

Section: Coal Fines Induced Permeability Damagementioning

confidence: 94%

“…From the field trials from 12 CSG wells, Zhao et al (2016) observed that coal fines emerged during the water production stage ranged from 10 μm to 100 μm, and higher water flow rate led to more severe damage to CSG reservoirs. Wei et al (2013) further investigated the characteristics of coal fines production in a gas field in China.…”

Section: Introductionmentioning

confidence: 99%

Integrated geomechanical, geohydraulic and geological (3G) study of coal fines generation and migration

Bai¹

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This study, considering the Geomechanical, Geohydraulic and Geological (3G) aspects, delivers fundamental understandings of coal fines generation and migration during the CSG production processes, and useful guidelines are suggested to be implemented in the field to minimize production loss induced by coal fines behaviours. v Declaration by author This thesis is composed of my original work, and contains no material previously published or written by another person except where due reference has been made in the text. I have clearly stated the contribution by others to jointly-authored works that I have included in my thesis. I have clearly stated the contribution of others to my thesis as a whole, including statistical assistance, survey design, data analysis, significant technical procedures, professional editorial advice, financial support and any other original research work used or reported in my thesis. The content of my thesis is the result of work I have carried out since the commencement of my higher degree by research candidature and does not include a substantial part of work that has been submitted to qualify for the award of any other degree or diploma in any university or other tertiary institution. I have clearly stated which parts of my thesis, if any, have been submitted to qualify for another award. I acknowledge that an electronic copy of my thesis must be lodged with the University Library and, subject to the policy and procedures of The University of Queensland, the thesis be made available for research and study in accordance with the Copyright Act 1968 unless a period of embargo has been approved by the Dean of the Graduate School.

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Characteristics and generation mechanisms of coal fines in coalbed methane wells in the southern Qinshui Basin, China

Cited by 42 publications

References 28 publications

Numerical Simulation Study of Fines Migration Impacts on an Early Water Drainage Period in Undersaturated Coal Seam Gas Reservoirs

Numerical Simulation Study of Fines Migration Impacts on an Early Water Drainage Period in Undersaturated Coal Seam Gas Reservoirs

Permeability Damage and Supercritical Fluid Storage in the Cauvery Basin Neyveli Lignite Bed Containing Kaolinite Deposits during Alternative Injection of Brine and CO2

Integrated geomechanical, geohydraulic and geological (3G) study of coal fines generation and migration

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