Estimating diffusion coefficients of shale oil, gas, and condensate with nano-confinement effect

Du, Fengshuang; Nojabaei, Bahareh

doi:10.1016/j.petrol.2020.107362

Cited by 26 publications

(11 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Different values of tortuosity, ranging between 1.74 and 2.69, were obtained, which are reasonable values for shale tortuosity given past results in the literature. 49…”

Section: Resultsmentioning

confidence: 99%

Predicting Surface Diffusivities of Gas Molecules in Shale

Rigby

2020

Energy Fuels

View full text Add to dashboard Cite

Carbon dioxide injection can be utilized as a means of both enhancing gas recovery from shales and sequestering carbon and thereby simultaneously addressing the growing worldwide gas demand, as well as the challenge of greenhouse gas emissions. Greater mobility of CO 2 within the shale improves the displacement efficiency of the originally present CH 4 , as well as increasing the CO 2 penetration of the shale formation. Previous investigations have indicated that surface diffusion is much more significant than the bulk gas transport in shale gas reservoirs because of the larger fraction of the adsorbed phase found in the nanopores of shales. The surface diffusivities of CO 2 on different shales, at various temperatures, have been measured. A fractal theory for predicting the Arrhenius parameters of the surface diffusivity of molecules on heterogeneous surfaces has been applied to the surface diffusion of CO 2 in shales. In line with the theory, it was found that both the pre-exponential factor and the activation energy are functions of the surface fractal dimension. Hence, the surface diffusivity, around a monolayer coverage, on shales could be established from an equilibrium gas adsorption isotherm, once the Arrhenius parameters have been calibrated for the specific chemical species. To the best of our knowledge, this study is the first to apply the fractal theory and effectively predict, a priori, surface diffusivity parameters for such structurally and chemically heterogeneous natural samples as shales. This theory now enables the optimization of the designs of CO 2 injection in field applications since surface diffusion is of major importance in the apparent permeability and, thus, in the gas flow mechanisms.

show abstract

“…Different values of tortuosity, ranging between 1.74 and 2.69, were obtained, which are reasonable values for shale tortuosity given past results in the literature. 49…”

Section: Resultsmentioning

confidence: 99%

Predicting Surface Diffusivities of Gas Molecules in Shale

Rigby

2020

Energy Fuels

View full text Add to dashboard Cite

show abstract

“…It is significant to construct a microscopic visible model to reflect the actual porous media. [91][92][93][94][95][96][97][98][99] Figure 13 shows the CO 2 flooding process based on a visible porous medium model. Brine (colorless) sealed by oil (dark) can be observed at the end of channels after oil injection (Figure 13a).…”

Section: Pore-scale Visualizationmentioning

confidence: 99%

Review on Pore Structure Characterization and Microscopic Flow Mechanism of CO₂ Flooding in Porous Media

Tang

Hou

et al. 2020

Energy Tech

View full text Add to dashboard Cite

Rapidly rising emissions of greenhouse gases into the atmosphere lead to the greenhouse effect and accelerate the exacerbation of the global climate. [1] Greenhouse gases include carbon dioxide (CO 2), ozone (O 3), nitric oxide (N 2 O), methane (CH 4), hydrogen fluoride, the chlorine carbide class (CFCs, HFCs, HCFCs), and perfluorinated carbide (PFCs) and sulfur hexafluoride (SF 6). The concentration of CO 2 is the highest in the atmosphere among greenhouse gases, and it significantly dominates global warming. [2] The process of the greenhouse effect and the impact of greenhouse gases on global warming are shown in Figure 1. Carbon is one of the most important elements of earth's structure and living things. It widely exists in the biosphere, lithosphere, hydrosphere, and atmosphere and circulates continuously with the movement of the Earth. CO 2 plays an important role in the cycle. Green plants absorb CO 2 from the atmosphere, and CO 2 is converted into organic matter and oxygen is also released through photosynthesis with the participation of water, as shown in Figure 2. [3,4] Before the industrial revolution, the carbon cycle has been kept in balance for millions of years. After the industrial revolution, human beings began to utilize fossil fuels to obtain energy. The balance of nature is thus destroyed, leading to climate anomalies (e.g., global warming) due to the increased concentration of CO 2 caused by the burning of fossil fuels and other industrial activities. Therefore, reducing emissions of CO 2 and other greenhouse gases is essential for protecting the natural environment. [5,6] At present, carbon emissions can be reduced by decreasing energy consumption, improving energy utilization efficiency, replacing fossil fuels with clean energy (e.g., solar energy, wind energy, geothermal energy, and hydrogen energy), and carbon capture and storage (CCS). However, it is still hard for most of the clean energy to completely replace fossil fuels in the near future because of safety, technology availability, and economical efficiency. [7] CCS is an important technological means to reduce carbon emission. [8,9] However, CCS requires high costs and may cause leakage of carbon because the captured carbon is usually sequestrated in saline aquifers, coal seams, depleted reservoirs, etc. [10-12] Therefore, carbon capture, utilization and storage (CCUS) has been acknowledged as a promising technology to achieve efficient reduction of carbon and also generate economic benefits, which is more practical and economical. [13] CO 2 is an important material for industry and has been applied in many fields, as shown in Figure 3. [14,15] In the food industry, CO 2 is used in the production of carbonized beverages, food preservation, and industrial processing as a refrigerant and protective gas. It can also be applied to synthesize chemicals, drugs, polymers, such as degradable plastics, etc. High-purity

show abstract

“…CO 2 huff-n-puff showed a better performance than gas flooding, and more than 50% of the injected CO 2 was successfully sequestrated in the reservoir. Du and Nojabaei (2020; included the nano-confinement effect to calculate the diffusion coefficient of CO 2 in a shale gas reservoir and optimized the huff-n-puff gas injection parameters.…”

Section: Introductionmentioning

confidence: 99%

Re-Fracturing vs. CO2 Huff-n-Puff Injection in a Tight Shale Reservoir for Enhancing Gas Production

Wang

et al. 2023

Front. Energy Res.

View full text Add to dashboard Cite

Field production data indicate that the shale gas production rate decreases sharply after a few years of the first fracking. Feasible enhanced gas recovery (EGR) approaches are very necessary to be investigated. In this study, we compared re-fracturing with a huff-n-puff gas injection scheme in a shale gas reservoir for EGR. A fully compositional simulation approach coupled with a dual porosity and dual permeability model is used. The gas production performances by using different fracturing fluids (i.e., slickwater and supercritical CO2) are evaluated. The effects of huff-n-puff parameters and matrix permeability on the gas production rate and carbon sequestration are investigated. The results show that using a re-fracturing approach yields a better recovery performance than the huff-n-puff gas injection method. Re-fracturing using supercritical CO2 performs better than using slickwater because the former can create complex three-dimensional fracture networks. Huff-n-puff CO2 injection can enhance the gas recovery effectively in ultra-tight formations. In a relatively high permeable formation, viscous flow instead of adsorption-desorption isotherms becomes the primary mass transfer mechanisms, resulting in a lower gas recovery. Both the re-fracturing treatment and huff-n-puff CO2 injection are profitable from a long-term cash flowback perspective.

show abstract

Estimating diffusion coefficients of shale oil, gas, and condensate with nano-confinement effect

Cited by 26 publications

References 47 publications

Predicting Surface Diffusivities of Gas Molecules in Shale

Predicting Surface Diffusivities of Gas Molecules in Shale

Review on Pore Structure Characterization and Microscopic Flow Mechanism of CO₂ Flooding in Porous Media

Re-Fracturing vs. CO2 Huff-n-Puff Injection in a Tight Shale Reservoir for Enhancing Gas Production

Contact Info

Product

Resources

About

Estimating diffusion coefficients of shale oil, gas, and condensate with nano-confinement effect

Cited by 26 publications

References 47 publications

Predicting Surface Diffusivities of Gas Molecules in Shale

Predicting Surface Diffusivities of Gas Molecules in Shale

Review on Pore Structure Characterization and Microscopic Flow Mechanism of CO2 Flooding in Porous Media

Re-Fracturing vs. CO2 Huff-n-Puff Injection in a Tight Shale Reservoir for Enhancing Gas Production

Contact Info

Product

Resources

About

Review on Pore Structure Characterization and Microscopic Flow Mechanism of CO₂ Flooding in Porous Media