A dynamic predictive permeability model in coal reservoirs: Effects of shrinkage behavior caused by water desorption

Miao, Yuqing; Li, Xiangfang; Yu, Zhou; Wu, Keliu; Chang, Yucui; Xiao, Zhihua; Wu, Nan; Lin, Weiren

doi:10.1016/j.petrol.2018.05.028

Cited by 27 publications

(6 citation statements)

References 67 publications

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“…Instead, Knudsen diffusion is likely to dominate, whereby diffusion is enhanced by the bouncing of gas molecules on the side of the pores. Nevertheless, many simulators assume only surface diffusion of adsorbed gas occurs within the matrix with all gas desorption taking place at the cleat face (King et al 1986;Ye et al 2014;Zang and Wang 2016;Miao et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Gas Diffusion in Coal Powders is a Multi-rate Process

2019

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Gas migration in coal is strongly controlled by surface diffusion of adsorbed gas within the coal matrix. Surface diffusion coefficients are obtained by inverse modelling of transient gas desorption data from powdered coals. The diffusion coefficient is frequently considered to be dependent on time and initial pressure. In this article, it is shown that the pressure dependence can be eliminated by performing a joint inversion of both the diffusion coefficient and adsorption isotherm. A study of the log-log slope of desorbed gas production rate against time reveals that diffusion within the individual coal particles is a multi-rate process. The application of a power-law probability density function of diffusion rates enables the determination of a single gas diffusion coefficient that is constant in both time and initial pressure.

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Section: Introductionmentioning

confidence: 99%

Gas Diffusion in Coal Powders is a Multi-rate Process

2019

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“…The Tarim Basin is the largest petroliferous onshore basin in China, with an area of 560,000 km 2 (Yang et al, 2007;Miao et al, 2018). The Lunnan uplift is located at the central east of the Tabei uplift in the Tarim Basin, and it belongs to a secondary-order subtectonic unit of the Tabei uplift.…”

Section: Location and Structural Evolution Of The Lunnan Upliftmentioning

confidence: 99%

Deformation Bands and Associated FIP Characteristics From High-Porous Triassic Reservoirs in the Tarim Basin, NW China: A Multiscale Analysis

Yan

Zhang

et al. 2021

Front. Earth Sci.

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Deformation bands are widely formed and distributed in Triassic high-porous rocks as a result of multistage tectonic movement. In this research, core observation, the rock thin section (fluorescence and casting thin section), FIB-SEM, X-ray diffraction, Raman laser, and thermometry of fluid inclusions were employed to describe the macro- and micro characteristics of deformation bands and their associated relationship with microfractures. Results indicate that the main types of deformation bands formed in the Lunnan Triassic high-porosity sandstone during the Yanshanian and Himalayan periods under different temperature and pressure conditions are compaction shear bands, and their quantity increases evidently with the distance of thrust faults. The density of deformation bands near the fault is about 15/m; porosity and permeability decrease sharply compared with those of the host rock. Microscopically, two obtained fluid-inclusion planes (FIPs) can be distinguished as 51 samples collected from 12 wells by the cutting relationship and mechanical characteristics. The homogenization temperature of associated aqueous inclusion is generally characterized by two peaks, mainly 70–80°C and 110–120°C, which were formed in the Late Yanshanian and Late Himalayan periods. The formation period of deformation bands induced by the intragranular microfractures improved the reservoir seepage capacity. In the later stage, as the interlayer and barrier with low porosity and low permeability affects the distribution of oil and gas, which is an important factor in this study of the local fluid dynamic field and high-quality reservoir evolution distribution.

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“…The development of CBM is the process of adsorption and desorption of gas and water. The adsorption and desorption of CBM and water can affect many properties of coal, such as porosity, permeability, mechanical properties and molecular structure of coal (Chen and Cheng 2015;Miao et al 2018;Ranathunga et al 2016;Tan et al 2018;Tang et al 2018;Xu et al 2014;Yi et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Combined control of fluid adsorption capacity and initial permeability on coal permeability

Wei

et al. 2022

Int J Coal Sci Technol

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The variations of strain and permeability of coal were systematically studied through the physical simulation of N2 and water injection. The effects of fluid adsorption capacity and initial permeability on strain, permeability and the dominant effect of pore pressure were discussed. The adsorption strain and strain rate of coal during water injection are significantly higher than those during N2 injection. An edge of free adsorption exists in the early phase of N2 and water injection, which is related to fluid saturation. Within this boundary, the strain rate and pore pressure are independent. Moreover, the injection time of initial stage accounts for about 20% of the total injection time, but the strain accounts for 70% of the total strain. For water injection, this boundary is about half of water saturation of coal. Besides, the influence of pore pressure on permeability is complex, which is controlled by adsorption capacity and initial permeability of coal. When the initial permeability is large enough, the effect of adsorption strain on permeability is relatively weak, and the promoting effect of pore pressure on fluid migration is dominant. Therefore, the permeability increases with increasing pore pressure. When the initial permeability is relatively low, the pore pressure may have a dominant role in promoting fluid migration for the fluid with weak adsorption capacity. However, for the fluid with strong adsorption capacity, the adsorption strain caused by pore pressure may play a leading role, and the permeability reduces first and then ascends with increasing pore pressure.

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A dynamic predictive permeability model in coal reservoirs: Effects of shrinkage behavior caused by water desorption

Cited by 27 publications

References 67 publications

Gas Diffusion in Coal Powders is a Multi-rate Process

Gas Diffusion in Coal Powders is a Multi-rate Process

Deformation Bands and Associated FIP Characteristics From High-Porous Triassic Reservoirs in the Tarim Basin, NW China: A Multiscale Analysis

Combined control of fluid adsorption capacity and initial permeability on coal permeability

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