Effect of saline sedimentary environment on pore throats of shale

Zhao, Zhongxiang; Wu, Songbai; He, Mengqing; Yang, Fan

doi:10.3389/feart.2022.974441

Cited by 3 publications

(3 citation statements)

References 18 publications

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“…The pore throat is the narrowest channel connecting different pores within the coal, and the size of the pore throat affects the permeability and connectivity within the coal. The larger the pore throat, the easier it is for fluids such as gas and moisture to flow inside the coal. , Pore throats are critical for the migration of pore water in the pore space during LN 2 freezing or freeze–thawing. The pore water phase transition also leads to the creation of different types of pore throats and changes in the number of different sized pore throats.…”

Section: Resultsmentioning

confidence: 99%

“…The larger the pore throat, the easier it is for fluids such as gas and moisture to flow inside the coal. 33,34 Pore throats are critical for the migration of pore water in the pore space during LN 2 freezing or freeze−thawing. The pore water phase transition also leads to the creation of different types of pore throats and changes in the number of different sized pore throats.…”

Section: Variation Of Water Content Volume Fraction In Different Coal...mentioning

confidence: 99%

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Pore Water Microscale Response of Different Water-Saturated Coal Samples under a Freeze–Thaw Degradation Effect

Qin,

Liu,

et al. 2024

Energy Fuels

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Pore water content directly affects the effect of liquid nitrogen (LN 2 ) penetration, and the study of the freeze− thaw response of the pore water of different saturated coal samples in the process of LN 2 penetration is crucial for promoting the development of LN 2 fracturing technology. In this work, a LN 2 freeze−thaw study was carried out with three types of coal samples, namely, dry, naturally water-saturated, and fully water-saturated samples, and the pore water microscale response of the coal samples under freeze−thaw degradation was analyzed by a lowfield NMR technique. The results show that (1) the swelling effect caused by the pore free water phase transition is the key to the lowtemperature penetration enhancement of coal. (2) As the coal samples were subjected to different times of LN 2 , the pore water fugacity was affected by the pore evolution; in 0−50 min, the pore water content of the BBT coal sample was positively correlated with the freezing time, while the opposite was true for the BT coal sample; in 50−150 min, both samples showed a tendency to increase first and then decrease. The pore water content before and after freeze−thaw increased by 26.90% in a GT coal sample, 237.20% in a BBT coal sample, and 118.86% in a BT coal sample. (3) The pore water of GT coal sample is mainly in the closed pores, which is reduced during freeze−thaw. The pore water of BBT and BT coal samples are mainly distributed in open pores, the effective pore water of BBT coal sample is the highest at the end of freezing and thawing, the effective pore water of BT coal sample is the most at the beginning of freezing and thawing, and the maximum effective pore water content of the two samples is close to each other. Compared with BT coal sample, BBT coal sample have a better fracturing effect and better pore water storage. (4) As the specimen is degraded by freezing and thawing, internal pore channels are developed, the frozen specimen forms a combination with coal as the main body and that with ice and water as the auxiliary body, the heat conduction of the specimen is weakened, and the conduction efficiency is reduced. By increasing the duration of LN 2 freezing, the influence of pore water on coal fracturing can be enhanced and the efficiency of LN 2 action can be improved.

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Section: Resultsmentioning

confidence: 99%

Section: Variation Of Water Content Volume Fraction In Different Coal...mentioning

confidence: 99%

Pore Water Microscale Response of Different Water-Saturated Coal Samples under a Freeze–Thaw Degradation Effect

Qin,

Liu,

et al. 2024

Energy Fuels

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“…Stress sensitivity is the property of reservoir rock permeability to change with the variation of stress state [9,10]. Stress sensitivity of reservoirs (especially low-permeability reservoirs) is one of the research hotspots in petroleum engineering in recent years [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Study of the Seepage Mechanism in Thick Heterogeneous Gas Reservoirs

Huang¹,

Jiang²,

Huang³

et al. 2023

Fluid Dynamics &Amp; Materials Processing

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The seepage mechanism plays a crucial role in low-permeability gas reservoirs. Compared with conventional gas reservoirs, low-permeability sandstone gas reservoirs are characterized by low porosity, low permeability, strong heterogeneity, and high water saturation. Moreover, their percolation mechanisms are more complex. The present work describes a series of experiments conducted considering low-permeability sandstone cores under pressuredepletion conditions (from the Xihu Depression in the East China Sea Basin). It is shown that the threshold pressure gradient of a low-permeability gas reservoir in thick layers is positively correlated with water saturation and negatively correlated with permeability and porosity. The reservoir stress sensitivity is related to permeability and rock composition. Stress sensitivity is generally low when permeability is high or in the early stage of gas reservoir development. It is also shown that in sand conglomerates, especially the more sparsely filled parts, the interstitial materials among the conglomerates can be rapidly dislodged from the skeleton particles under stress. This material can therefore disperse, migrate, and block the pore throat producing serious, stress-sensitive damage.

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Elemental Geochemical Distribution of the Jurassic Yan'an Formation in the Ningdong Coalfield and its Controlling Effect on Coal Reservoir Properties

Zhang

et al. 2023

Nat Resour Res

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Effect of saline sedimentary environment on pore throats of shale

Cited by 3 publications

References 18 publications

Pore Water Microscale Response of Different Water-Saturated Coal Samples under a Freeze–Thaw Degradation Effect

Pore Water Microscale Response of Different Water-Saturated Coal Samples under a Freeze–Thaw Degradation Effect

Study of the Seepage Mechanism in Thick Heterogeneous Gas Reservoirs

Elemental Geochemical Distribution of the Jurassic Yan'an Formation in the Ningdong Coalfield and its Controlling Effect on Coal Reservoir Properties

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