A multi-scale quadruple-continuum model for production evaluation of shale gas reservoirs considering complex gas transfer mechanisms and geomechanics

Micheal, Marembo; Xu, Wen; Jin, Juan; Yu, Hao; Liu, Jian Dong; Jiang, Wei Dong; Liu, He; Wu, HengAn

doi:10.1016/j.petrol.2022.110419

Cited by 17 publications

(35 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Note that shale pore structures are complex, and the pore size ranges from the nanoscale to macroscale. − Therefore, it is essential to explore the hydrogen diffusion from the multiscale perspective. − In this work, we primarily concentrated on the fundamental diffusivity of hydrogen in clay nanopores, because it is the foundation for assessing the hydrogen leakage risk through caprocks and geological storage safety. Our results can be incorporated into upscaling frameworks such as the Lattice Boltzmann and pore network model to estimate the hydrogen transport through multiscale caprocks and provide a more accurate estimate of the leakage rate.…”

Section: Resultsmentioning

confidence: 99%

Hydrogen Diffusion in Clay Slit: Implications for the Geological Storage

et al. 2022

View full text Add to dashboard Cite

We determined the self-diffusion coefficients of hydrogen in clay (montmorillonite) nanopores using molecular dynamics under subsurface conditions. We explored the effects of temperature, pressure, pore size, moisture content, and salinity. Our results show that the self-diffusion coefficient of hydrogen is on the order of magnitude of 10–8 m2/s. The diffusivity of confined hydrogen increases moderately with temperature and slit aperture but declines with pressure. The estimated density profile suggests that only one dense layer of hydrogen molecules is adsorbed near the slit surface. The distinct diffusion coefficients in the parallel and perpendicular directions to the basal surfaces confirm the confinement effect of the substrates. As the volume ratio of hydrogen increases, the existing pattern of hydrogen changes from a droplet to a layer sandwiched by the aqueous solution. The water bridge will act as a piston for the hydrogen droplet and impede hydrogen diffusion. However, when the hydrogen and brine form a stratified structure, the self-diffusion coefficient of hydrogen sandwiched by two brine films is similar to that of confined pure gas at the same pressure and temperature conditions. If the brine salinity reaches some extent, part of brine and hydrogen molecules will mix as a new phase, which slightly inhibits the hydrogen diffusion. This work provides a better insight into hydrogen diffusion through the clay nanopores, which is critical for reliably assessing the risk of hydrogen leakage through caprocks.

show abstract

Section: Resultsmentioning

confidence: 99%

Hydrogen Diffusion in Clay Slit: Implications for the Geological Storage

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Quadruple-continuum modeling approach for quantifying gas exchange across domains . (a) Multistage hydraulically fractured horizontal well with natural fractures at the macroscale.…”

Section: Storage and Transport Mechanism Of Gas In Shale Reservoirsmentioning

confidence: 99%

“…The Knudsen number of gas in the kerogen pores ranges between 0.01 and 1. Therefore, the common flow mechanisms in the kerogen are Knudsen diffusion, viscous flow, and surface diffusion. ,, The pore diameters of the nanoscale determine the rate of collisions between the molecules and the walls of the pores, thus affecting the migration of gas and the flow mechanisms. ,, Yu et al used MD simulation to investigate the behavior of methane molecules at the atomic scale and observed that the trajectories of the representative flowing methane particles at varying pressures were different. For example, when pressure is 50 MPa, the methane particles near the solid walls are almost immobile because of the dense adsorption layers, and the migration of the gas molecules occurs as pressure decreases.…”

Section: Storage and Transport Mechanism Of Gas In Shale Reservoirsmentioning

confidence: 99%

“…Zhang et al implemented the transfer from the kerogen to the inorganic matrix by using the Warren–Root shape factor because the kerogen is completely embedded in the inorganic matrix, and it is easy for the pressure to reach a steady state. Because of changes in pressure in the subsurface, the adsorbed gas is converted into free gas, which then migrates to the inorganic matrix, and the transfer function of the Warren–Root model is used to capture this exchange . From Figure b, a snippet of the exchange between the kerogen and inorganic matrix from the work of Micheal et al is shown, where the transfer of gas from the kerogen to the inorganic matrix is represented by T kema .…”

Section: Storage and Transport Mechanism Of Gas In Shale Reservoirsmentioning

confidence: 99%

See 1 more Smart Citation

Hydraulic Fracturing and Enhanced Recovery in Shale Reservoirs: Theoretical Analysis to Engineering Applications

et al. 2023

Energy Fuels

Self Cite

View full text Add to dashboard Cite

Shale reservoirs are extensively exploited using hydraulic fracturing, which forms multiple cracks that connect with the existing natural fractures to create a continuous path for the gas stored in the kerogen to flow to the production well. Apart from the tedious nature of hydraulic fracturing, the mechanism of the storage and flow of gas is equally complex since multiple phases and scales are involved. An accurate understanding of hydraulic fracturing coupled with a strategy of analyzing the flow and overall recovery of gas is paramount to ensure efficient exploitation. In this work, a comprehensive review of the recent strategies used in analyzing the hydraulic fracturing, storage, flow, and recovery of gas is presented. To begin with, the experimental, analytical, and numerical approaches pertinent to hydraulic fracturing are deeply explored. Additionally, the flow of gas through the newly opened channels is accounted for by using a quadruple-domain approach where the mechanisms of flow in shale reservoirs at the nanoscale, microscale, mesoscale, and macroscale are considered. Furthermore, a strategy to capture the multiple phases, including gas, oil, and water, and recover both carbon dioxide and methane is explored through thermal and enhanced gas recovery approaches. This review provides a baseline for understanding how the hydraulic fracture evolves and propagates to create new channels that contribute to the flow of gas, how the gas flows through the created channels across the many scales of the shale reservoir, and how to improve recovery from shale reservoirs.

show abstract

“…Industrial oil and gas flow can hardly be obtained from shale reservoir with extremely low porosity and permeability in natural state. − Horizontal drilling and multistage fracturing technology have realized large-scale commercial exploitation of shale oil and gas, which is changing the world energy pattern. − As shown in the Figure , the shale reservoir after fracturing becomes a multiscale complex fracture network structure composed of a matrix, natural microfractures, and hydraulic fractures; the gas flow characteristics in the pore and fracture structures of different scales are quite different. − The Knudsen number K n can be used to divide the gas flow regime based on the pore and fracture size. When K n > 0.2, the flow regime is dominated by the diffusion effect; when K n < 0.01, the flow is dominated by seepage; and when 0.001 < K n < 0.2, the gas flow is in the form of coexistence of multiple flow patterns mainly including slip flow, surface diffusion, Fick diffusion, and Knudsen diffusion. − Shale gas is stored in various states in a shale reservoir, mainly including free gas, adsorbed gas, and dissolved gas; the gas mass transfer is the common result of the above multiple flow regimes. In addition, the fluid–solid coupling effect of shale reservoir is obvious during the exploitation process due to the large burial depth. − It is urgent to establish a productivity model of shale gas horizontal wells that can comprehensively considers the combined effects of multiple flow mechanisms and fluid–solid coupling effects of a shale reservoir, so as to achieve accurate productivity prediction and evaluation and optimize the location and spacing of fracturing wells.…”

Section: Introductionmentioning

confidence: 99%

Study on Multiscale Fluid–Solid Coupling Theoretical Model and Productivity Analysis of Horizontal Well in Shale Gas Reservoirs

et al. 2023

View full text Add to dashboard Cite

In order to study the productivity dynamic evolution laws of shale gas horizontal well, a multiscale seepage theoretical model considering the fluid–solid coupling effect is proposed first in this paper, which introduces an anisotropic matrix permeability model that comprehensively considers multiple flow regimes and an artificial hydraulic fracture conductivity model that considers proppant deformation and embedment. Then the reliability of the theoretical model is verified by the field production data obtained from the Marcellus shale. Based on the established productivity model, the evolution laws of pore pressure and permeability in different areas of the reservoir with different production periods are studied first, and then the shale gas production rate and cumulative production under different physical mechanisms, different shale gas flow regimes, and different reservoir parameters are quantified and analyzed. The simulation results show that the pore pressure in the hydraulic fracture area decreases rapidly at the initial stage of production, resulting in large deformation, and the fracture conductivity tends to be stable gradually at the later stage of production. The desorption effect will increase shale gas production, while the stress sensitivity is just the opposite. When only real gas flow is considered, the gas cumulative production is the highest. The fluid–solid coupling of hydraulic fractures has a great impact on the production, while the fluid–solid coupling in the matrix area has a small impact on the production, which can be ignored if appropriate. During the sensitivity analysis of reservoir parameters, it is observed that the influence of parameters of hydraulic fractures on production is much higher than that of matrix regional parameters. During the production process, these influencing factors can be adjusted according to the change of production data to achieve the optimization of shale gas production. In a word, the new model proposed in this paper provides a more accurate method to estimate the impact of multiple physical mechanisms, especially the fluid–solid coupling effect, on shale gas production compared with the existing model. The research results of this study can provide some reference and guidance for the dynamic prediction of shale gas production and optimization of production parameters.

show abstract

A multi-scale quadruple-continuum model for production evaluation of shale gas reservoirs considering complex gas transfer mechanisms and geomechanics

Cited by 17 publications

References 74 publications

Hydrogen Diffusion in Clay Slit: Implications for the Geological Storage

Hydrogen Diffusion in Clay Slit: Implications for the Geological Storage

Hydraulic Fracturing and Enhanced Recovery in Shale Reservoirs: Theoretical Analysis to Engineering Applications

Study on Multiscale Fluid–Solid Coupling Theoretical Model and Productivity Analysis of Horizontal Well in Shale Gas Reservoirs

Contact Info

Product

Resources

About